1 Shape Healing {#occt_user_guides__shape_healing}
6 @section occt_shg_1 Overview
8 @subsection occt_shg_1_1 Introduction
10 This manual explains how to use Shape Healing. It provides basic documentation on its operation. For advanced information on Shape Healing and its applications, see our <a href="https://www.opencascade.com/content/tutorial-learning">E-learning & Training</a> offerings.
12 The **Shape Healing** toolkit provides a set of tools to work on the geometry and topology of Open CASCADE Technology (**OCCT**) shapes. Shape Healing adapts shapes so as to make them as appropriate for use by Open CASCADE Technology as possible.
14 @subsection occt_shg_1_2 Examples of use
16 Here are a few examples of typical problems with illustrations of how Shape Healing deals with them:
18 #### Face with missing seam edge
20 The problem: Face on a periodical surface is limited by wires which make a full trip around the surface. These wires are closed in 3d but not closed in parametric space of the surface. This is not valid in Open CASCADE.
21 The solution: Shape Healing fixes this face by inserting seam edge which combines two open wires and thus closes the parametric space. Note that internal wires are processed correctly.
23 #### Wrong orientation of wires
24 The problem: Wires on face have incorrect orientation, so that interior and outer parts of the face are mixed.
25 The solution: Shape Healing recovers correct orientation of wires.
27 #### Self-intersecting wire
28 The problem: Face is invalid because its boundary wire has self-intersection (on two adjacent edges)
29 The solution: Shape Healing cuts intersecting edges at intersection points thus making boundary valid.
32 The problem: There is a gap between two edges in the wire, so that wire is not closed
33 The solution: Shape Healing closes a gap by inserting lacking edge.
35 @subsection occt_shg_1_3 Toolkit Structure
37 **Shape Healing** currently includes several packages that are designed to help you to:
38 * analyze shape characteristics and, in particular, identify shapes that do not comply with Open CASCADE Technology validity rules
39 * fix some of the problems shapes may have
40 * upgrade shape characteristics for users needs, for example a C0 supporting surface can be upgraded so that it becomes C1 continuous.
42 The following diagram shows dependencies of API packages:
44 @figure{/user_guides/shape_healing/images/shape_healing_image009.svg,"Shape Healing packages",420}
46 Each sub-domain has its own scope of functionality:
47 * analysis -- exploring shape properties, computing shape features, detecting violation of OCCT requirements (shape itself is not modified);
48 * fixing -- fixing shape to meet the OCCT requirements (the shape may change its original form: modifying, removing, constructing sub-shapes, etc.);
49 * upgrade -- shape improvement for better usability in Open CASCADE Technology or other algorithms (the shape is replaced with a new one, but geometrically they are the same);
50 * customization -- modifying shape representation to fit specific needs (shape is not modified, only the form of its representation is modified);
51 * processing -- mechanism of managing shape modification via a user-editable resource file.
53 Message management is used for creating messages, filling them with various parameters and storing them in the trace file. This tool provides functionality for attaching messages to the shapes for deferred analysis of various run-time events. In this document only general principles of using Shape Healing will be described. For more detailed information, see the corresponding header files.
55 Tools responsible for analysis, fixing and upgrading of shapes can give the information about how these operations were performed. This information can be obtained by the user with the help of mechanism of status querying.
57 @subsection occt_shg_1_4 Querying the statuses
59 Each fixing and upgrading tool has its own status, which is reset when their methods are called. The status can contain several flags, which give the information about how the method was performed. For exploring the statuses, a set of methods named *Status...()* is provided. These methods accept enumeration *ShapeExtend_Status* and return True if the status has the corresponding flag set. The meaning of flags for each method is described below.
61 The status may contain a set of Boolean flags (internally represented by bits). Flags are coded by enumeration ShapeExtend_Status. This enumeration provides the following families of statuses:
62 * *ShapeExtend_OK* -- The situation is OK, no operation is necessary and has not been performed.
63 * *ShapeExtend_DONE* -- The operation has been successfully performed.
64 * *ShapeExtend_FAIL* -- An error has occurred during operation.
66 It is possible to test the status for the presence of some flag(s), using Status...() method(s) provided by the class:
69 if ( object.Status.. ( ShapeExtend_DONE ) ) {// something was done
73 8 'DONE' and 8 'FAIL' flags, named ShapeExtend_DONE1 ... ShapeExtend_FAIL8, are defined for a detailed analysis of the encountered situation. Each method assigns its own meaning to each flag, documented in the header for that method. There are also three enumerative values used for testing several flags at a time:
74 * *ShapeExtend_OK* -- if no flags have been set;
75 * *ShapeExtend_DONE* -- if at least one ShapeExtend_DONEi has been set;
76 * *ShapeExtend_FAIL* -- if at least one ShapeExtend_FAILi has been set.
78 @section occt_shg_2 Repair
80 Algorithms for fixing problematic (violating the OCCT requirements) shapes are placed in package *ShapeFix*.
82 Each class of package *ShapeFix* deals with one certain type of shapes or with some family of problems.
84 There is no necessity for you to detect problems before using *ShapeFix* because all components of package *ShapeFix* make an analysis of existing problems before fixing them by a corresponding tool from package of *ShapeAnalysis* and then fix the discovered problems.
86 The *ShapeFix* package currently includes functions that:
87 * add a 2D curve or a 3D curve where one is missing,
88 * correct a deviation of a 2D curve from a 3D curve when it exceeds a given tolerance value,
89 * limit the tolerance value of shapes within a given range,
90 * set a given tolerance value for shapes,
91 * repair the connections between adjacent edges of a wire,
92 * correct self-intersecting wires,
94 * correct gaps between 3D and 2D curves,
95 * merge and remove small edges,
96 * correct orientation of shells and solids.
98 @subsection occt_shg_2_1 Basic Shape Repair
100 The simplest way for fixing shapes is to use classes *ShapeFix_Shape* and *ShapeFix_Wireframe* on a whole shape with default parameters. A combination of these tools can fix most of the problems that shapes may have.
101 The sequence of actions is as follows :
103 1. Create tool *ShapeFix_Shape* and initialize it by shape:
105 Handle(ShapeFix_Shape) sfs = new ShapeFix_Shape;
108 2. Set the basic precision, the maximum allowed tolerance, the minimal allowed tolerance:
110 sfs->SetPrecision ( Prec );
111 sfs->SetMaxTolerance ( maxTol );
112 sfs->SetMinTolerance ( mintol );
115 * *Prec* -- basic precision.
116 * *maxTol* -- maximum allowed tolerance. All problems will be detected for cases when a dimension of invalidity is larger than the basic precision or a tolerance of sub-shape on that problem is detected.
117 The maximum tolerance value limits the increasing tolerance for fixing a problem such as fix of not connected and self-intersected wires. If a value larger than the maximum allowed tolerance is necessary for correcting a detected problem the problem can not be fixed.
118 The maximal tolerance is not taking into account during computation of tolerance of edges in *ShapeFix_SameParameter()* method and *ShapeFix_Edge::FixVertexTolerance()* method.
119 See @ref occt_shg_2_3_8 for details.
120 * *minTol* -- minimal allowed tolerance. It defines the minimal allowed length of edges. Detected edges having length less than the specified minimal tolerance will be removed if *ModifyTopologyMode* in Repairing tool for wires is set to true.
121 See @ref occt_shg_2_3_7 for details.
129 TopoDS_Shape aResult = sfs->Shape();
131 In some cases using only *ShapeFix_Shape* can be insufficient. It is possible to use tools for merging and removing small edges and fixing gaps between 2D and 3D curves.
133 5. Create *ShapeFix_Wireframe* tool and initialize it by shape:
135 Handle(ShapeFix_Wirefarme) SFWF = new ShapeFix_Wirefarme(shape);
137 Handle(ShapeFix_Wirefarme) SFWF = new ShapeFix_Wirefarme;
140 6. Set the basic precision and the maximum allowed tolerance:
142 sfs->SetPrecision ( Prec );
143 sfs->SetMaxTolerance ( maxTol );
145 See the description for *Prec* and *maxTol* above.
146 7. Merge and remove small edges:
148 SFWF->DropSmallEdgesMode() = Standard_True;
149 SFWF->FixSmallEdges();
151 **Note:** Small edges are not removed with the default mode, but in many cases removing small edges is very useful for fixing a shape.
152 8. Fix gaps for 2D and 3D curves
158 TopoDS_Shape Result = SFWF->Shape();
162 @subsection occt_shg_2_2 Shape Correction.
164 If you do not want to make fixes on the whole shape or make a definite set of fixes you can set flags for separate fix cases (marking them ON or OFF) and you can also use classes for fixing specific types of sub-shapes such as solids, shells, faces, wires, etc.
166 For each type of sub-shapes there are specific types of fixing tools such as *ShapeFix_Solid, ShapeFix_Shell, ShapeFix_Face, ShapeFix_Wire,* etc.
168 @subsubsection occt_shg_2_2_1 Fixing sub-shapes
169 If you want to make a fix on one sub-shape of a certain shape it is possible to take the following steps:
170 * create a tool for a specified sub-shape type and initialize this tool by the sub-shape;
171 * create a tool for rebuilding the shape and initialize it by the whole shape (section 5.1);
172 * set a tool for rebuilding the shape in the tool for fixing the sub-shape;
174 * get the resulting whole shape containing a new corrected sub-shape.
176 For example, in the following way it is possible to fix face *Face1* of shape *Shape1*:
179 //create tools for fixing a face
180 Handle(ShapeFix_Face) SFF= new ShapeFix_Face;
182 // create tool for rebuilding a shape and initialize it by shape
183 Handle(ShapeBuild_ReShape) Context = new ShapeBuild_ReShape;
184 Context->Apply(Shape1);
186 //set a tool for rebuilding a shape in the tool for fixing
187 SFF->SetContext(Context);
189 //initialize the fixing tool by one face
196 TopoDS_Shape NewShape = Context->Apply(Shape1);
197 //Resulting shape contains the fixed face.
200 A set of required fixes and invalid sub-shapes can be obtained with the help of tools responsible for the analysis of shape validity (section 3.2).
202 @subsection occt_shg_2_3 Repairing tools
204 Each class of package ShapeFix deals with one certain type of shapes or with a family of problems. Each repairing tool makes fixes for the specified shape and its sub-shapes with the help of method *Perform()* containing an optimal set of fixes. The execution of these fixes in the method Perform can be managed with help of a set of control flags (fixes can be either forced or forbidden).
206 @subsubsection occt_shg_2_3_1 General Workflow
208 The following sequence of actions should be applied to perform fixes:
210 2. Set the following values:
211 + the working precision by method *SetPrecision()* (default 1.e-7)
212 + set the maximum allowed tolerance by method *SetMaxTolerance()* (by default it is equal to the working precision).
213 + set the minimum tolerance by method *SetMinTolerance()* (by default it is equal to the working precision).
214 + set a tool for rebuilding shapes after the modification (tool *ShapeBuild_ReShape*) by method *SetContext()*. For separate faces, wires and edges this tool is set optionally.
215 + to force or forbid some of fixes, set the corresponding flag to 0 or 1.
216 3. Initialize the tool by the shape with the help of methods Init or Load
217 4. Use method *Perform()* or create a custom set of fixes.
218 5. Check the statuses of fixes by the general method *Status* or specialized methods *Status_*(for example *StatusSelfIntersection* (*ShapeExtentd_DONE*)). See the description of statuses below.
219 6. Get the result in two ways :
220 - with help of a special method *Shape(),Face(),Wire().Edge()*.
221 - from the rebuilding tool by method *Apply* (for access to rebuilding tool use method *Context()*):
223 TopoDS_Shape resultShape = fixtool->Context()->Apply(initialShape);
225 Modification fistory for the shape and its sub-shapes can be obtained from the tool for shape re-building (*ShapeBuild_ReShape*).
228 TopoDS_Shape modifsubshape = fixtool->Context() -> Apply(initsubshape);
232 @subsubsection occt_shg_2_3_2 Flags Management
234 The flags *Fix...Mode()* are used to control the execution of fixing procedures from the API fixing methods. By default, these flags have values equal to -1, this means that the corresponding procedure will either be called or not called, depending on the situation. If the flag is set to 1, the procedure is executed anyway; if the flag is 0, the procedure is not executed. The name of the flag corresponds to the fixing procedure that is controlled. For each fixing tool there exists its own set of flags. To set a flag to the desired value, get a tool containing this flag and set the flag to the required value.
236 For example, it is possible to forbid performing fixes to remove small edges - *FixSmall*
239 Handle(ShapeFix_Shape) Sfs = new ShapeFix_Shape(shape);
240 Sfs-> FixWireTool ()->FixSmallMode () =0;
242 TopoDS_Shape resShape = Sfs->Shape();
246 @subsubsection occt_shg_2_3_3 Repairing tool for shapes
248 Class *ShapeFix_Shape* allows using repairing tools for all sub-shapes of a shape. It provides access to all repairing tools for fixing sub-shapes of the specified shape and to all control flags from these tools.
250 For example, it is possible to force the removal of invalid 2D curves from a face.
253 TopoDS_Face face … // face with invalid 2D curves.
254 //creation of tool and its initialization by shape.
255 Handle(ShapeFix_Shape) sfs = new ShapeFix_Shape(face);
256 //set work precision and max allowed tolerance.
257 sfs->SetPrecision(prec);
258 sfs->SetMaxTolerance(maxTol);
259 //set the value of flag for forcing the removal of 2D curves
260 sfs->FixWireTool()->FixRemovePCurveMode() =1;
264 if(sfs->Status(ShapeExtend_DONE) ) {
265 cout << "Shape was fixed" << endl;
266 TopoDS_Shape resFace = sfs->Shape();
268 else if(sfs->Status(ShapeExtend_FAIL)) {
269 cout<< "Shape could not be fixed" << endl;
271 else if(sfs->Status(ShapeExtent_OK)) {
272 cout<< "Initial face is valid with specified precision ="<< precendl;
276 @subsubsection occt_shg_2_3_4 Repairing tool for solids
278 Class *ShapeFix_Solid* allows fixing solids and building a solid from a shell to obtain a valid solid with a finite volume. The tool *ShapeFix_Shell* is used for correction of shells belonging to a solid.
280 This tool has the following control flags:
281 * *FixShellMode* -- Mode for applying fixes of ShapeFix_Shell, True by default.
282 * *CreateOpenShellMode* -- If it is equal to true solids are created from open shells, else solids are created from closed shells only, False by default.
284 @subsubsection occt_shg_2_3_5 Repairing tool for shells
285 Class *ShapeFix_Shell* allows fixing wrong orientation of faces in a shell. It changes the orientation of faces in the shell so that all faces in the shell have coherent orientations. If it is impossible to orient all faces in the shell (like in case of Mebious tape), then a few manifold or non-manifold shells will be created depending on the specified Non-manifold mode. The *ShapeFix_Face* tool is used to correct faces in the shell.
286 This tool has the following control flags:
287 * *FixFaceMode* -- mode for applying the fixes of *ShapeFix_Face*, *True* by default.
288 * *FixOrientationMode* -- mode for applying a fix for the orientation of faces in the shell.
290 @subsubsection occt_shg_2_3_6 Repairing tool for faces
292 Class *ShapeFix_Face* allows fixing the problems connected with wires of a face. It allows controlling the creation of a face (adding wires), and fixing wires by means of tool *ShapeFix_Wire*.
293 When a wire is added to a face, it can be reordered and degenerated edges can be fixed. This is performed or not depending on the user-defined flags (by default, False).
294 The following fixes are available:
295 * fixing of wires orientation on the face. If the face has no wire, the natural bounds are computed. If the face is on a spherical surface and has two or more wires on it describing holes, the natural bounds are added. In case of a single wire, it is made to be an outer one. If the face has several wires, they are oriented to lay one outside another (if possible). If the supporting surface is periodic, 2D curves of internal wires can be shifted on integer number of periods to put them inside the outer wire.
296 * fixing the case when the face on the closed surface is defined by a set of closed wires, and the seam is missing (this is not valid in OCCT). In that case, these wires are connected by means of seam edges into the same wire.
298 This tool has the following control flags:
299 * *FixWireMode* -- mode for applying fixes of a wire, True by default.
300 * *FixOrientationMode* -- mode for orienting a wire to border a limited square, True by default.
301 * *FixAddNaturalBoundMode* -- mode for adding natural bounds to a face, False by default.
302 * *FixMissingSeamMode* -- mode to fix a missing seam, True by default. If True, tries to insert a seam.
303 * *FixSmallAreaWireMode* -- mode to fix a small-area wire, False by default. If True, drops wires bounding small areas.
307 TopoDS_Face face = ...;
308 TopoDS_Wire wire = ...;
310 //Creates a tool and adds a wire to the face
311 ShapeFix_Face sff (face);
314 //use method Perform to fix the wire and the face
317 //or make a separate fix for the orientation of wire on the face
318 sff.FixOrientation();
320 //Get the resulting face
321 TopoDS_Face newface = sff.Face();
324 @subsubsection occt_shg_2_3_7 Repairing tool for wires
326 Class *ShapeFix_Wire* allows fixing a wire. Its method *Perform()* performs all the available fixes in addition to the geometrical filling of gaps. The geometrical filling of gaps can be made with the help of the tool for fixing the wireframe of shape *ShapeFix_Wireframe*.
328 The fixing order and the default behavior of *Perform()* is as follows:
329 * Edges in the wire are reordered by *FixReorder*. Most of fixing methods expect edges in a wire to be ordered, so it is necessary to make call to *FixReorder()* before making any other fixes. Even if it is forbidden, the analysis of whether the wire is ordered or not is performed anyway.
330 * Small edges are removed by *FixSmall* .
331 * Edges in the wire are connected (topologically) by *FixConnected* (if the wire is ordered).
332 * Edges (3Dcurves and 2D curves) are fixed by *FixEdgeCurves* (without *FixShifted* if the wire is not ordered).
333 * Degenerated edges are added by *FixDegenerated*(if the wire is ordered).
334 * Self-intersection is fixed by *FixSelfIntersection* (if the wire is ordered and *ClosedMode* is True).
335 * Lacking edges are fixed by *FixLacking* (if the wire is ordered).
337 The flag *ClosedWireMode* specifies whether the wire is (or should be) closed or not. If that flag is True (by default), fixes that require or force connection between edges are also executed for the last and the first edges.
339 The fixing methods can be turned on/off by using their corresponding control flags:
342 * *FixConnectedMode,*
343 * *FixEdgeCurvesMode,*
344 * *FixDegeneratedMode,*
345 * *FixSelfIntersectionMode*
347 Some fixes can be made in three ways:
348 * Increasing the tolerance of an edge or a vertex.
349 * Changing topology (adding/removing/replacing an edge in the wire and/or replacing the vertex in the edge, copying the edge etc.).
350 * Changing geometry (shifting a vertex or adjusting ends of an edge curve to vertices, or recomputing a 3D curve or 2D curves of the edge).
352 When it is possible to make a fix in more than one way (e.g., either by increasing the tolerance or shifting a vertex), it is chosen according to the user-defined flags:
353 * *ModifyTopologyMode* -- allows modifying topology, False by default.
354 * *ModifyGeometryMode* -- allows modifying geometry. Now this flag is used only in fixing self-intersecting edges (allows to modify 2D curves) and is True by default.
356 #### Fixing disordered edges
358 *FixReorder* is necessary for most other fixes (but is not necessary for Open CASCADE Technology). It checks whether edges in the wire go in a sequential order (the end of a preceding edge is the start of a following one). If it is not so, an attempt to reorder the edges is made.
360 #### Fixing small edges
362 *FixSmall* method searches for the edges, which have a length less than the given value (degenerated edges are ignored). If such an edge is found, it is removed provided that one of the following conditions is satisfied:
363 * both end vertices of that edge are one and the same vertex,
364 * end vertices of the edge are different, but the flag *ModifyTopologyMode* is True. In the latter case, method *FixConnected* is applied to the preceding and the following edges to ensure their connection.
366 #### Fixing disconnected edges
368 *FixConnected* method forces two adjacent edges to share the same common vertex (if they do not have a common one). It checks whether the end vertex of the preceding edge coincides with the start vertex of the following edge with the given precision, and then creates a new vertex and sets it as a common vertex for the fixed edges. At that point, edges are copied, hence the wire topology is changed (regardless of the *ModifyTopologyMode* flag). If the vertices do not coincide, this method fails.
370 #### Fixing the consistency of edge curves
372 *FixEdgeCurves* method performs a set of fixes dealing with 3D curves and 2D curves of edges in a wire.
374 These fixes will be activated with the help of a set of fixes from the repairing tool for edges called *ShapeFix_Edge*. Each of these fixes can be forced or forbidden by means of setting the corresponding flag to either True or False.
376 The mentioned fixes and the conditions of their execution are:
377 * fixing a disoriented 2D curve by call to *ShapeFix_Edge::FixReversed2d* -- if not forbidden by flag *FixReversed2dMode*;
378 * removing a wrong 2D curve by call to *ShapeFix_Edge::FixRemovePCurve* -- only if forced by flag *FixRemovePCurveMode*;
379 * fixing a missing 2D curve by call to *ShapeFix_Edge::FixAddPCurve* -- if not forbidden by flag *FixAddPCurveMode*;
380 * removing a wrong 3D curve by call to *ShapeFix_Edge::FixRemoveCurve3d* -- only if forced by flag *FixRemoveCurve3dMode*;
381 * fixing a missing 3D curve by call to *ShapeFix_Edge::FixAddCurve3d* -- if not forbidden by flag *FixAddCurve3dMode*;
382 * fixing 2D curves of seam edges -- if not forbidden by flag *FixSeamMode*;
383 * fixing 2D curves which can be shifted at an integer number of periods on the closed surface by call to *ShapeFix_Edge::FixShifted* -- if not forbidden by flag *FixShiftedMode*.
385 This fix is required if 2D curves of some edges in a wire lying on a closed surface were recomputed from 3D curves. In that case, the 2D curve for the edge, which goes along the seam of the surface, can be incorrectly shifted at an integer number of periods. The method *FixShifted* detects such cases and shifts wrong 2D curves back, ensuring that the 2D curves of the edges in the wire are connected.
387 * fixing the SameParameter problem by call to *ShapeFix_Edge::FixSameParameter* -- if not forbidden by flag *FixSameParameterMode*.
390 #### Fixing degenerated edges
392 *FixDegenerated* method checks whether an edge in a wire lies on a degenerated point of the supporting surface, or whether there is a degenerated point between the edges. If one of these cases is detected for any edge, a new degenerated edge is created and it replaces the current edge in the first case or is added to the wire in the second case. The newly created degenerated edge has a straight 2D curve, which goes from the end of the 2D curve of the preceding edge to the start of the following one.
394 #### Fixing intersections of 2D curves of the edges
396 *FixSelfIntersection* method detects and fixes the following problems:
397 * self-intersection of 2D curves of individual edges. If the flag *ModifyGeometryMode()* is False this fix will be performed by increasing the tolerance of one of end vertices to a value less then *MaxTolerance()*.
398 * intersection of 2D curves of each of the two adjacent edges (except the first and the last edges if the flag ClosedWireMode is False). If such intersection is found, the common vertex is modified in order to comprise the intersection point. If the flag *ModifyTopologyMode* is False this fix will be performed by increasing the tolerance of the vertex to a value less then *MaxTolerance()*.
399 * intersection of 2D curves of non-adjacent edges. If such intersection is found the tolerance of the nearest vertex is increased to comprise the intersection point. If such increase cannot be done with a tolerance less than *MaxTolerance* this fix will not be performed.
401 #### Fixing a lacking edge
403 *FixLacking* method checks whether a wire is not closed in the parametric space of the surface (while it can be closed in 3D). This is done by checking whether the gap between 2D curves of each of the two adjacent edges in the wire is smaller than the tolerance of the corresponding vertex. The algorithm computes the gap between the edges, analyses positional relationship of the ends of these edges and (if possible) tries to insert a new edge into the gap or increases the tolerance.
405 #### Fixing gaps in 2D and 3D wire by geometrical filling
406 The following methods check gaps between the ends of 2D or 3D curves of adjacent edges:
407 * Method *FixGap2d* moves the ends of 2D curves to the middle point.
408 * Method *FixGaps3d* moves the ends of 3D curves to a common vertex.
410 Boolean flag *FixGapsByRanges* is used to activate an additional mode applied before converting to B-Splines. When this mode is on, methods try to find the most precise intersection of curves, or the most precise projection of a target point, or an extremity point between two curves (to modify their parametric range accordingly). This mode is off by default. Independently of the additional mode described above, if gaps remain, these methods convert curves to B-Spline form and shift their ends if a gap is detected.
412 #### Example: A custom set of fixes
415 Let us create a custom set of fixes as an example.
417 TopoDS_Face face = ...;
418 TopoDS_Wire wire = ...;
419 Standard_Real precision = 1e-04;
420 ShapeFix_Wire sfw (wire, face, precision);
421 //Creates a tool and loads objects into it
423 //Orders edges in the wire so that each edge starts at the end of the one before it.
425 //Forces all adjacent edges to share
427 Standard_Boolean LockVertex = Standard_True;
428 if (sfw.FixSmall (LockVertex, precision)) {
429 //Removes all edges which are shorter than the given precision and have the same vertex at both ends.
431 if (sfw.FixSelfIntersection()) {
432 //Fixes self-intersecting edges and intersecting adjacent edges.
433 cout <<"Wire was slightly self-intersecting. Repaired"<<endl;
435 if ( sfw.FixLacking ( Standard_False ) ) {
436 //Inserts edges to connect adjacent non-continuous edges.
438 TopoDS_Wire newwire = sfw.Wire();
439 //Returns the corrected wire
442 #### Example: Correction of a wire
444 Let us correct the following wire:
446 @figure{/user_guides/shape_healing/images/shape_healing_image013.png,"Initial shape",420}
448 It is necessary to apply the @ref occt_shg_3_1_2 "tools for the analysis of wire validity" to check that:
449 * the edges are correctly oriented;
450 * there are no edges that are too short;
451 * there are no intersecting adjacent edges;
452 and then immediately apply fixing tools.
455 TopoDS_Face face = ...;
456 TopoDS_Wire wire = ...;
457 Standard_Real precision = 1e-04;
458 ShapeAnalysis_Wire saw (wire, face, precision);
459 ShapeFix_Wire sfw (wire, face, precision);
460 if (saw.CheckOrder()) {
461 cout<<“Some edges in the wire need to be reordered”<<endl;
462 // Two edges are incorrectly oriented
464 cout<<“Reordering is done”<<endl;
466 // their orientation is corrected
467 if (saw.CheckSmall (precision)) {
468 cout<<“Wire contains edge(s) shorter than “<<precision<<endl;
469 // An edge that is shorter than the given tolerance is found.
470 Standard_Boolean LockVertex = Standard_True;
471 if (sfw.FixSmall (LockVertex, precision)) {
472 cout<<“Edges shorter than “<<precision<<“ have been removed”
474 //The edge is removed
477 if (saw.CheckSelfIntersection()) {
478 cout<<“Wire has self-intersecting or intersecting
479 adjacent edges”<<endl;
480 // Two intersecting adjacent edges are found.
481 if (sfw.FixSelfIntersection()) {
482 cout<<“Wire was slightly self-intersecting. Repaired”<<endl;
483 // The edges are cut at the intersection point so that they no longer intersect.
488 As the result all failures have been fixed.
490 @figure{/user_guides/shape_healing/images/shape_healing_image014.png,"Resulting shape",420}
492 @subsubsection occt_shg_2_3_8 Repairing tool for edges
494 Class *ShapeFix_Edge* provides tools for fixing invalid edges. The following geometrical and/or topological inconsistencies are detected and fixed:
495 * missing 3D curve or 2D curve,
496 * mismatching orientation of a 3D curve and a 2D curve,
497 * incorrect SameParameter flag (curve deviation is greater than the edge tolerance).
498 Each fixing method first checks whether the problem exists using methods of the *ShapeAnalysis_Edge* class. If the problem is not detected, nothing is done.
499 This tool does not have the method *Perform()*.
501 To see how this tool works, it is possible to take an edge, where the maximum deviation between the 3D curve and 2D curve P1 is greater than the edge tolerance.
503 @figure{/user_guides/shape_healing/images/shape_healing_image011.png,"Initial shape",420}
505 First it is necessary to apply the @ref occt_shg_3_1_3 "tool for checking the edge validity" to find that the maximum deviation between pcurve and 3D curve is greater than tolerance. Then we can use the repairing tool to increase the tolerance and make the deviation acceptable.
508 ShapeAnalysis_Edge sae;
509 TopoDS_Face face = ...;
510 TopoDS_Wire wire = ...;
511 Standard_Real precision = 1e-04;
513 Standard_Real maxdev;
514 if (sae.CheckSameParameter (edge, maxdev)) {
515 cout<<“Incorrect SameParameter flag”<<endl;
516 cout<<“Maximum deviation “<<maxdev<< “, tolerance “
517 <<BRep_Tool::Tolerance(edge)<<endl;
518 sfe.FixSameParameter();
519 cout<<“New tolerance “<<BRep_Tool::Tolerance(edge)<<endl;
523 @figure{/user_guides/shape_healing/images/shape_healing_image012.png,"Resulting shape",420}
525 As the result, the edge tolerance has been increased.
528 @subsubsection occt_shg_2_3_9 Repairing tool for the wireframe of a shape
530 Class *ShapeFix_Wireframe* provides methods for geometrical fixing of gaps and merging small edges in a shape. This class performs the following operations:
531 * fills gaps in the 2D and 3D wireframe of a shape.
532 * merges and removes small edges.
534 Fixing of small edges can be managed with the help of two flags:
535 * *ModeDropSmallEdges()* -- mode for removing small edges that can not be merged, by default it is equal to Standard_False.
536 * *LimitAngle* -- maximum possible angle for merging two adjacent edges, by default no limit angle is applied (-1).
537 To perform fixes it is necessary to:
538 * create a tool and initialize it by shape,
539 * set the working precision problems will be detected with and the maximum allowed tolerance
544 Handle(ShapeFix_Wireframe) sfwf = new ShapeFix_Wireframe(shape);
545 //sets the working precision problems will be detected with and the maximum allowed tolerance
546 sfwf->SetPrecision(prec);
547 sfwf->SetMaxTolerance(maxTol);
550 //fixing of small edges
551 //setting of the drop mode for the fixing of small edges and max possible angle between merged edges.
552 sfwf->ModeDropSmallEdges = Standard_True;
553 sfwf->SetLimliteAngle(angle);
555 sfwf->FixSmallEdges();
557 TopoDS_Shape resShape = sfwf->Shape();
560 It is desirable that a shape is topologically correct before applying the methods of this class.
562 @subsubsection occt_shg_2_3_10 Tool for removing small faces from a shape
564 Class ShapeFix_FixSmallFaceThis tool is intended for dropping small faces from the shape. The following cases are processed:
565 * Spot face: if the size of the face is less than the given precision;
566 * Strip face: if the size of the face in one dimension is less then the given precision.
568 The sequence of actions for performing the fix is the same as for the fixes described above:
572 Handle(ShapeFix_FixSmallFace) sff = new ShapeFix_FixSmallFace(shape);
573 //setting of tolerances
574 sff->SetPrecision(prec);
575 sff->SetMaxTolerance(maxTol);
579 TopoDS_Shape resShape = sff.FixShape();
582 @subsubsection occt_shg_2_3_11 Tool to modify tolerances of shapes (Class ShapeFix_ShapeTolerance).
584 This tool provides a functionality to set tolerances of a shape and its sub-shapes.
585 In Open CASCADE Technology only vertices, edges and faces have tolerances.
587 This tool allows processing each concrete type of sub-shapes or all types at a time.
588 You set the tolerance functionality as follows:
589 * set a tolerance for sub-shapes, by method SetTolerance,
590 * limit tolerances with given ranges, by method LimitTolerance.
594 ShapeFix_ShapeTolerance Sft;
595 //setting a specified tolerance on shape and all of its sub-shapes.
596 Sft.SetTolerance(shape,toler);
597 //setting a specified tolerance for vertices only
598 Sft.SetTolerance(shape,toler,TopAbs_VERTEX);
599 //limiting the tolerance on the shape and its sub-shapes between minimum and maximum tolerances
600 Sft.LimitTolerance(shape,tolermin,tolermax);
604 @section occt_shg_3 Analysis
606 @subsection occt_shg_3_1 Analysis of shape validity
608 The *ShapeAnalysis* package provides tools for the analysis of topological shapes.
609 It is not necessary to check a shape by these tools before the execution of repairing tools because these tools are used for the analysis before performing fixes inside the repairing tools.
610 However, if you want, these tools can be used for detecting some of shape problems independently from the repairing tools.
612 It can be done in the following way:
613 * create an analysis tool.
614 * initialize it by shape and set a tolerance problems will be detected with if it is necessary.
615 * check the problem that interests you.
618 TopoDS_Face face = ...;
619 ShapeAnalysis_Edge sae;
620 //Creates a tool for analyzing an edge
621 for(TopExp_Explorer Exp(face,TopAbs_EDGE);Exp.More();Exp.Next()) {
622 TopoDS_Edge edge = TopoDS::Edge (Exp.Current());
623 if (!sae.HasCurve3d (edge)) {
624 cout <<"Edge has no 3D curve"<< endl; }
628 @subsubsection occt_shg_3_1_1 Analysis of orientation of wires on a face.
630 It is possible to check whether a face has an outer boundary with the help of method *ShapeAnalysis::IsOuterBound*.
633 TopoDS_Face face … //analyzed face
634 if(!ShapeAnalysis::IsOuterBound(face)) {
635 cout<<"Face has not outer boundary"<<endl;
639 @subsubsection occt_shg_3_1_2 Analysis of wire validity
641 Class *ShapeAnalysis_Wire* is intended to analyze a wire. It provides functionalities both to explore wire properties and to check its conformance to Open CASCADE Technology requirements.
642 These functionalities include:
643 * checking the order of edges in the wire,
644 * checking for the presence of small edges (with a length less than the given value),
645 * checking for the presence of disconnected edges (adjacent edges having different vertices),
646 * checking the consistency of edge curves,
647 * checking for the presence or missing of degenerated edges,
648 * checking for the presence of self-intersecting edges and intersecting edges (edges intersection is understood as intersection of their 2D curves),
649 * checking for lacking edges to fill gaps in the surface parametric space,
650 * analyzing the wire orientation (to define the outer or the inner bound on the face),
651 * analyzing the orientation of the shape (edge or wire) being added to an already existing wire.
653 **Note** that all checking operations except for the first one are based on the assumption that edges in the wire are ordered. Thus, if the wire is detected as non-ordered it is necessary to order it before calling other checking operations. This can be done, for example, with the help of the *ShapeFix_Wire::FixOrder()* method.
655 This tool should be initialized with wire, face (or a surface with a location) or precision.
656 Once the tool has been initialized, it is possible to perform the necessary checking operations. In order to obtain all information on a wire at a time the global method *Perform* is provided. It calls all other API checking operations to check each separate case.
658 API methods check for corresponding cases only, the value and the status they return can be analyzed to understand whether the case was detected or not.
660 Some methods in this class are:
661 * *CheckOrder* checks whether edges in the wire are in the right order
662 * *CheckConnected* checks whether edges are disconnected
663 * *CheckSmall* checks whether there are edges that are shorter than the given value
664 * *CheckSelfIntersection* checks, whether there are self-intersecting or adjacent intersecting edges. If the intersection takes place due to nonadjacent edges, it is not detected.
666 This class maintains status management. Each API method stores the status of its last execution which can be queried by the corresponding *Status..()* method. In addition, each API method returns a Boolean value, which is True when a case being analyzed is detected (with the set *ShapeExtend_DONE* status), otherwise it is False.
669 TopoDS_Face face = ...;
670 TopoDS_Wire wire = ...;
671 Standard_Real precision = 1e-04;
672 ShapeAnalysis_Wire saw (wire, face, precision);
673 //Creates a tool and loads objects into it
674 if (saw.CheckOrder()) {
675 cout<<"Some edges in the wire need to be reordered"<<endl;
676 cout<<"Please ensure that all the edges are correctly ordered before further analysis"<<endl;
679 if (saw.CheckSmall (precision)) {
680 cout<<"Wire contains edge(s) shorter than "<<precisionendl;
682 if (saw.CheckConnected()) {
683 cout<<"Wire is disconnected"<<endl;
685 if (saw.CheckSelfIntersection()) {
686 cout<<"Wire has self-intersecting or intersecting adjacent edges"<< endl;
690 @subsubsection occt_shg_3_1_3 Analysis of edge validity
692 Class *ShapeAnalysis_Edge* is intended to analyze edges. It provides the following functionalities to work with an edge:
693 * querying geometrical representations (3D curve and pcurve(s) on a given face or surface),
694 * querying topological sub-shapes (bounding vertices),
695 * checking overlapping edges,
696 * analyzing the curves consistency:
697 + mutual orientation of the 3D curve and 2D curve (co-directions or opposite directions),
698 + correspondence of 3D and 2D curves to vertices.
700 This class supports status management described above.
703 TopoDS_Face face = ...;
704 ShapeAnalysis_Edge sae;
705 //Creates a tool for analyzing an edge
706 for(TopExp_Explorer Exp(face,TopAbs_EDGE);Exp.More();Exp.Next()) {
707 TopoDS_Edge edge = TopoDS::Edge (Exp.Current());
708 if (!sae.HasCurve3d (edge)) {
709 cout << "Edge has no 3D curve" << endl;
711 Handle(Geom2d_Curve) pcurve;
712 Standard_Real cf, cl;
713 if (sae.PCurve (edge, face, pcurve, cf, cl, Standard_False)) {
714 //Returns the pcurve and its range on the given face
715 cout<<"Pcurve range ["<<cf<<", "<<cl<<"]"<< endl;
717 Standard_Real maxdev;
718 if (sae.CheckSameParameter (edge, maxdev)) {
719 //Checks the consistency of all the curves in the edge
720 cout<<"Incorrect SameParameter flag"<<endl;
722 cout<<"Maximum deviation "<<maxdev<<", tolerance"
723 <<BRep_Tool::Tolerance(edge)<<endl;
725 //checks the overlapping of two edges
726 if(sae.CheckOverlapping(edge1,edge2,prec,dist)) {
727 cout<<"Edges are overlapped with tolerance = "<<prec<<endl;
728 cout<<"Domain of overlapping ="<<dist<<endl;
732 @subsubsection occt_shg_3_1_4 Analysis of presence of small faces
734 Class *ShapeAnalysis_CheckSmallFace* class is intended for analyzing small faces from the shape using the following methods:
735 * *CheckSpotFace()* checks if the size of the face is less than the given precision;
736 * *CheckStripFace* checks if the size of the face in one dimension is less than the given precision.
739 TopoDS_Shape shape … // checked shape
741 ShapeAnalysis_CheckSmallFace saf;
742 //exploring the shape on faces and checking each face
743 Standard_Integer numSmallfaces =0;
744 for(TopExp_Explorer aExp(shape,TopAbs_FACE); aExp.More(); aExp.Next()) {
745 TopoDS_Face face = TopoDS::Face(aexp.Current());
747 if(saf.CheckSpotFace(face,prec) ||
748 saf.CheckStripFace(face,E1,E2,prec))
752 cout<<"Number of small faces in the shape ="<< numSmallfaces <<endl;
755 @subsubsection occt_shg_3_1_5 Analysis of shell validity and closure
757 Class *ShapeAnalysis_Shell* allows checking the orientation of edges in a manifold shell. With the help of this tool, free edges (edges entered into one face) and bad edges (edges entered into the shell twice with the same orientation) can be found. By occurrence of bad and free edges a conclusion about the shell validity and the closure of the shell can be made.
760 TopoDS_Shell shell // checked shape
761 ShapeAnalysis_Shell sas(shell);
762 //analysis of the shell , second parameter is set to True for //getting free edges,(default False)
763 sas.CheckOrientedShells(shell,Standard_True);
764 //getting the result of analysis
765 if(sas.HasBadEdges()) {
766 cout<<"Shell is invalid"<<endl;
767 TopoDS_Compound badEdges = sas.BadEdges();
769 if(sas.HasFreeEdges()) {
770 cout<<"Shell is open"<<endl;
771 TopoDS_Compound freeEdges = sas.FreeEdges();
775 @subsection occt_shg_3_2 Analysis of shape properties.
776 @subsubsection occt_shg_3_2_1 Analysis of tolerance on shape
778 Class *ShapeAnalysis_ShapeTolerance* allows computing tolerances of the shape and its sub-shapes. In Open CASCADE Technology only vertices, edges and faces have tolerances:
780 This tool allows analyzing each concrete type of sub-shapes or all types at a time.
781 The analysis of tolerance functionality is the following:
782 * computing the minimum, maximum and average tolerances of sub-shapes,
783 * finding sub-shapes with tolerances exceeding the given value,
784 * finding sub-shapes with tolerances in the given range.
787 TopoDS_Shape shape = ...;
788 ShapeAnalysis_ShapeTolerance sast;
789 Standard_Real AverageOnShape = sast.Tolerance (shape, 0);
790 cout<<"Average tolerance of the shape is "<<AverageOnShape<<endl;
791 Standard_Real MinOnEdge = sast.Tolerance (shape,-1,TopAbs_EDGE);
792 cout<<"Minimum tolerance of the edges is "<<MinOnEdge<<endl;
793 Standard_Real MaxOnVertex = sast.Tolerance (shape,1,TopAbs_VERTEX);
794 cout<<"Maximum tolerance of the vertices is "<<MaxOnVertex<<endl;
795 Standard_Real MaxAllowed = 0.1;
796 if (MaxOnVertex > MaxAllowed) {
797 cout<<"Maximum tolerance of the vertices exceeds maximum allowed"<<endl;
801 @subsubsection occt_shg_3_2_2 Analysis of free boundaries.
803 Class ShapeAnalysis_FreeBounds is intended to analyze and output the free bounds of a shape. Free bounds are wires consisting of edges referenced only once by only one face in the shape.
804 This class works on two distinct types of shapes when analyzing their free bounds:
805 * Analysis of possible free bounds taking the specified tolerance into account. This analysis can be applied to a compound of faces. The analyzer of the sewing algorithm (*BRepAlgo_Sewing*) is used to forecast what free bounds would be obtained after the sewing of these faces is performed. The following method should be used for this analysis:
807 ShapeAnalysis_FreeBounds safb(shape,toler);
809 * Analysis of already existing free bounds. Actual free bounds (edges shared by the only face in the shell) are output in this case. *ShapeAnalysis_Shell* is used for that.
811 ShapeAnalysis_FreeBounds safb(shape);
814 When connecting edges into wires this algorithm tries to build wires of maximum length. Two options are provided for the user to extract closed sub-contours out of closed and/or open contours. Free bounds are returned as two compounds, one for closed and one for open wires. To obtain a result it is necessary to use methods:
816 TopoDS_Compound ClosedWires = safb.GetClosedWires();
817 TopoDS_Compound OpenWires = safb.GetOpenWires();
819 This class also provides some static methods for advanced use: connecting edges/wires to wires, extracting closed sub-wires from wires, distributing wires into compounds for closed and open wires.
822 TopoDS_Shape shape = ...;
823 Standard_Real SewTolerance = 1.e-03;
824 //Tolerance for sewing
825 Standard_Boolean SplitClosed = Standard_False;
826 Standard_Boolean SplitOpen = Standard_True;
827 //in case of analysis of possible free boundaries
828 ShapeAnalysis_FreeBounds safb (shape, SewTolerance,
829 SplitClosed, SplitOpen);
830 //in case of analysis of existing free bounds
831 ShapeAnalysis_FreeBounds safb (shape, SplitClosed, SplitOpen);
832 //getting the results
833 TopoDS_Compound ClosedWires = safb.GetClosedWires();
834 //Returns a compound of closed free bounds
835 TopoDS_Compound OpenWires = safb.GetClosedWires();
836 //Returns a compound of open free bounds
839 @subsubsection occt_shg_3_2_3 Analysis of shape contents
841 Class *ShapeAnalysis_ShapeContents* provides tools counting the number of sub-shapes and selecting a sub-shape by the following criteria:
843 Methods for getting the number of sub-shapes:
848 * number of vertices.
850 Methods for calculating the number of geometrical objects or sub-shapes with a specified type:
851 * number of free faces,
852 * number of free wires,
853 * number of free edges,
854 * number of C0 surfaces,
855 * number of C0 curves,
856 * number of BSpline surfaces,… etc
858 and selecting sub-shapes by various criteria.
860 The corresponding flags should be set to True for storing a shape by a specified criteria:
861 * faces based on indirect surfaces -- *safc.MofifyIndirectMode() = Standard_True*;
862 * faces based on offset surfaces -- *safc.ModifyOffsetSurfaceMode() = Standard_True*;
863 * edges if their 3D curves are trimmed -- *safc.ModifyTrimmed3dMode() = Standard_True*;
864 * edges if their 3D curves and 2D curves are offset curves -- *safc.ModifyOffsetCurveMode() = Standard_True*;
865 * edges if their 2D curves are trimmed -- *safc.ModifyTrimmed2dMode() = Standard_True*;
867 Let us, for example, select faces based on offset surfaces.
870 ShapeAnalysis_ShapeContents safc;
871 //set a corresponding flag for storing faces based on the offset surfaces
872 safc.ModifyOffsetSurfaceMode() = Standard_True;
874 //getting the number of offset surfaces in the shape
875 Standard_Integer NbOffsetSurfaces = safc.NbOffsetSurf();
876 //getting the sequence of faces based on offset surfaces.
877 Handle(TopTools_HSequenceOfShape) seqFaces = safc.OffsetSurfaceSec();
880 @section occt_shg_4 Upgrading
882 Upgrading tools are intended for adaptation of shapes for better use by Open CASCADE Technology or for customization to particular needs, i.e. for export to another system. This means that not only it corrects and upgrades but also changes the definition of a shape with regard to its geometry, size and other aspects. Convenient API allows you to create your own tools to perform specific upgrading. Additional tools for particular cases provide an ability to divide shapes and surfaces according to certain criteria.
884 @subsection occt_shg_4_1 Tools for splitting a shape according to a specified criterion
886 @subsubsection occt_shg_4_1_1 Overview
888 These tools provide such modifications when one topological object can be divided or converted to several ones according to specified criteria. Besides, there are high level API tools for particular cases which:
889 * Convert the geometry of shapes up to a given continuity,
890 * split revolutions by U to segments less than the given value,
891 * convert to Bezier surfaces and Bezier curves,
892 * split closed faces,
893 * convert C0 BSpline curve to a sequence of C1 BSpline curves.
895 All tools for particular cases are based on general tools for shape splitting but each of them has its own tools for splitting or converting geometry in accordance with the specified criteria.
897 General tools for shape splitting are:
898 * tool for splitting the whole shape,
899 * tool for splitting a face,
900 * tool for splitting wires.
902 Tools for shape splitting use tools for geometry splitting:
903 * tool for splitting surfaces,
904 * tool for splitting 3D curves,
905 * tool for splitting 2D curves.
907 @subsubsection occt_shg_4_1_2 Using tools available for shape splitting.
908 If it is necessary to split a shape by a specified continuity, split closed faces in the shape, split surfaces of revolution in the shape by angle or to convert all surfaces, all 3D curves, all 2D curves in the shape to Bezier, it is possible to use the existing/available tools.
910 The usual way to use these tools exception for the tool of converting a C0 BSpline curve is the following:
911 * a tool is created and initialized by shape.
912 * work precision for splitting and the maximum allowed tolerance are set
913 * the value of splitting criterion Is set (if necessary)
914 * splitting is performed.
915 * splitting statuses are obtained.
917 * the history of modification of the initial shape and its sub-shapes is output (this step is optional).
919 Let us, for example, split all surfaces and all 3D and 2D curves having a continuity of less the C2.
922 //create a tool and initializes it by shape.
923 ShapeUpgrade_ShapeDivideContinuity ShapeDivedeCont(initShape);
925 //set the working 3D and 2D precision and the maximum allowed //tolerance
926 ShapeDivideCont.SetTolerance(prec);
927 ShapeDivideCont.SetTolerance2D(prec2d);
928 ShapeDivideCont.SetMaxTolerance(maxTol);
930 //set the values of criteria for surfaces, 3D curves and 2D curves.
931 ShapeDivideCont.SetBoundaryCriterion(GeomAbs_C2);
932 ShapeDivideCont.SetPCurveCriterion(GeomAbs_C2);
933 ShapeDivideCont.SetSurfaceCriterion(GeomAbs_C2);
935 //perform the splitting.
936 ShapeDivideCont.Perform();
938 //check the status and gets the result
939 if(ShapeDivideCont.Status(ShapeExtend_DONE)
940 TopoDS_Shape result = ShapeDivideCont.GetResult();
941 //get the history of modifications made to faces
942 for(TopExp_Explorer aExp(initShape,TopAbs_FACE); aExp.More(0; aExp.Next()) {
943 TopoDS_Shape modifShape = ShapeDivideCont.GetContext()-> Apply(aExp.Current());
947 @subsubsection occt_shg_4_1_3 Creation of a new tool for splitting a shape.
948 To create a new splitting tool it is necessary to create tools for geometry splitting according to a desirable criterion. The new tools should be inherited from basic tools for geometry splitting. Then the new tools should be set into corresponding tools for shape splitting.
949 * a new tool for surface splitting should be set into the tool for face splitting
950 * new tools for splitting of 3D and 2D curves should be set into the splitting tool for wires.
952 To change the value of criterion of shape splitting it is necessary to create a new tool for shape splitting that should be inherited from the general splitting tool for shapes.
954 Let us split a shape according to a specified criterion.
957 //creation of new tools for geometry splitting by a specified criterion.
958 Handle(MyTools_SplitSurfaceTool) MySplitSurfaceTool = new MyTools_SplitSurfaceTool;
959 Handle(MyTools_SplitCurve3DTool) MySplitCurve3Dtool = new MyTools_SplitCurve3DTool;
960 Handle(MyTools_SplitCurve2DTool) MySplitCurve2Dtool = new MyTools_SplitCurve2DTool;
962 //creation of a tool for splitting the shape and initialization of that tool by shape.
963 TopoDS_Shape initShape
964 MyTools_ShapeDivideTool ShapeDivide (initShape);
966 //setting of work precision for splitting and maximum allowed tolerance.
967 ShapeDivide.SetPrecision(prec);
968 ShapeDivide.SetMaxTolerance(MaxTol);
970 //setting of new splitting geometry tools in the shape splitting tools
971 Handle(ShapeUpgrade_FaceDivide) FaceDivide = ShapeDivide->GetSplitFaceTool();
972 Handle(ShapeUpgrade_WireDivide) WireDivide = FaceDivide->GetWireDivideTool();
973 FaceDivide->SetSplitSurfaceTool(MySplitSurfaceTool);
974 WireDivide->SetSplitCurve3dTool(MySplitCurve3DTool);
975 WireDivide->SetSplitCurve2dTool(MySplitCurve2DTool);
977 //setting of the value criterion.
978 ShapeDivide.SetValCriterion(val);
981 ShapeDivide.Perform();
984 TopoDS_Shape splitShape = ShapeDivide.GetResult();
986 //getting the history of modifications of faces
987 for(TopExp_Explorer aExp(initShape,TopAbs_FACE); aExp.More(0; aExp.Next()) {
988 TopoDS_Shape modifShape = ShapeDivide.GetContext()-> Apply(aExp.Current());
992 @subsection occt_shg_4_2 General splitting tools.
994 @subsubsection occt_shg_4_2_1 General tool for shape splitting
996 Class *ShapeUpgrade_ShapeDivide* provides shape splitting and converting according to the given criteria. It performs these operations for each face with the given tool for face splitting (*ShapeUpgrade_FaceDivide* by default).
998 This tool provides access to the tool for dividing faces with the help of the methods *SetSplitFaceTool* and *GetSpliFaceTool.*
1000 @subsubsection occt_shg_4_2_2 General tool for face splitting
1002 Class *ShapeUpgrade_FaceDivide* divides a Face (edges in the wires, by splitting 3D and 2D curves, as well as the face itself, by splitting the supporting surface) according to the given criteria.
1004 The area of the face intended for division is defined by 2D curves of the wires on the Face.
1005 All 2D curves are supposed to be defined (in the parametric space of the supporting surface).
1006 The result is available after the call to the *Perform* method. It is a Shell containing all resulting Faces. All modifications made during the splitting operation are recorded in the external context (*ShapeBuild_ReShape*).
1008 This tool provides access to the tool for wire division and surface splitting by means of the following methods:
1009 * *SetWireDivideTool,*
1010 * *GetWireDivideTool,*
1011 * *SetSurfaceSplitTool,*
1012 * *GetSurfaceSplitTool*.
1014 @subsubsection occt_shg_4_2_3 General tool for wire splitting
1015 Class *ShapeUpgrade_WireDivide* divides edges in the wire lying on the face or free wires or free edges with a given criterion. It splits the 3D curve and 2D curve(s) of the edge on the face. Other 2D curves, which may be associated with the edge, are simply copied. If the 3D curve is split then the 2D curve on the face is split as well, and vice-versa. The original shape is not modified. Modifications made are recorded in the context (*ShapeBuild_ReShape*).
1017 This tool provides access to the tool for dividing and splitting 3D and 2D curves by means of the following methods:
1018 * *SetEdgeDivdeTool,*
1019 * *GetEdgeDivideTool,*
1020 * *SetSplitCurve3dTool,*
1021 * *GetSplitCurve3dTool,*
1022 * *SetSplitCurve2dTool,*
1023 * *GetSplitCurve2dTool*
1025 and it also provides access to the mode for splitting edges by methods *SetEdgeMode* and *GetEdgeMode*.
1027 This mode sets whether only free edges, only shared edges or all edges are split.
1029 @subsubsection occt_shg_4_2_4 General tool for edge splitting
1031 Class *ShapeUpgrade_EdgeDivide* divides edges and their geometry according to the specified criteria. It is used in the wire-dividing tool.
1033 This tool provides access to the tool for dividing and splitting 3D and 2D curves by the following methods:
1034 * *SetSplitCurve3dTool,*
1035 * *GetSplitCurve3dTool,*
1036 * *SetSplitCurve2dTool,*
1037 * *GetSplitCurve2dTool*.
1039 @subsubsection occt_shg_4_2_5 General tools for geometry splitting
1041 There are three general tools for geometry splitting.
1042 * General tool for surface splitting.(*ShapeUpgrade_SplitSurface*)
1043 * General tool for splitting 3D curves.(*ShapeUpgrade_SplitCurve3d*)
1044 * General tool for splitting 2D curves.(*ShapeUpgrade_SplitCurve2d*)
1046 All these tools are constructed the same way:
1048 * for initializing by geometry (method *Init*)
1049 * for splitting (method *Perform*)
1050 * for getting the status after splitting and the results:
1051 + *Status* -- for getting the result status;
1052 + *ResSurface* -- for splitting surfaces;
1053 + *GetCurves* -- for splitting 3D and 2D curves.
1054 During the process of splitting in the method *Perform* :
1055 * splitting values in the parametric space are computed according to a specified criterion (method *Compute*)
1056 * splitting is made in accordance with the values computed for splitting (method *Build*).
1058 To create new tools for geometry splitting it is enough to inherit a new tool from the general tool for splitting a corresponding type of geometry and to redefine the method for computation of splitting values according to the specified criterion in them. (method *Compute*).
1060 Header file for the tool for surface splitting by continuity:
1063 class ShapeUpgrade_SplitSurfaceContinuity : public ShapeUpgrade_SplitSurface {
1064 Standard_EXPORT ShapeUpgrade_SplitSurfaceContinuity();
1066 //methods to set the criterion and the tolerance into the splitting tool
1067 Standard_EXPORT void SetCriterion(const GeomAbs_Shape Criterion) ;
1068 Standard_EXPORT void SetTolerance(const Standard_Real Tol) ;
1070 //redefinition of method Compute
1071 Standard_EXPORT virtual void Compute(const Standard_Boolean Segment) ;
1072 Standard_EXPORT ~ShapeUpgrade_SplitSurfaceContinuity();
1074 GeomAbs_Shape myCriterion;
1075 Standard_Real myTolerance;
1076 Standard_Integer myCont;
1080 @subsection occt_shg_4_3 Specific splitting tools.
1082 @subsubsection occt_shg_4_3_1 Conversion of shape geometry to the target continuity
1083 Class *ShapeUpgrade_ShapeDivideContinuity* allows converting geometry with continuity less than the specified continuity to geometry with target continuity. If converting is not possible than geometrical object is split into several ones, which satisfy the given criteria. A topological object based on this geometry is replaced by several objects based on the new geometry.
1086 ShapeUpgrade_ShapeDivideContinuity sdc (shape);
1087 sdc.SetTolerance (tol3d);
1088 sdc.SetTolerance3d (tol2d); // if known, else 1.e-09 is taken
1089 sdc.SetBoundaryCriterion (GeomAbs_C2); // for Curves 3D
1090 sdc.SetPCurveCriterion (GeomAbs_C2); // for Curves 2D
1091 sdc.SetSurfaceCriterion (GeomAbs_C2); // for Surfaces
1093 TopoDS_Shape bshape = sdc.Result();
1094 //.. to also get the correspondances before/after
1095 Handle(ShapeBuild_ReShape) ctx = sdc.Context();
1096 //.. on a given shape
1097 if (ctx.IsRecorded (sh)) {
1098 TopoDS_Shape newsh = ctx->Value (sh);
1099 // if there are several results, they are recorded inside a Compound.
1100 // .. process as needed
1104 @subsubsection occt_shg_4_3_2 Splitting by angle
1105 Class *ShapeUpgrade_ShapeDivideAngle* allows splitting all surfaces of revolution, cylindrical, toroidal, conical, spherical surfaces in the given shape so that each resulting segment covers not more than the defined angle (in radians).
1107 @subsubsection occt_shg_4_3_3 Conversion of 2D, 3D curves and surfaces to Bezier
1109 Class *ShapeUpgrade_ShapeConvertToBezier* is an API tool for performing a conversion of 3D, 2D curves to Bezier curves and surfaces to Bezier based surfaces (Bezier surface, surface of revolution based on Bezier curve, offset surface based on any of previous types).
1111 This tool provides access to various flags for conversion of different types of curves and surfaces to Bezier by methods:
1113 * *Set3dConversion,*
1114 * *Get3dConversion,*
1115 * *Set3dLineConversion,*
1116 * *Get3dLineConversion,*
1117 * *Set3dCircleConversion,*
1118 * *Get3dCircleConversion,*
1119 * *Set3dConicConversion,*
1120 * *Get3dConicConversion*
1122 * *Set2dConversion,*
1125 * *GetSurfaceConversion,*
1128 * *SetRevolutionMode,*
1129 * *GetRevolutionMode,*
1130 * *SetExtrusionMode,*
1131 * *GetExtrusionMode,*
1135 Let us attempt to produce a conversion of planes to Bezier surfaces.
1137 //Creation and initialization of a tool.
1138 ShapeUpgrade_ShapeConvertToBezier SCB (Shape);
1139 //setting tolerances
1141 //setting mode for conversion of planes
1142 SCB.SetSurfaceConversion (Standard_True);
1143 SCB.SetPlaneMode(Standard_True);
1145 If(SCB.Status(ShapeExtend_DONE)
1146 TopoDS_Shape result = SCB.GetResult();
1149 @subsubsection occt_shg_4_3_4 Tool for splitting closed faces
1151 Class *ShapeUpgrade_ShapeDivideClosed* provides splitting of closed faces in the shape to a defined number of components by the U and V parameters. It topologically and (partially) geometrically processes closed faces and performs splitting with the help of class *ShapeUpgrade_ClosedFaceDivide*.
1154 TopoDS_Shape aShape = …;
1155 ShapeUpgrade_ShapeDivideClosed tool (aShape );
1156 Standard_Real closeTol = …;
1157 tool.SetPrecision(closeTol);
1158 Standard_Real maxTol = …;
1159 tool.SetMaxTolerance(maxTol);
1160 Standard_Integer NbSplitPoints = …;
1161 tool.SetNbSplitPoints(num);
1162 if ( ! tool.Perform() && tool.Status (ShapeExtend_FAIL) ) {
1163 cout<<"Splitting of closed faces failed"<<endl;
1166 TopoDS_Shape aResult = tool.Result();
1169 @subsubsection occt_shg_4_3_5 Tool for splitting a C0 BSpline 2D or 3D curve to a sequence C1 BSpline curves
1171 The API methods for this tool is a package of methods *ShapeUpgrade::C0BSplineToSequenceOfC1BsplineCurve*, which converts a C0 B-Spline curve into a sequence of C1 B-Spline curves. This method splits a B-Spline at the knots with multiplicities equal to degree, it does not use any tolerance and therefore does not change the geometry of the B-Spline. The method returns True if C0 B-Spline was successfully split, otherwise returns False (if BS is C1 B-Spline).
1173 @subsubsection occt_shg_4_3_6 Tool for splitting faces
1175 *ShapeUpgrade_ShapeDivideArea* can work with compounds, solids, shells and faces.
1176 During the work this tool examines each face of a specified shape and if the face area exceeds the specified maximal area, this face is divided. Face splitting is performed in the parametric space of this face. The values of splitting in U and V directions are calculated with the account of translation of the bounding box form parametric space to 3D space.
1178 Such calculations are necessary to avoid creation of strip faces. In the process of splitting the holes on the initial face are taken into account. After the splitting all new faces are checked by area again and the splitting procedure is repeated for the faces whose area still exceeds the max allowed area. Sharing between faces in the shape is preserved and the resulting shape is of the same type as the source shape.
1180 An example of using this tool is presented in the figures below:
1182 @figure{/user_guides/shape_healing/images/shape_healing_image003.png,"Source Face",240}
1184 @figure{/user_guides/shape_healing/images/shape_healing_image004.png,"Resulting shape",240}
1187 *ShapeUpgrade_ShapeDivideArea* is inherited from the base class *ShapeUpgrade_ShapeDivide* and should be used in the following way:
1188 * This class should be initialized on a shape with the help of the constructor or method *Init()* from the base class.
1189 * The maximal allowed area should be specified by the method *MaxArea()*.
1190 * To produce a splitting use method Perform from the base class.
1191 * The result shape can be obtained with the help the method *Result()*.
1194 ShapeUpgrade_ShapeDivideArea tool (inputShape);
1195 tool.MaxArea() = aMaxArea;
1197 if(tool.Status(ShapeExtend_DONE)) {
1198 TopoDS_Shape ResultShape = tool.Result();
1199 ShapeFix::SameParameter ( ResultShape, Standard_False );
1203 **Note** that the use of method *ShapeFix::SameParameter* is necessary, otherwise the parameter edges obtained as a result of splitting can be different.
1205 #### Additional methods
1207 * Class *ShapeUpgrade_FaceDivideArea* inherited from *ShapeUpgrade_FaceDivide* is intended for splitting a face by the maximal area criterion.
1208 * Class *ShapeUpgrade_SplitSurfaceArea* inherited from *ShapeUpgrade_SplitSurface* calculates the parameters of face splitting in the parametric space.
1211 @subsection occt_shg_4_4 Customization of shapes
1213 Customization tools are intended for adaptation of shape geometry in compliance with the customer needs. They modify a geometrical object to another one in the shape.
1215 To implement the necessary shape modification it is enough to initialize the appropriate tool by the shape and desirable parameters and to get the resulting shape. For example for conversion of indirect surfaces in the shape do the following:
1218 TopoDS_Shape initialShape ..
1219 TopoDS_Shape resultShape = ShapeCustom::DirectFaces(initialShape);
1222 @subsubsection occt_shg_4_4_1 Conversion of indirect surfaces.
1225 ShapeCustom::DirectFaces
1226 static TopoDS_Shape DirectFaces(const TopoDS_Shape& S);
1229 This method provides conversion of indirect elementary surfaces (elementary surfaces with left-handed coordinate systems) in the shape into direct ones. New 2d curves (recomputed for converted surfaces) are added to the same edges being shared by both the resulting shape and the original shape *S*.
1231 @subsubsection occt_shg_4_4_2 Shape Scaling
1234 ShapeCustom::ScaleShape
1235 TopoDS_Shape ShapeCustom::ScaleShape(const TopoDS_Shape& S,
1236 const Standard_Real scale);
1239 This method returns a new shape, which is a scaled original shape with a coefficient equal to the specified value of scale. It uses the tool *ShapeCustom_TrsfModification*.
1241 @subsubsection occt_shg_4_4_3 Conversion of curves and surfaces to BSpline
1243 *ShapeCustom_BSplineRestriction* allows approximation of surfaces, curves and 2D curves with a specified degree, maximum number of segments, 2d tolerance and 3d tolerance. If the approximation result cannot be achieved with the specified continuity, the latter can be reduced.
1245 The method with all parameters looks as follows:
1247 ShapeCustom::BsplineRestriction
1248 TopoDS_Shape ShapeCustom::BSplineRestriction (const TopoDS_Shape& S,
1249 const Standard_Real Tol3d, const Standard_Real Tol2d,
1250 const Standard_Integer MaxDegree,
1251 const Standard_Integer MaxNbSegment,
1252 const GeomAbs_Shape Continuity3d,
1253 const GeomAbs_Shape Continuity2d,
1254 const Standard_Boolean Degree,
1255 const Standard_Boolean Rational,
1256 const Handle(ShapeCustom_RestrictionParameters)& aParameters)
1259 It returns a new shape with all surfaces, curves and 2D curves of BSpline/Bezier type or based on them, converted with a degree less than *MaxDegree* or with a number of spans less then *NbMaxSegment* depending on the priority parameter *Degree*. If this parameter is equal to True then *Degree* will be increased to the value *GmaxDegree*, otherwise *NbMaxSegments* will be increased to the value *GmaxSegments*. *GmaxDegree* and *GMaxSegments* are the maximum possible degree and the number of spans correspondingly. These values will be used in cases when an approximation with specified parameters is impossible and either *GmaxDegree* or *GMaxSegments* is selected depending on the priority.
1261 Note that if approximation is impossible with *GMaxDegree*, even then the number of spans can exceed the specified *GMaxSegment*. *Rational* specifies whether Rational BSpline/Bezier should be converted into polynomial B-Spline.
1263 Also note that the continuity of surfaces in the resulting shape can be less than the given value.
1267 To convert other types of curves and surfaces to BSpline with required parameters it is necessary to use flags from class ShapeCustom_RestrictionParameters, which is just a container of flags.
1268 The following flags define whether a specified-type geometry has been converted to BSpline with the required parameters:
1270 * *ConvertBezierSurf,*
1271 * *ConvertRevolutionSurf,*
1272 * *ConvertExtrusionSurf,*
1273 * *ConvertOffsetSurf,*
1274 * *ConvertCurve3d,* -- for conversion of all types of 3D curves.
1275 * *ConvertOffsetCurv3d,* -- for conversion of offset 3D curves.
1276 * *ConvertCurve2d,* -- for conversion of all types of 2D curves.
1277 * *ConvertOffsetCurv2d,* -- for conversion of offset 2D curves.
1278 * *SegmentSurfaceMode* -- defines whether the surface would be approximated within the boundaries of the face lying on this surface.
1282 @subsubsection occt_shg_4_4_4 Conversion of elementary surfaces into surfaces of revolution
1285 ShapeCustom::ConvertToRevolution()
1286 TopoDS_Shape ShapeCustom::ConvertToRevolution(const TopoDS_Shape& S) ;
1289 This method returns a new shape with all elementary periodic surfaces converted to *Geom_SurfaceOfRevolution*. It uses the tool *ShapeCustom_ConvertToRevolution*.
1291 @subsubsection occt_shg_4_4_5 Conversion of elementary surfaces into Bspline surfaces
1294 ShapeCustom::ConvertToBSpline()
1295 TopoDS_Shape ShapeCustom::ConvertToBSpline( const TopoDS_Shape& S,
1296 const Standard_Boolean extrMode,
1297 const Standard_Boolean revolMode,
1298 const Standard_Boolean offsetMode);
1301 This method returns a new shape with all surfaces of linear extrusion, revolution and offset surfaces converted according to flags to *Geom_BSplineSurface* (with the same parameterization). It uses the tool *ShapeCustom_ConvertToBSpline*.
1303 @subsubsection occt_shg_4_4_6 Getting the history of modification of sub-shapes.
1304 If, in addition to the resulting shape, you want to get the history of modification of sub-shapes you should not use the package methods described above and should use your own code instead:
1305 1. Create a tool that is responsible for the necessary modification.
1306 2. Create the tool *BRepTools_Modifier* that performs a specified modification in the shape.
1307 3. To get the history and to keep the assembly structure use the method *ShapeCustom::ApplyModifier*.
1310 The general calling syntax for scaling is
1312 TopoDS_Shape scaled_shape = ShapeCustom::ScaleShape(shape, scale);
1315 Note that scale is a real value. You can refine your mapping process by using additional calls to follow shape mapping sub-shape by sub-shape. The following code along with pertinent includes can be used:
1319 Standard_Real scale = 100; // for example!
1320 T.SetScale (gp_Pnt (0, 0, 0), scale);
1321 Handle(ShapeCustom_TrsfModification) TM = new
1322 ShapeCustom_TrsfModification(T);
1323 TopTools_DataMapOfShapeShape context;
1324 BRepTools_Modifier MD;
1325 TopoDS_Shape res = ShapeCustom::ApplyModifier (
1326 Shape, TM, context,MD );
1329 The map, called context in our example, contains the history.
1330 Substitutions are made one by one and all shapes are transformed.
1331 To determine what happens to a particular sub-shape, it is possible to use:
1334 TopoDS_Shape oneres = context.Find (oneshape);
1335 //In case there is a doubt, you can also add:
1336 if (context.IsBound(oneshape)) oneres = context.Find(oneshape);
1337 //You can also sweep the entire data map by using:
1338 TopTools_DataMapIteratorOfDataMapOfShapeShape
1339 //To do this, enter:
1340 for(TopTools_DataMapIteratorOfDataMapOfShapeShape
1341 iter(context);iter(more ();iter.next ()) {
1342 TopoDs_Shape oneshape = iter.key ();
1343 TopoDs_Shape oneres = iter.value ();
1348 @subsubsection occt_shg_4_4_7 Remove internal wires
1350 *ShapeUpgrade_RemoveInternalWires* tool removes internal wires with contour area less than the specified minimal area. It can work with compounds, solids, shells and faces.
1352 If the flag *RemoveFaceMode* is set to TRUE, separate faces or a group of faces with outer wires, which consist only of edges that belong to the removed internal wires, are removed (seam edges are not taken into account). Such faces can be removed only for a sewed shape.
1354 Internal wires can be removed by the methods *Perform*. Both methods *Perform* can not be carried out if the class has not been initialized by the shape. In such case the status of *Perform* is set to FAIL .
1356 The method *Perform* without arguments removes from all faces in the specified shape internal wires whose area is less than the minimal area.
1358 The other method *Perform* has a sequence of shapes as an argument. This sequence can contain faces or wires.
1359 If the sequence of shapes contains wires, only the internal wires are removed.
1361 If the sequence of shapes contains faces, only the internal wires from these faces are removed.
1363 * The status of the performed operation can be obtained using method *Status()*;
1364 * The resulting shape can be obtained using method *GetResult()*.
1366 An example of using this tool is presented in the figures below:
1368 @figure{/user_guides/shape_healing/images/shape_healing_image005.png,"Source Face",240}
1369 @figure{/user_guides/shape_healing/images/shape_healing_image006.png,"Resulting shape",240}
1371 After the processing three internal wires with contour area less than the specified minimal area have been removed. One internal face has been removed. The outer wire of this face consists of the edges belonging to the removed internal wires and a seam edge.
1372 Two other internal faces have not been removed because their outer wires consist not only of edges belonging to the removed wires.
1374 @figure{/user_guides/shape_healing/images/shape_healing_image007.png,"Source Face",240}
1376 @figure{/user_guides/shape_healing/images/shape_healing_image008.png,"Resulting shape",240}
1378 After the processing six internal wires with contour area less than the specified minimal area have been removed. Six internal faces have been removed. These faces can be united into groups of faces. Each group of faces has an outer wire consisting only of edges belonging to the removed internal wires. Such groups of faces are also removed.
1380 The example of method application is also given below:
1383 //Initialization of the class by shape.
1384 Handle(ShapeUpgrade_RemoveInternalWires) aTool = new ShapeUpgrade_RemoveInternalWires(inputShape);
1385 //setting parameters
1386 aTool->MinArea() = aMinArea;
1387 aTool->RemoveFaceMode() = aModeRemoveFaces;
1389 //when method Perform is carried out on separate shapes.
1390 aTool->Perform(aSeqShapes);
1392 //when method Perform is carried out on whole shape.
1394 //check status set after method Perform
1395 if(aTool->Status(ShapeExtend_FAIL) {
1396 cout<<"Operation failed"<< <<"\n";
1400 if(aTool->Status(ShapeExtend_DONE1)) {
1401 const TopTools_SequenceOfShape& aRemovedWires =aTool->RemovedWires();
1402 cout<<aRemovedWires.Length()<<" internal wires were removed"<<"\n";
1406 if(aTool->Status(ShapeExtend_DONE2)) {
1407 const TopTools_SequenceOfShape& aRemovedFaces =aTool->RemovedFaces();
1408 cout<<aRemovedFaces.Length()<<" small faces were removed"<<"\n";
1411 //getting result shape
1412 TopoDS_Shape res = aTool->GetResult();
1415 @subsubsection occt_shg_4_4_8 Conversion of surfaces
1417 Class ShapeCustom_Surface allows:
1418 * converting BSpline and Bezier surfaces to the analytical form (using method *ConvertToAnalytical())*
1419 * converting closed B-Spline surfaces to periodic ones.(using method *ConvertToPeriodic*)
1421 To convert surfaces to analytical form this class analyzes the form and the closure of the source surface and defines whether it can be approximated by analytical surface of one of the following types:
1423 * *Geom_SphericalSurface,*
1424 * *Geom_CylindricalSurface,*
1425 * *Geom_ConicalSurface,*
1426 * *Geom_ToroidalSurface*.
1428 The conversion is done only if the new (analytical) surface does not deviate from the source one more than by the given precision.
1431 Handle(Geom_Surface) initSurf;
1432 ShapeCustom_Surface ConvSurf(initSurf);
1433 //conversion to analytical form
1434 Handle(Geom_Surface) newSurf = ConvSurf.ConvertToAnalytical(allowedtol,Standard_False);
1435 //or conversion to a periodic surface
1436 Handle(Geom_Surface) newSurf = ConvSurf.ConvertToPeriodic(Standard_False);
1437 //getting the maximum deviation of the new surface from the initial surface
1438 Standard_Real maxdist = ConvSurf.Gap();
1441 @subsubsection occt_shg_4_4_9 Unify Same Domain
1443 *ShapeUpgrade_UnifySameDomain* tool allows unifying all possible faces and edges of a shape, which lies on the same geometry. Faces/edges are considered as 'same-domain' if the neighboring faces/edges lie on coincident surfaces/curves. Such faces/edges can be unified into one face/edge.
1444 This tool takes an input shape and returns a new one. All modifications of the initial shape are recorded during the operation.
1446 The following options are available:
1448 * If the flag *UnifyFaces* is set to TRUE, *UnifySameDomain* tries to unify all possible faces;
1449 * If the flag *UnifyEdges* is set to TRUE, *UnifySameDomain* tries to unify all possible edges;
1450 * if the flag *ConcatBSplines* is set to TRUE, all neighboring edges, which lie on the BSpline or Bezier curves with C1 continuity on their common vertices will be merged into one common edge.
1452 By default, *UnifyFaces* and *UnifyEdges* are set to TRUE; *ConcatBSplines* is set to FALSE.
1454 The common methods of this tool are as follows:
1456 * Method *Build()* is used to unify.
1457 * Method *Shape()* is used to get the resulting shape.
1458 * Method *Generated()* is used to get a new common shape from the old shape. If a group of edges has been unified into one common edge then method *Generated()* called on any edge from this group will return the common edge. The same goes for the faces.
1460 The example of the usage is given below:
1462 // 'Sh' is the initial shape
1463 ShapeUpgrade_UnifySameDomain USD(Sh, true, true, true); // UnifyFaces mode on, UnifyEdges mode on, ConcatBSplines mode on.
1466 TopoDS_Shape Result = USD.Shape();
1467 //Let Sh1 as a part of Sh
1468 //get the new (probably unified) shape form the Sh1
1469 TopoDS_Shape ResSh1 = USD.Generated(Sh1);
1472 @section occt_shg_5_ Auxiliary tools for repairing, analysis and upgrading
1474 @subsection occt_shg_5_1 Tool for rebuilding shapes
1476 Class *ShapeBuild_ReShape* rebuilds a shape by making predefined substitutions on some of its components. During the first phase, it records requests to replace or remove some individual shapes. For each shape, the last given request is recorded. Requests may be applied as *Oriented* (i.e. only to an item with the same orientation) or not (the orientation of the replacing shape corresponds to that of the original one). Then these requests may be applied to any shape, which may contain one or more of these individual shapes.
1478 This tool has a flag for taking the location of shapes into account (for keeping the structure of assemblies) (*ModeConsiderLocation*). If this mode is equal to Standard_True, the shared shapes with locations will be kept. If this mode is equal to Standard_False, some different shapes will be produced from one shape with different locations after rebuilding. By default, this mode is equal to Standard_False.
1480 To use this tool for the reconstruction of shapes it is necessary to take the following steps:
1481 1. Create this tool and use method *Apply()* for its initialization by the initial shape. Parameter *until* sets the level of shape type and requests are taken into account up to this level only. Sub-shapes of the type standing beyond the *line* set by parameter until will not be rebuilt and no further exploration will be done
1482 2. Replace or remove sub-shapes of the initial shape. Each sub-shape can be replaced by a shape of the same type or by shape containing shapes of that type only (for example, *TopoDS_Edge* can be replaced by *TopoDS_Edge, TopoDS_Wire* or *TopoDS_Compound* containing *TopoDS_Edges*). If an incompatible shape type is encountered, it is ignored and flag FAIL1 is set in Status.
1483 For a sub-shape it is recommended to use method *Apply* before methods *Replace* and *Remove*, because the sub-shape has already been changed for the moment by its previous modifications or modification of its sub-shape (for example *TopoDS_Edge* can be changed by a modification of its *TopoDS_Vertex*, etc.).
1484 3. Use method *Apply* for the initial shape again to get the resulting shape after all modifications have been made.
1485 4. Use method *Apply* to obtain the history of sub-shape modification.
1487 Additional method *IsNewShape* can be used to check if the shape has been recorded by *BRepTools_ReShape* tool as a value.
1489 **Note** that in fact class *ShapeBuild_ReShape* is an alias for class *BRepTools_ReShape*. They differ only in queries of statuses in the *ShapeBuild_ReShape* class.
1491 Let us use the tool to get the result shape after modification of sub-shapes of the initial shape:
1494 TopoDS_Shape initialShape…
1495 //creation of a rebuilding tool
1496 Handle(ShapeBuild_ReShape) Context = new ShapeBuild_ReShape.
1498 //next step is optional. It can be used for keeping the assembly structure.
1499 Context-> ModeConsiderLocation = Standard_True;
1501 //initialization of this tool by the initial shape
1502 Context->Apply(initialShape);
1504 //getting the intermediate result for replacing subshape1 with the modified subshape1.
1505 TopoDS_Shape tempshape1 = Context->Apply(subshape1);
1507 //replacing the intermediate shape obtained from subshape1 with the newsubshape1.
1508 Context->Replace(tempsubshape1,newsubshape1);
1510 //for removing the sub-shape
1511 TopoDS_Shape tempshape2 = Context->Apply(subshape2);
1512 Context->Remove(tempsubshape2);
1514 //getting the result and the history of modification
1515 TopoDS_Shape resultShape = Context->Apply(initialShape);
1517 //getting the resulting sub-shape from the subshape1 of the initial shape.
1518 TopoDS_Shape result_subshape1 = Context->Apply(subshape1);
1521 @subsection occt_shg_5_2 Status definition
1523 *ShapExtend_Status* is used to report the status after executing some methods that can either fail, do something, or do nothing. The status is a set of flags *DONEi* and *FAILi*. Any combination of them can be set at the same time. For exploring the status, enumeration is used.
1525 The values have the following meaning:
1528 | :----- | :----------------- |
1529 | *OK,* | Nothing is done, everything OK |
1530 | *DONE1,* | Something was done, case 1 |
1531 | *DONE8*, | Something was done, case 8 |
1532 | *DONE*, | Something was done (any of DONE#) |
1533 | *FAIL1*, | The method failed, case 1 |
1534 | *FAIL8*, | The method failed, case 8 |
1535 | *FAIL* | The method failed (any of FAIL# occurred) |
1538 @subsection occt_shg_5_3 Tool representing a wire
1539 Class *ShapeExtend_WireData* provides a data structure necessary to work with the wire as with an ordered list of edges, and that is required for many algorithms. The advantage of this class is that it allows to work with incorrect wires.
1541 The object of the class *ShapeExtend_WireData* can be initialized by *TopoDS_Wire* and converted back to *TopoDS_Wire*.
1543 An edge in the wire is defined by its rank number. Operations of accessing, adding and removing an edge at/to the given rank number are provided. Operations of circular permutation and reversing (both orientations of all edges and the order of edges) are provided on the whole wire as well.
1545 This class also provides a method to check if the edge in the wire is a seam (if the wire lies on a face).
1547 Let us remove edges from the wire and define whether it is seam edge
1550 TopoDS_Wire ini = ..
1551 Handle(ShapeExtend_Wire) asewd = new ShapeExtend_Wire(initwire);
1552 //Removing edge Edge1 from the wire.
1554 Standard_Integer index_edge1 = asewd->Index(Edge1);
1555 asewd.Remove(index_edge1);
1556 //Definition of whether Edge2 is a seam edge
1557 Standard_Integer index_edge2 = asewd->Index(Edge2);
1558 asewd->IsSeam(index_edge2);
1562 @subsection occt_shg_5_4 Tool for exploring shapes
1563 Class *ShapeExtend_Explorer* is intended to explore shapes and convert different representations (list, sequence, compound) of complex shapes. It provides tools for:
1564 * obtaining the type of the shapes in the context of *TopoDS_Compound*,
1565 * exploring shapes in the context of *TopoDS_Compound*,
1566 * converting different representations of shapes (list, sequence, compound).
1568 @subsection occt_shg_5_5 Tool for attaching messages to objects
1569 Class *ShapeExtend_MsgRegistrator* attaches messages to objects (generic Transient or shape). The objects of this class are transmitted to the Shape Healing algorithms so that they could collect messages occurred during shape processing. Messages are added to the Maps (stored as a field) that can be used, for instance, by Data Exchange processors to attach those messages to initial file entities.
1571 Let us send and get a message attached to object:
1574 Handle(ShapeExtend_MsgRegistrator) MessageReg = new ShapeExtend_MsgRegistrator;
1575 //attaches messages to an object (shape or entity)
1577 TopoDS_Shape Shape1…
1578 MessageReg->Send(Shape1,msg,Message_WARNING);
1579 Handle(Standard_Transient) ent ..
1580 MessageReg->Send(ent,msg,Message_WARNING);
1581 //gets messages attached to shape
1582 const ShapeExtend_DataMapOfShapeListOfMsg& msgmap = MessageReg->MapShape();
1583 if (msgmap.IsBound (Shape1)) {
1584 const Message_ListOfMsg &msglist = msgmap.Find (Shape1);
1585 for (Message_ListIteratorOfListOfMsg iter (msglist);
1586 iter.More(); iter.Next()) {
1587 Message_Msg msg = iter.Value();
1592 @subsection occt_shg_5_6 Tools for performance measurement
1594 Classes *MoniTool_Timer* and *MoniTool_TimerSentry* are used for measuring the performance of a current operation or any part of code, and provide the necessary API. Timers are used for debugging and performance optimizing purposes.
1596 Let us try to use timers in *XSDRAWIGES.cxx* and *IGESBRep_Reader.cxx* to analyse the performance of command *igesbrep*:
1601 #include <MoniTool_Timer.hxx>
1602 #include <MoniTool_TimerSentry.hxx>
1604 MoniTool_Timer::ClearTimers();
1606 MoniTool_TimerSentry MTS("IGES_LoadFile");
1607 Standard_Integer status = Reader.LoadFile(fnom.ToCString());
1610 MoniTool_Timer::DumpTimers(cout);
1616 #include <MoniTool_TimerSentry.hxx>
1618 Standard_Integer nb = theModel->NbEntities();
1620 for (Standard_Integer i=1; i<=nb; i++) {
1621 MoniTool_TimerSentry MTS("IGESToBRep_Transfer");
1625 shape = TransferBRep::ShapeResult (theProc,ent);
1631 The result of *DumpTimer()* after file translation is as follows:
1633 | TIMER | Elapsed | CPU User | CPU Sys | Hits |
1634 | :--- | :---- | :----- | :---- | :---- |
1635 | *IGES_LoadFile* | 1.0 sec | 0.9 sec | 0.0 sec | 1 |
1636 | *IGESToBRep_Transfer* | 14.5 sec | 4.4 sec | 0.1 sec | 1311 |
1639 @section occt_shg_6 Shape Processing
1641 @subsection occt_shg_6_1 Usage Workflow
1643 The Shape Processing module allows defining and applying the general Shape Processing as a customizable sequence of Shape Healing operators. The customization is implemented via the user-editable resource file, which defines the sequence of operators to be executed and their parameters.
1645 The Shape Processing functionality is implemented with the help of the *XSAlgo* interface. The main function *XSAlgo_AlgoContainer::ProcessShape()* does shape processing with specified tolerances and returns the resulting shape and associated information in the form of *Transient*.
1647 This function is used in the following way:
1650 TopoDS_Shape aShape = …;
1651 Standard_Real Prec = …,
1652 Standard_Real MaxTol = …;
1653 TopoDS_Shape aResult;
1654 Handle(Standard_Transient) info;
1655 TopoDS_Shape aResult = XSAlgo::AlgoContainer()->ProcessShape(aShape, Prec, MaxTol., "Name of ResourceFile", "NameSequence", info );
1658 Let us create a custom sequence of operations:
1660 1. Create a resource file with the name *ResourceFile*, which includes the following string:
1662 NameSequence.exec.op: MyOper
1664 where *MyOper* is the name of operation.
1665 2. Input a custom parameter for this operation in the resource file, for example:
1667 NameSequence.MyOper.Tolerance: 0.01
1669 where *Tolerance* is the name of the parameter and 0.01 is its value.
1670 3. Add the following string into *void ShapeProcess_OperLibrary::Init()*:
1672 ShapeProcess::RegisterOperator(;MyOper;,
1673 new ShapeProcess_UOperator(myfunction));
1675 where *myfunction* is a function which implements the operation.
1676 4. Create this function in *ShapeProcess_OperLibrary* as follows:
1678 static Standard_Boolean myfunction (const
1679 Handle(ShapeProcess_Context)& context)
1681 Handle(ShapeProcess_ShapeContext) ctx = Handle(ShapeProcess_ShapeContext)::DownCast(context);
1682 if(ctx.IsNull()) return Standard_False;
1683 TopoDS_Shape aShape = ctx->Result();
1684 //receive our parameter:
1685 Standard_Real toler;
1686 ctx->GetReal(;Tolerance;, toler);
1688 5. Make the necessary operations with *aShape* using the received value of parameter *Tolerance* from the resource file.
1690 return Standard_True;
1693 6. Define some operations (with their parameters) *MyOper1, MyOper2, MyOper3*, etc. and describe the corresponding functions in *ShapeProcess_OperLibrary*.
1694 7. Perform the required sequence using the specified name of operations and values of parameters in the resource file.
1696 For example: input of the following string:
1698 NameSequence.exec.op: MyOper1,MyOper3
1700 means that the corresponding functions from *ShapeProcess_OperLibrary* will be performed with the original shape *aShape* using parameters defined for *MyOper1* and *MyOper3* in the resource file.
1702 It is necessary to note that these operations will be performed step by step and the result obtained after performing the first operation will be used as the initial shape for the second operation.
1704 @subsection occt_shg_6_2 Operators
1707 This operator sets all faces based on indirect surfaces, defined with left-handed coordinate systems as direct faces. This concerns surfaces defined by Axis Placement (Cylinders, etc). Such Axis Placement may be indirect, which is allowed in Cascade, but not allowed in some other systems. This operator reverses indirect placements and recomputes PCurves accordingly.
1710 This operator is required after calling some other operators, according to the computations they do. Its call is explicit, so each call can be removed according to the operators, which are either called or not afterwards. This mainly concerns splitting operators that can split edges.
1712 The operator applies the computation *SameParameter* which ensures that various representations of each edge (its 3d curve, the pcurve on each of the faces on which it lies) give the same 3D point for the same parameter, within a given tolerance.
1713 * For each edge coded as *same parameter*, deviation of curve representation is computed and if the edge tolerance is less than that deviation, the tolerance is increased so that it satisfies the deviation. No geometry modification, only an increase of tolerance is possible.
1714 * For each edge coded as *not same parameter* the deviation is computed as in the first case. Then an attempt is made to achieve the edge equality to *same parameter* by means of modification of 2d curves. If the deviation of this modified edge is less than the original deviation then this edge is returned, otherwise the original edge (with non-modified 2d curves) is returned with an increased (if necessary) tolerance. Computation is done by call to the standard algorithm *BRepLib::SameParameter*.
1716 This operator can be called with the following parameters:
1717 * *Boolean : Force* (optional) -- if True, encodes all edges as *not same parameter* then runs the computation. Else, the computation is done only for those edges already coded as *not same parameter*.
1718 * *Real : Tolerance3d* (optional) -- if not defined, the local tolerance of each edge is taken for its own computation. Else, this parameter gives the global tolerance for the whole shape.
1720 ### BSplineRestriction
1722 This operator is used for conversion of surfaces, curves 2d curves to BSpline surfaces with a specified degree and a specified number of spans. It performs approximations on surfaces, curves and 2d curves with a specified degree, maximum number of segments, 2d tolerance, 3d tolerance. The specified continuity can be reduced if the approximation with a specified continuity was not done successfully.
1724 This operator can be called with the following parameters:
1725 * *Boolean : SurfaceMode* allows considering the surfaces;
1726 * *Boolean : Curve3dMode* allows considering the 3d curves;
1727 * *Boolean : Curve2dMode* allows considering the 2d curves;
1728 * *Real : Tolerance3d* defines 3d tolerance to be used in computation;
1729 * *Real : Tolerance2d* defines 2d tolerance to be used when computing 2d curves;
1730 * *GeomAbs_Shape (C0 G1 C1 G2 C2 CN) : Continuity3d* is the continuity required in 2d;
1731 * *GeomAbs_Shape (C0 G1 C1 G2 C2 CN) : Continuity2d* is the continuity required in 3d;
1732 * *Integer : RequiredDegree* gives the required degree;
1733 * *Integer : RequiredNbSegments* gives the required number of segments;
1734 * *Boolean : PreferDegree* if true, *RequiredDegree* has a priority, else *RequiredNbSegments* has a priority;
1735 * *Boolean : RationalToPolynomial* serves for conversion of BSplines to polynomial form;
1736 * *Integer : MaxDegree* gives the maximum allowed Degree, if *RequiredDegree* cannot be reached;
1737 * *Integer : MaxNbSegments* gives the maximum allowed NbSegments, if *RequiredNbSegments* cannot be reached.
1739 The following flags allow managing the conversion of special types of curves or surfaces, in addition to BSpline. They are controlled by *SurfaceMode, Curve3dMode* or *Curve2dMode* respectively; by default, only BSplines and Bezier Geometries are considered:
1740 * *Boolean : OffsetSurfaceMode*
1741 * *Boolean : LinearExtrusionMode*
1742 * *Boolean : RevolutionMode*
1743 * *Boolean : OffsetCurve3dMode*
1744 * *Boolean : OffsetCurve2dMode*
1745 * *Boolean : PlaneMode*
1746 * *Boolean : BezierMode*
1747 * *Boolean : ConvCurve3dMode*
1748 * *Boolean : ConvCurve2dMode*
1750 For each of the Mode parameters listed above, if it is True, the specified geometry is converted to BSpline, otherwise only its basic geometry is checked and converted (if necessary) keeping the original type of geometry (revolution, offset, etc).
1752 * *Boolean :SegmentSurfaceMode* has effect only for Bsplines and Bezier surfaces. When False a surface will be replaced by a Trimmed Surface, else new geometry will be created by splitting the original Bspline or Bezier surface.
1754 ### ElementaryToRevolution
1756 This operator converts elementary periodic surfaces to SurfaceOfRevolution.
1760 This operator splits surfaces of revolution, cylindrical, toroidal, conical, spherical surfaces in the given shape so that each resulting segment covers not more than the defined number of degrees.
1762 It can be called with the following parameters:
1763 * *Real : Angle* -- the maximum allowed angle for resulting faces;
1764 * *Real : MaxTolerance* -- the maximum tolerance used in computations.
1766 ### SurfaceToBSpline
1767 This operator converts some specific types of Surfaces, to BSpline (according to parameters).
1768 It can be called with the following parameters:
1769 * *Boolean : LinearExtrusionMode* allows converting surfaces of Linear Extrusion;
1770 * *Boolean : RevolutionMode* allows converting surfaces of Revolution;
1771 * *Boolean : OffsetMode* allows converting Offset Surfaces
1775 This operator is used for data supported as Bezier only and converts various types of geometries to Bezier. It can be called with the following parameters used in computation of conversion :
1776 * *Boolean : SurfaceMode*
1777 * *Boolean : Curve3dMode*
1778 * *Boolean : Curve2dMode*
1779 * *Real : MaxTolerance*
1780 * *Boolean : SegmentSurfaceMode* (default is True) has effect only for Bsplines and Bezier surfaces. When False a surface will be replaced by a Trimmed Surface, else new geometry will be created by splitting the original Bspline or Bezier surface.
1782 The following parameters are controlled by *SurfaceMode, Curve3dMode* or *Curve2dMode* (according to the case):
1783 * *Boolean : Line3dMode*
1784 * *Boolean : Circle3dMode*
1785 * *Boolean : Conic3dMode*
1786 * *Boolean : PlaneMode*
1787 * *Boolean : RevolutionMode*
1788 * *Boolean : ExtrusionMode*
1789 * *Boolean : BSplineMode*
1792 This operator splits a shape in order to have each geometry (surface, curve 3d, curve 2d) correspond the given criterion of continuity. It can be called with the following parameters:
1793 * *Real : Tolerance3d*
1794 * *Integer (GeomAbs_Shape ) : CurveContinuity*
1795 * *Integer (GeomAbs_Shape ) : SurfaceContinuity*
1796 * *Real : MaxTolerance*
1798 Because of algorithmic limitations in the operator *BSplineRestriction* (in some particular cases, this operator can produce unexpected C0 geometry), if *SplitContinuity* is called, it is recommended to call it after *BSplineRestriction*.
1799 Continuity Values will be set as *GeomAbs_Shape* (i.e. C0 G1 C1 G2 C2 CN) besides direct integer values (resp. 0 1 2 3 4 5).
1801 ### SplitClosedFaces
1802 This operator splits faces, which are closed even if they are not revolutionary or cylindrical, conical, spherical, toroidal. This corresponds to BSpline or Bezier surfaces which can be closed (whether periodic or not), hence they have a seam edge. As a result, no more seam edges remain. The number of points allows to control the minimum count of faces to be produced per input closed face.
1804 This operator can be called with the following parameters:
1805 * *Integer : NbSplitPoints* gives the number of points to use for splitting (the number of intervals produced is *NbSplitPoints+1*);
1806 * *Real : CloseTolerance* tolerance used to determine if a face is closed;
1807 * *Real : MaxTolerance* is used in the computation of splitting.
1811 This operator must be called when *FixFaceSize* and/or *DropSmallEdges* are called. Using Surface Healing may require an additional call to *BSplineRestriction* to ensure that modified geometries meet the requirements for BSpline.
1812 This operators repairs geometries which contain gaps between edges in wires (always performed) or gaps on faces, controlled by parameter *SurfaceMode*, Gaps on Faces are fixed by using algorithms of Surface Healing
1813 This operator can be called with the following parameters:
1814 * *Real : Tolerance3d* sets the tolerance to reach in 3d. If a gap is less than this value, it is not fixed.
1815 * *Boolean : SurfaceMode* sets the mode of fixing gaps between edges and faces (yes/no) ;
1816 * *Integer : SurfaceAddSpans* sets the number of spans to add to the surface in order to fix gaps ;
1817 * *GeomAbs_Shape (C0 G1 C1 G2 C2 CN) : SurfaceContinuity* sets the minimal continuity of a resulting surface ;
1818 * *Integer : NbIterations* sets the number of iterations
1819 * *Real : Beta* sets the elasticity coefficient for modifying a surface [1-1000] ;
1820 * *Reals : Coeff1 to Coeff6* sets energy coefficients for modifying a surface [0-10000] ;
1821 * *Real : MaxDeflection* sets maximal deflection of surface from an old position.
1823 This operator may change the original geometry. In addition, it is CPU consuming, and it may fail in some cases. Also **FixGaps** can help only when there are gaps obtained as a result of removal of small edges that can be removed by **DropSmallEdges** or **FixFaceSize**.
1826 This operator removes faces, which are small in all directions (spot face) or small in one direction (strip face). It can be called with the parameter *Real : Tolerance*, which sets the minimal dimension, which is used to consider a face, is small enough to be removed.
1829 This operator drops edges in a wire, and merges them with adjacent edges, when they are smaller than the given value (*Tolerance3d*) and when the topology allows such merging (i.e. same adjacent faces for each of the merged edges). Free (non-shared by adjacent faces) small edges can be also removed in case if they share the same vertex Parameters.
1831 It can be called with the parameter *Real : Tolerance3d*, which sets the dimension used to determine if an edge is small.
1835 This operator may be added for fixing invalid shapes. It performs various checks and fixes, according to the modes listed hereafter. Management of a set of fixes can be performed by flags as follows:
1836 * if the flag for a fixing tool is set to 0 , it is not performed;
1837 * if set to 1 , it is performed in any case;
1838 * if not set, or set to -1 , for each shape to be applied on, a check is done to evaluate whether a fix is needed. The fix is performed if the check is positive.
1840 By default, the flags are not set, the checks are carried out each individual shape.
1842 This operator can be called with the following parameters:
1843 * *Real : Tolerance3d* sets basic tolerance used for fixing;
1844 * *Real : MaxTolerance3d* sets maximum allowed value for the resulting tolerance;
1845 * *Real : MinTolerance3d* sets minimum allowed value for the resulting tolerance.
1846 * *Boolean : FixFreeShellMode*
1847 * *Boolean : FixFreeFaceMode*
1848 * *Boolean : FixFreeWireMode*
1849 * *Boolean : FixSameParameterMode*
1850 * *Boolean : FixSolidMode*
1851 * *Boolean : FixShellMode*
1852 * *Boolean : FixFaceMode*
1853 * *Boolean : FixWireMode*
1854 * *Boolean : FixOrientationMode*
1855 * *Boolean : FixMissingSeamMode*
1856 * *Boolean : FixSmallAreaWireMode*
1857 * *Boolean (not checked) : ModifyTopologyMode* specifies the mode for modifying topology. Should be False (default) for shapes with shells and can be True for free faces.
1858 * *Boolean (not checked) : ModifyGeometryMode* specifies the mode for modifying geometry. Should be False if geometry is to be kept and True if it can be modified.
1859 * *Boolean (not checked) : ClosedWireMode* specifies the mode for wires. Should be True for wires on faces and False for free wires.
1860 * *Boolean (not checked) : PreferencePCurveMode (not used)* specifies the preference of 3d or 2d representations for an edge
1861 * *Boolean : FixReorderMode*
1862 * *Boolean : FixSmallMode*
1863 * *Boolean : FixConnectedMode*
1864 * *Boolean : FixEdgeCurvesMode*
1865 * *Boolean : FixDegeneratedMode*
1866 * *Boolean : FixLackingMode*
1867 * *Boolean : FixSelfIntersectionMode*
1868 * *Boolean : FixGaps3dMode*
1869 * *Boolean : FixGaps2dMode*
1870 * *Boolean : FixReversed2dMode*
1871 * *Boolean : FixRemovePCurveMode*
1872 * *Boolean : FixRemoveCurve3dMode*
1873 * *Boolean : FixAddPCurveMode*
1874 * *Boolean : FixAddCurve3dMode*
1875 * *Boolean : FixSeamMode*
1876 * *Boolean : FixShiftedMode*
1877 * *Boolean : FixEdgeSameParameterMode*
1878 * *Boolean : FixSelfIntersectingEdgeMode*
1879 * *Boolean : FixIntersectingEdgesMode*
1880 * *Boolean : FixNonAdjacentIntersectingEdgesMode*
1882 ### SplitClosedEdges
1883 This operator handles closed edges i.e. edges with one vertex. Such edges are not supported in some receiving systems. This operator splits topologically closed edges (i.e. edges having one vertex) into two edges. Degenerated edges and edges with a size of less than Tolerance are not processed.
1885 @section occt_shg_7 Messaging mechanism
1887 Various messages about modification, warnings and fails can be generated in the process of shape fixing or upgrade. The messaging mechanism allows generating messages, which will be sent to the chosen target medium a file or the screen. The messages may report failures and/or warnings or provide information on events such as analysis, fixing or upgrade of shapes.
1889 @subsection occt_shg_7_1 Message Gravity
1890 Enumeration *Message_Gravity* is used for defining message gravity.
1891 It provides the following message statuses:
1892 * *Message_FAIL* -- the message reports a fail;
1893 * *Message_WARNING* -- the message reports a warning;
1894 * *Message_INFO* -- the message supplies information.
1896 @subsection occt_shg_7_2 Tool for loading a message file into memory
1897 Class *Message_MsgFile* allows defining messages by loading a custom message file into memory. It is necessary to create a custom message file before loading it into memory, as its path will be used as the argument to load it. Each message in the message file is identified by a key. The user can get the text content of the message by specifying the message key.
1899 ### Format of the message file
1901 The message file is an ASCII file, which defines a set of messages. Each line of the file must have a length of less than 255 characters.
1902 All lines in the file starting with the exclamation sign (perhaps preceded by spaces and/or tabs) are considered as comments and are ignored.
1903 A message file may contain several messages. Each message is identified by its key (string).
1904 Each line in the file starting with the *dot* character (perhaps preceded by spaces and/or tabs) defines the key. The key is a string starting with a symbol placed after the dot and ending with the symbol preceding the ending of the newline character <i>\\n.</i>
1905 All lines in the file after the key and before the next keyword (and which are not comments) define the message for that key. If the message consists of several lines, the message string will contain newline symbols <i>\\n</i> between each line (but not at the end).
1907 The following example illustrates the structure of a message file:
1910 !This is a sample message file
1911 !------------------------------
1912 !Messages for ShapeAnalysis package
1915 Your message string goes here
1919 !End of the message file
1922 ### Loading the message file
1924 A custom file can be loaded into memory using the method *Message_MsgFile::LoadFile*, taking as an argument the path to your file as in the example below:
1926 Standard_CString MsgFilePath = ;(path)/sample.file;;
1927 Message_MsgFile::LoadFile (MsgFilePath);
1930 @subsection occt_shg_7_3 Tool for managing filling messages
1932 The class *Message_Msg* allows using the message file loaded as a template. This class provides a tool for preparing the message, filling it with parameters, storing and outputting to the default trace file.
1933 A message is created from a key: this key identifies the message to be created in the message file. The text of the message is taken from the loaded message file (class *Message_MsgFile* is used).
1934 The text of the message can contain places for parameters, which are to be filled by the proper values when the message is prepared. These parameters can be of the following types:
1935 * string -- coded in the text as \%s,
1936 * integer -- coded in the text as \%d,
1937 * real -- coded in the text as \%f.
1938 The parameter fields are filled by the message text by calling the corresponding methods *AddInteger, AddReal* and *AddString*. Both the original text of the message and the input text with substituted parameters are stored in the object. The prepared and filled message can be output to the default trace file. The text of the message (either original or filled) can be also obtained.
1940 Message_Msg msg01 (;SampleKeyword;);
1941 //Creates the message msg01, identified in the file by the keyword SampleKeyword
1942 msg1.AddInteger (73);
1943 msg1.AddString (;SampleFile;);
1944 //fills out the code areas
1947 @subsection occt_shg_7_4 Tool for managing trace files
1949 Class *Message_TraceFile* is intended to manage the trace file (or stream) for outputting messages and the current trace level. Trace level is an integer number, which is used when messages are sent. Generally, 0 means minimum, \> 0 various levels. If the current trace level is lower than the level of the message it is not output to the trace file. The trace level is to be managed and used by the users.
1950 There are two ways of using trace files:
1951 * define an object of *Message_TraceFile*, with its own definition (file name or cout, trace level), and use it where it is defined,
1952 * use the default trace file (file name or cout, trace level), usable from anywhere.
1953 Use the constructor method to define the target file and the level of the messages as in the example below:
1955 Message_TraceFile myTF
1956 (tracelevel, "tracefile.log", Standard_False);
1958 The parameters are as follows:
1959 * *tracelevel* is a Standard_Integer and modifies the level of messages. It has the following values and semantics:
1960 + 0: gives general information such as the start and end of process;
1961 + 1: gives exceptions raised and fail messages;
1962 + 2: gives the same information as 1 plus warning messages.
1963 * *filename* is the string containing the path to the log file.
1964 The Boolean set to False will rewrite the existing file. When set to True, new messages will be appended to the existing file.
1966 A new default log file can be added using method *SetDefault* with the same arguments as in the constructor.
1967 The default trace level can be changed by using method *SetDefLevel*. In this way, the information received in the log file is modified.
1968 It is possible to close the log file and set the default trace output to the screen display instead of the log file using the method *SetDefault* without any arguments.