-STEP processor {#user_guides__step}
+STEP processor {#occt_user_guides__step}
========================
@tableofcontents
5. fetch the results.
@subsection occt_step_2_2 Domain covered
@subsubsection occt_step_2_2_1 Assemblies
-The **ProSTEP Round Table Agreement Log** (version July 1998), item 21, defines two alternatives for the implementation of assembly structure representations: using mapped_item entities and using representation_relationship_with_transformation entities. Both these alternative representations are recognized and processed at reading. On writing, the second alternative is always employed.
+The **ProSTEP Round Table Agreement Log** (version July 1998), item 21, defines two alternatives for the implementation of assembly structure representations: using *mapped_item entities* and using *representation_relationship_with_transformation* entities. Both these alternative representations are recognized and processed at reading. On writing, the second alternative is always employed.
Handling of assemblies is implemented in two separate levels: firstly STEP assembly structures are translated into OCCT shapes, and secondly the OCCT shape representing the assembly is converted into any data structure intended for representing assemblies (for example, OCAF).
-The first part of this document describes the basic STEP translator implementing translation of the first level, i.e. translation to OCCT Shapes. On this level, the acyclic graph representing the assembly structure in a STEP file is mapped into the structure of nested TopoDS_Compounds in Open CASCADE Technology. The (sub)assemblies become (sub)compounds containing shapes which are the results of translating components of that (sub)assembly. The sharing of components of assemblies is preserved as Open CASCADE Technology sharing of subshapes in compounds.
+The first part of this document describes the basic STEP translator implementing translation of the first level, i.e. translation to OCCT Shapes. On this level, the acyclic graph representing the assembly structure in a STEP file is mapped into the structure of nested *TopoDS_Compounds* in Open CASCADE Technology. The (sub)assemblies become (sub)compounds containing shapes which are the results of translating components of that (sub)assembly. The sharing of components of assemblies is preserved as Open CASCADE Technology sharing of subshapes in compounds.
The attributive information attached to assembly components in a STEP file (such as names and descriptions of products, colors, layers etc.) can be translatd after the translation of the shape itself by parsing the STEP model (loaded in memory). Several tools from the package STEPConstruct provide functionalities to read styles (colors), validation properties, product information etc.
Implementation of the second level of translation (conversion to XDE data structure) is provided by XDE STEP translator.
@subsubsection occt_step_2_2_2 Shape representations
-Length units, plane angle units and the uncertainty value are taken from shape_representation entities. This data is used in the translation process.
+Length units, plane angle units and the uncertainty value are taken from *shape_representation* entities. This data is used in the translation process.
The types of STEP representation entities that are recognized are:
* advanced_brep_shape_representation
* *TopoDS_Shape shape = reader.Shape(rank)* gets the result identified by its rank, where rank is an integer between 1 and NbShapes;
* *TopoDS_Shape shape = reader.Shape()* gets the first result of translation;
* *TopoDS_Shape shape = reader.OneShape()* - gets all results in a single shape which is:
- * a null shape if there are no results,
- * in case of a single result, a shape that is specific to that result,
- * a compound that lists the results if there are several results.
+ * a null shape if there are no results,
+ * in case of a single result, a shape that is specific to that result,
+ * a compound that lists the results if there are several results.
<h5>Clearing the accumulation of results</h5>
* a list of entities,
* one entity.
-<h5>Whole file</h5>
+<h5>The whole file</h5>
Transferring the whole file means transferring all root entities. The number of roots can be evaluated when the file is loaded:
~~~~~
Standard_Integer num = reader.TransferRoots();
~~~~~
-<h4>List of entities</h4>
+<h5>List of entities</h5>
A list of entities can be formed by invoking *STEP214Control_Reader::GiveList* (this is a method of the parent class).
Here is a simple example of how a list is translated:
~~~~~
Standard_Integer i,nb = list->Length();
for (i = 1; i <= nb; i ++) {
- Handle(Standard_Transient) ent = list->Value(i);
- Standard_Boolean OK = reader.TransferEntity (ent);
+ Handle(Standard_Transient) ent = list->Value(i);
+ Standard_Boolean OK = reader.TransferEntity (ent);
}
~~~~~
@subsubsection occt_step_2_4_1 Assembly structure representation entities
Not all entities defining the assembly structure in the STEP file are translated to OCCT shapes, but they are used to identify the relationships between assemblies and their components. Since the graph of ‘natural’ dependencies of entities based on direct references between them does not include the references from assemblies to their components, these dependencies are introduced in addition to the former ones. This is made basing on the analysis of the following entities describing the structure of the assembly.
-| STEP entity type | CASCADE shape | Comments |
-
-product_definition For assemblies, a TopoDS_Compound,
-for components, a CASCADE shape corresponding to the type of component Each assembly or component has its own product_definition. It is used as a starting point for translation when read.step.product.mode is ON
-product_definition_shape This entity provides a link between product_definition and corresponding shape_definition_representation, or between next_assembly_usage_occurence and corresponding context_dependent_shape_representation
-shape_definition_representation For assemblies, a TopoDS_Compound,
-for components, a CASCADE shape corresponding to the type of component Each assembly or component has its own shape_definition_representation. The graph of dependencies is modified in such a way that shape_definition_representations of all components of the assembly are referred by the shape_definition_representation of the assembly.
-next_assembly_usage_occurence This entity defines a relationship between the assembly and its component. It is used to introduce (in the dependencies graph) the links between shape_definition_representation of the assembly and shape_definition_representations and context_dependent_shape_representations of all its components.
-mapped_item TopoDS_Shape This entity defines a mapping of the assembly component into the shape_representation of the assembly. The result of translation is a CASCADE shape translated from the component, to which transformation defined by the mapped_item is applied.
-context_dependent_shape_representation TopoDS_Shape This entity is associated with the next_assembly_usage_occurence entity and defines a placement of the component in the assembly. The graph of dependencies is modified so that each context_dependent_shape_representation is referred by shape_definition_representation of the corresponding assembly.
-shape_representation_relationship_with_transformation This entity is associated with context_dependent_shape_representation and defines a transformation necessary to apply to the component in order to locate it in its place in the assembly.
-item_defined_transformation This entity defines a transformation operator used by shape_representation_relationship_with_transformation or mapped_item entity
-cartesian_transformation_operator This entity defines a transformation operator used by shape_representation_relationship_with_transformation or mapped_item entity
+| STEP entity type | CASCADE shape | Comments |
+| :--------------- | :-------------- | :------ |
+| product_definition | A *TopoDS_Compound* for assemblies, a CASCADE shape corresponding to the component type of for components, | Each assembly or component has its own *product_definition*. It is used as a starting point for translation when *read.step.product.mode* is ON. |
+| product_definition_shape | | This entity provides a link between *product_definition* and corresponding *shape_definition_representation*, or between *next_assembly_usage_occurence* and corresponding *context_dependent_shape_representation*. |
+| shape_definition_representation | A TopoDS_Compound for assemblies, a CASCADE shape corresponding to the component type for components. | Each assembly or component has its own *shape_definition_representation*. The graph of dependencies is modified in such a way that *shape_definition_representations* of all components of the assembly are referred by the *shape_definition_representation* of the assembly. |
+| next_assembly_usage_occurence | | This entity defines a relationship between the assembly and its component. It is used to introduce (in the dependencies graph) the links between *shape_definition_representation* of the assembly and *shape_definition_representations* and *context_dependent_shape_representations* of all its components. |
+| mapped_item | TopoDS_Shape | This entity defines a mapping of the assembly component into the *shape_representation* of the assembly. The result of translation is a CASCADE shape translated from the component, to which transformation defined by the *mapped_item* is applied. |
+| context_dependent_shape_representation | TopoDS_Shape | This entity is associated with the *next_assembly_usage_occurence* entity and defines a placement of the component in the assembly. The graph of dependencies is modified so that each *context_dependent_shape_representation* is referred by shape_definition_representation of the corresponding assembly. |
+| shape_representation_relationship_with_transformation | | This entity is associated with *context_dependent_shape_representation* and defines a transformation necessary to apply to the component in order to locate it in its place in the assembly. |
+| item_defined_transformation | | This entity defines a transformation operator used by *shape_representation_relationship_with_transformation* or *mapped_item* entity |
+| cartesian_transformation_operator | | This entity defines a transformation operator used by *shape_representation_relationship_with_transformation* or *mapped_item* entity |
@subsubsection occt_step_2_4_2 Models
-STEP entity type CASCADE shape Comments
-Solid Models
-brep_with_voids TopoDS_Solid
-faceted_brep TopoDS_Solid
-manifold_solid_brep TopoDS_Solid
-Surface Models
-shell_based_surface_model TopoDS_Compound shell_based_surface_model is translated into one or more TopoDS_Shell grouped in a TopoDS_Compound
-geometric_set TopoDS_Compound TopoDS_Compound contains only TopoDS_Faces, TopoDS_Wires, TopoDS_Edges and/or TopoDS_Vertices
-Wireframe Models
-geometric_curve_set TopoDS_Compound TopoDS_Compound contains only TopoDS_Wires, TopoDS_Edges and/or TopoDS_Vertices
+| STEP entity type | CASCADE shape | Comments |
+| :-------------- | :----------- | :---------- |
+| Solid Models | | |
+| brep_with_voids | TopoDS_Solid | |
+| faceted_brep | TopoDS_Solid | |
+| manifold_solid_brep | TopoDS_Solid | |
+| Surface Models | | |
+| shell_based_surface_model | TopoDS_Compound | *shell_based_surface_model* is translated into one or more *TopoDS_Shell* grouped in a *TopoDS_Compound* |
+| geometric_set | TopoDS_Compound | *TopoDS_Compound* contains only *TopoDS_Faces*, *TopoDS_Wires*, *TopoDS_Edges* and/or *TopoDS_Vertices*.
+| Wireframe Models | | |
+| geometric_curve_set | TopoDS_Compound | *TopoDS_Compound* contains only *TopoDS_Wires*, *TopoDS_Edges* and/or *TopoDS_Vertices*.
@subsubsection occt_step_2_4_3 Topological entities
-STEP entity type CASCADE shape Comments
-Vertices
-vertex_point TopoDS_Vertex
-Edges
-oriented_edge TopoDS_Edge
-edge_curve TopoDS_Edge
-Loops
-face_bound TopoDS_Wire
-face_outer_bound TopoDS_Wire
-edge_loop TopoDS_Wire
-poly_loop TopoDS_Wire Each segment of poly_loop is translated into TopoDS_Edge with support of Geom_Line
-vertex_loop TopoDS_Wire Resulting TopoDS_Wire contains only one degenerated TopoDS_Edge
-Faces
-face_surface TopoDS_Face
-advanced_face TopoDS_Face
-Shells
-connected_face_set TopoDS_Shell
-oriented_closed_shell TopoDS_Shell
-closed_shell TopoDS_Shell
-open_shell TopoDS_Shell
+| Topology | STEP entity type | CASCADE shape | Comments |
+| :------- | :--------- | :-------- | :----- |
+| Vertices | vertex_point | TopoDS_Vertex | |
+| Edges | oriented_edge | TopoDS_Edge | |
+| | edge_curve | TopoDS_Edge | |
+| Loops | face_bound | TopoDS_Wire | |
+| | face_outer_bound | TopoDS_Wire | |
+| | edge_loop | TopoDS_Wire | |
+| | poly_loop | TopoDS_Wire | Each segment of *poly_loop* is translated into *TopoDS_Edge* with support of *Geom_Line* |
+| | vertex_loop | TopoDS_Wire | Resulting *TopoDS_Wire* contains only one degenerated *TopoDS_Edge* |
+| Faces | face_surface | TopoDS_Face | |
+| | advanced_face | TopoDS_Face | |
+| Shells | connected_face_set | TopoDS_Shell | |
+| | oriented_closed_shell | TopoDS_Shell | |
+| | closed_shell | TopoDS_Shell | |
+| | open_shell | TopoDS_Shell | |
@subsubsection occt_step_2_4_4 Geometrical entities
-3D STEP entities are translated into geometrical objects from the Geom package while 2D entities are translated into objects from the Geom2d package.
-STEP entity type CASCADE object Comments
-Points
-cartesian_point Geom_CartesianPoint
- Geom2d_CartesianPoint
-Directions
-direction Geom_Direction
- Geom2d_Direction
-Vectors
-vector Geom_VectorWithMagnitude
- Geom2d_VectorWithMagnitude
-Placements
-axis1_placement Geom_Axis1Placement
-axis2_placement_2d Geom2d_AxisPlacement
-axis2_placement_3d Geom_Axis2Placement
-Curves
-circle Geom_Circle
- Geom2d_Circle
- Geom2d_BsplineCurve Circle is translated into Geom2d_BSplineCurve when it references the surface of revolution (spherical surface, conical surface, etc.)
-ellipse Geom_Ellipse
- Geom2d_Ellipse
- Geom2d_BsplineCurve Ellipse is translated into Geom2d_BSplineCurve when it references the surface of revolution (spherical surface, conical surface, etc.)
-hyperbola Geom_Hyperbola
- Geom2d_Hyperbola
-line Geom_Line
- Geom2d_Line
-parabola Geom_Parabola
- Geom2d_Parabola
-pcurve Geom2d_Curve Pcurve in edge
-curve_replica Geom_Curve Depending on the type of basis curve
- Geom2d_Curve
-offset_curve_3d Geom_OffsetCurve
-trimmed_curve Geom_TrimmedCurve
- Geom2d_BsplineCurve Only trimmed_curves trimmed by parameters are translated. All trimmed_curves are converted to Geom2d_BSplineCurve.
-b_spline_curve Geom_BsplineCurve
- Geom2d_BsplineCurve
-b_spline_curve_with_
-knots Geom_BsplineCurve
- Geom2d_BsplineCurve
-bezier_curve Geom_BsplineCurve
- Geom2d_BsplineCurve
-rational_b_spline_curve Geom_BsplineCurve
- Geom2d_BsplineCurve
-uniform_curve Geom_BsplineCurve
- Geom2d_BsplineCurve
-quasi_ uniform_curve Geom_BsplineCurve
- Geom2d_BsplineCurve
-surface_curve TopoDS_Edge surface_curve defines geometrical support of an edge and its pcurves.
-seam_curve TopoDS_Edge the same as surface_curve
-composite_curve_segment TopoDS_Edge as a segment of composite_curve
-composite_curve TopoDS_Wire
-composite_curve_on_surface TopoDS_Wire
-boundary_curve TopoDS_Wire
-Surfaces
-b_spline_surface Geom_BsplineSurface
-b_spline_surface_with_knots Geom_BsplineSurface
-bezier_surface Geom_BSplineSurface
-conical_surface Geom_ConicalSurface
-cylindrical_surface Geom_CylindricalSurface
-offset_surface Geom_OffsetSurface
-surface_replica Geom_Surface Depending on the type of basis surface
-plane Geom_Plane
-rational_b_spline_surface Geom_BSplineSurface
-rectangular_trimmed_
-surface Geom_RectangularTrimmedSurface
-spherical_surface Geom_SphericalSurface
-surface_of_linear_extrusion Geom_SurfaceOfLinearExtrusion
-surface_of_revolution Geom_SurfaceOfRevolution
-toroidal_surface Geom_ToroidalSurface
-degenerate_toroidal_surface Geom_ToroidalSurface
-uniform_surface Geom_BSplineSurface
-quasi_uniform_surface Geom_BSplineSurface
-rectangular_composite_surface TopoDS_Compound Contains TopoDS_Faces
-curve_bounded_surface TopoDS_Face
+3D STEP entities are translated into geometrical objects from the *Geom* package while 2D entities are translated into objects from the *Geom2d* package.
+| Geometry | STEP entity type | CASCADE object | Comments |
+| :------ | :-------- | :------ | :-------- |
+| Points | cartesian_point | Geom_CartesianPoint, Geom2d_CartesianPoint | |
+| Directions | direction | Geom_Direction, Geom2d_Direction | |
+| Vectors | vector | Geom_VectorWithMagnitude, Geom2d_VectorWithMagnitude | |
+| Placements | axis1_placement | Geom_Axis1Placement | |
+| | axis2_placement_2d | Geom2d_AxisPlacement | |
+| | axis2_placement_3d | Geom_Axis2Placement | |
+| Curves | circle | Geom_Circle, Geom2d_Circle, Geom2d_BsplineCurve | Circle is translated into *Geom2d_BSplineCurve* when it references the surface of revolution (spherical surface, conical surface, etc.) |
+| | ellipse | Geom_Ellipse, Geom2d_Ellipse, Geom2d_BsplineCurve | Ellipse is translated into *Geom2d_BSplineCurve* when it references the surface of revolution (spherical surface, conical surface, etc.) |
+| | hyperbola | Geom_Hyperbola, Geom2d_Hyperbola | |
+| | line | Geom_Line, Geom2d_Line | |
+| | parabola | Geom_Parabola, Geom2d_Parabola | |
+| | pcurve | Geom2d_Curve | Pcurve in edge |
+| | curve_replica | Geom_Curve or Geom2d_Curve | Depending on the type of the base curve |
+| | offset_curve_3d | Geom_OffsetCurve | |
+| | trimmed_curve | Geom_TrimmedCurve or Geom2d_BsplineCurve | Only trimmed_curves trimmed by parameters are translated. All *trimmed_curves* are converted to *Geom2d_BSplineCurve*. |
+| | b_spline_curve | Geom_BsplineCurve or Geom2d_BsplineCurve | |
+| | b_spline_curve_with_knots | Geom_BsplineCurve or Geom2d_BsplineCurve | |
+| | bezier_curve | Geom_BsplineCurve or Geom2d_BsplineCurve | |
+| | rational_b_spline_curve | Geom_BsplineCurve or Geom2d_BsplineCurve | |
+| | uniform_curve | Geom_BsplineCurve or Geom2d_BsplineCurve | |
+| | quasi_ uniform_curve | Geom_BsplineCurve or Geom2d_BsplineCurve | |
+| | surface_curve | TopoDS_Edge | *surface_curve* defines geometrical support of an edge and its pcurves. |
+| | seam_curve | TopoDS_Edge | The same as *surface_curve* |
+| | composite_curve_segment | TopoDS_Edge | as a segment of *composite_curve* |
+| | composite_curve | TopoDS_Wire | |
+| | composite_curve_on_surface | TopoDS_Wire | |
+| | boundary_curve | TopoDS_Wire | |
+| Surfaces | b_spline_surface | Geom_BsplineSurface | |
+| | b_spline_surface_with_knots | Geom_BsplineSurface | |
+| | bezier_surface | Geom_BSplineSurface | |
+| | conical_surface | Geom_ConicalSurface | |
+| | cylindrical_surface | Geom_CylindricalSurface | |
+| | offset_surface | Geom_OffsetSurface | |
+| | surface_replica | Geom_Surface | Depending on the type of basis surface |
+| | plane | Geom_Plane | |
+| | rational_b_spline_surface | Geom_BSplineSurface | |
+| | rectangular_trimmed_surface | Geom_RectangularTrimmedSurface | |
+| | spherical_surface | Geom_SphericalSurface | |
+| | surface_of_linear_extrusion | Geom_SurfaceOfLinearExtrusion | |
+| | surface_of_revolution | Geom_SurfaceOfRevolution | |
+| | toroidal_surface | Geom_ToroidalSurface | |
+| | degenerate_toroidal_surface | Geom_ToroidalSurface | |
+| | uniform_surface | Geom_BSplineSurface | |
+| | quasi_uniform_surface | Geom_BSplineSurface | |
+| | rectangular_composite_surface | TopoDS_Compound | Contains *TopoDS_Faces* |
+| | curve_bounded_surface | TopoDS_Face | |
@subsection occt_step_2_5 Tolerance management
@subsubsection occt_step_2_5_1 Values used for tolerances during reading STEP
-During the STEP = OCCT translation several parameters are used as tolerances and precisions for different algorithms. Some of them are computed from other tolerances using specific functions.
+During the STEP to OCCT translation several parameters are used as tolerances and precisions for different algorithms. Some of them are computed from other tolerances using specific functions.
<h4>3D (spatial) tolerance</h4>
* Package method *Precision::Confusion()* Value is 10-7. It is used as the minimal distance between points, which are considered to be distinct.
* User - defined variable *read.precision.val* is used instead of uncertainty from a STEP file when parameter *read.precision.mode* is 1 (User).
<h4>2D (parametric) tolerances</h4>
-* Package method *Precision::PConfusion()* is a value of *0.01\*Precision::Confusion()*. It is used to compare parametric bounds of curves.
+* Package method *Precision\::PConfusion()* is a value of *0.01\*Precision\::Confusion()*. It is used to compare parametric bounds of curves.
* Methods *UResolution* and *VResolution (tolerance3d)* of the class *GeomAdaptor_Surface* or *BRepAdaptor_Surface* - return tolerance in parametric space of a surface computed from 3d tolerance. When one tolerance value is to be used for both U and V parametric directions, the maximum or the minimum value of *UResolution* and *VResolution* is used.
* Methods *Resolution (tolerance3d)* of the class *GeomAdaptor_Curve* or *BRepAdaptor_Curve* return tolerance in parametric space of a curve computed from 3d tolerance.
If the starting STEP entity is not a geometric_curve_set the sub-shapes of the resulting shape have the following tolerance:
* all the faces are constructed with *Precision::Confusion()*,
* edges are constructed with *Precision::Confusion()*. It can be modified later by:
- * *ShapeFix::SameParameter()* - the tolerance of edge shows real deviation of the 3D curve and pcurves.
- * *ShapeFix_Wire::FixSelfIntersection()* if a pcurve of a self-intersecting edge is modified.
+ * *ShapeFix::SameParameter()* - the tolerance of edge shows real deviation of the 3D curve and pcurves.
+ * *ShapeFix_Wire::FixSelfIntersection()* if a pcurve of a self-intersecting edge is modified.
* vertices are constructed with Precision::Confusion(). It can be modified later by:
- *StepToTopoDS_TranslateEdge*
- *ShapeFix::SameParameter()*
- *ShapeFix_Wire::FixSelfIntersection()*
- *ShapeFix_Wire::FixLacking()*
- *ShapeFix_Wire::Connected()*
-
+ *StepToTopoDS_TranslateEdge*
+ *ShapeFix::SameParameter()*
+ *ShapeFix_Wire::FixSelfIntersection()*
+ *ShapeFix_Wire::FixLacking()*
+ *ShapeFix_Wire::Connected()*
+
So, the final tolerance of sub-shapes shows the real local geometry of shapes (distance between vertices of adjacent edges, deviation of a 3D curve of an edge and its parametric curves and so on) and may be less or greater than the basic value of tolerance in the STEP processor.
<h4>Translating into Geometry</h4>
@subsection occt_step_2_7 Example
~~~~~
-#include STEPControl_Reader.hxx
-#include TopoDS_Shape.hxx
-#include BRepTools.hxx
+#include <STEPControl_Reader.hxx>
+#include <TopoDS_Shape.hxx>
+#include <BRepTools.hxx>
Standard_Integer main()
{
@subsubsection occt_step_3_2_2 Writing assembly structures
The shapes organized in a structure of nested compounds can be translated either as simple compound shapes, or into the assembly structure, depending on the parameter *write.step.assembly*, which is described below.
-The assembly structure placed in the produced STEP file corresponds to the structure described in the ProSTEP Agreement Log (item 21) as the second alternative (assembly structure through representation_relationship / item_defined_transformation). To represent an assembly it uses entities of the representation_relationship_with_transformation type. Transformation operators used for locating assembly components are represented by item_defined_transformation entities.
-If mode ;write.step.assembly; is set to the values ON or Auto then an OCC shape consisting of nested compounds will be written as an assembly, otherwise it will be written as separate solids.
+The assembly structure placed in the produced STEP file corresponds to the structure described in the ProSTEP Agreement Log (item 21) as the second alternative (assembly structure through *representation_relationship* / *item_defined_transformation*). To represent an assembly it uses entities of the *representation_relationship_with_transformation* type. Transformation operators used for locating assembly components are represented by *item_defined_transformation* entities.
+If mode *write.step.assembly* is set to the values *ON* or *Auto* then an OCC shape consisting of nested compounds will be written as an assembly, otherwise it will be written as separate solids.
Please see also <a href="#occt_step_3_4">Mapping OCCT shapes to STEP entities</a>
* 2 or ;AP214DIS;: AP214, DIS version (dated 15 September 1998).
* 3 or ;AP203;: AP203, possibly with modular extensions (depending on data written to a file).
* 4 or *AP214IS*: AP214, IS version (dated 2002)
-This parameter affects the following entities written to the STEP file:
-
-AP214, CD version AP214, DIS version AP214,IS version AP203
-FILE_SCHEMA( (`AUTOMOTIVE_DESIGN_CC2 { 1 2 10303 214 -1 1 5 4}')) FILE_SCHEMA( (`AUTOMOTIVE_DESIGN { 1 2 10303 214 0 1 1 1}')) FILE_SCHEMA(
-('AUTOMOTIVE_DESIGN
- { 1 0 10303 214 1 1 1 1 }')) FILE_SCHEMA( (`CONFIG_CONTROL_DESIGN'))
-APPLICATION_PROTOCOL_ DEFINITION
-`committee draft',
-`automotive_design'
-,1997,##) APPLICATION_PROTOCOL_ DEFINITION(
-'draft international standard',
-'automotive_design',
-1998,##) APPLICATION_PROTOCOL_DEFINITION
-('international standard', ‘automotive_design',
-2000,##); APPLICATION_PROTOCOL_ DEFINITION
-('international standard', 'config_control_design',1994,##)
-APPLICATION_CONTEXT( 'core data for automotive mechanical design processes') APPLICATION_CONTEXT( ‘configuration controlled 3D designs of mechanical parts and assemblies' )
-PRODUCT_TYPE(`part',$,(##)) PRODUCT_RELATED_PRODUCT_CATEGORY( `part',$,(##))
-MECHANICAL_CONTEXT(`',##, 'mechanical') PRODUCT_CONTEXT(`',##, 'mechanical') PRODUCT_CONTEXT('',##,'mechanical'); MECHANICAL_CONTEXT(`',##, 'mechanical')
-
-In addition, in AP203 mode more product and organizational entities are generated (entities like PERSON_AND_ORGANIZATION, SECURITY_CLASSIFICATION etc., as required by AP203).
+
Read this parameter with:
~~~~~
TCollection_AsciiString schema = Interface_Static::CVal("write.step.schema");
Default values:
* read.step.resource.name - STEP,
* read.step.sequence - ToSTEP.
+
+<h4>write.step.vertex.mode</h4>
+This parameter indicates which of free vertices writing mode is switch on.
+* 0 (One Compound) : (default) All free vertices are united into one compound and exported in one SHAPE DEFINITION REPRESENTATION (vertex name and style are lost).
+* 1 (Single Vertex) : Each vertex exported in its own SHAPE DEFINITION REPRESENTATION (vertex name and style are not lost, but size of STEP file increases).
+
+Read this parameter with:
+~~~~~
+Standard_Integer ic = Interface_Static::IVal("write.step.vertex.mode");
+~~~~~
+Modify this parameter with:
+~~~~~
+if(!Interface_Static::SetIVal("write.step.vertex.mode",1))
+.. error ..
+~~~~~
+Default value is 0.
@subsubsection occt_step_3_3_3 Performing the Open CASCADE Technology shape translation
An OCCT shape can be translated to STEP using one of the following models (shape_representations):
* shell_based_surface_model (manifold_surface_shape_representation)
* geometric_curve_set (geometrically_bounded_wireframe_shape_representation)
-The enumeration **TEPControl_StepModelType* is intended to define a particular transferring model.
+The enumeration *STEPControl_StepModelType* is intended to define a particular transferring model.
The following values of enumeration are allowed:
-* *STEPControl_AsIs* Translator selects the resulting representation automatically, according to the type of CASCADE shape to translate it in its highest possible model;
-* *STEPControl_ManifoldSolidBrep* resulting entity is manifold_solid_brep or brep_with_voids
-* *STEPControl_FacetedBrep* resulting entity is *faceted_brep* or *faceted_brep_and_brep_with_voids* Note that only planar-face shapes with linear edges can be written;
+* *STEPControl_AsIs* Translator selects the resulting representation automatically, according to the type of CASCADE shape to translate it in its highest possible model;
+* *STEPControl_ManifoldSolidBrep* resulting entity is manifold_solid_brep or brep_with_voids
+* *STEPControl_FacetedBrep* resulting entity is *faceted_brep* or *faceted_brep_and_brep_with_voids* Note that only planar-face shapes with linear edges can be written;
* *STEPControl_ShellBasedSurfaceModel* resulting entity is *shell_based_surface_model*;
-* *STEPControl_GeometricCurveSet* resulting entity is *geometric_curve_set*;
+* *STEPControl_GeometricCurveSet* resulting entity is *geometric_curve_set*;
-The following table shows which shapes can be translated in which mode:
-* *STEP214Control_AsIs* - any OCCT shape
-* *STEP214Control_ManifoldSolidBrep* - *TopoDS_Solid, TopoDS_Shell, TopoDS_Compound* (if it contains *TopoDS_Solids* and *TopoDS_Shells*.
-* *STEP214Control_FacetedBrep* - *TopoDS_Solid* or *TopoDS_Compound* containing *TopoDS_Solids* if all its surfaces are *Geom_Planes* and all curves are *Geom_Lines*.
+The following list shows which shapes can be translated in which mode:
+* *STEP214Control_AsIs* - any OCCT shape
+* *STEP214Control_ManifoldSolidBrep* - *TopoDS_Solid, TopoDS_Shell, TopoDS_Compound* (if it contains *TopoDS_Solids* and *TopoDS_Shells*.
+* *STEP214Control_FacetedBrep* - *TopoDS_Solid* or *TopoDS_Compound* containing *TopoDS_Solids* if all its surfaces are *Geom_Planes* and all curves are *Geom_Lines*.
* *STEP214Control_ShellBasedSurfaceModel* - *TopoDS_Solid, TopoDS_Shell, TopoDS_Face* and *TopoDS_Compound* (if it contains all mentioned shapes)
* *STEP214Control_GeometricCurveSet* - any OCCT shape.
The table below describes STEP entities, which are created when the assembly structure and product information are written to the STEP file, and shows how many of these entities are created. Note that the appearance of some of these entities depends on the version of the schema (AP214, CD, DIS or IS, or AP203).
-CASCADE shape STEP entity Comments
- application_protocol_definition One per STEP file, defines the application protocol used (depends on the schema version)
- application_context One per STEP file, defines the application generating the file (AP214 or AP203)
-TopoDS_Compound shape_representation Empty shape_representation describing the assembly. The components of that assembly are written as subtypes of shape_representation and are included to the assembly using next_assembly_usage_occurence entities.
-TopoDS_Shape subtypes of shape_representation Depending on the shape type, see the tables below for mapping details
- next_assembly_usage_occurence Describes the instance of component in the assembly by referring corresponding product_definitions. If the same component is included in the assembly several times (for example, with different locations), several next_assembly_usage_occurences are created.
- context_dependent_shape_representation Describes the placement of a component in the assembly. One context_dependent_shape_ representation corresponds to each next_assembly_usage_occurence entity.
- shape_representation_relationship_with_transformation Together with the context_dependent_shape_ representation describes the location of a component in the assembly.
- item_defined_transformation Defines a transformation used for the location of a component in the assembly. Is referred by shape_representation_relationship_with_transformation
- shape_definition_representation One per shape_representation
- product_definition_shape One per shape_definition_representation and context_dependent_shape_representation
- product_definition Defines a product, one per shape_definition_representation
- product_definition_formation One per product_definition. All product_definition_formations in the STEP file have unique names.
- Product One per product_definition_formation. All products in the STEP file have unique names.
- product_type (CD) or product_related_product_category (DIS,IS) One per product
- Mechanical_context (CD) or product_context (DIS,IS) One per product.
- product_definition_context One per product_definition.
+| CASCADE shape | STEP entity | Comments |
+| :--------- | :------ | :----- |
+| | application_protocol_definition | One per STEP file, defines the application protocol used (depends on the schema version) |
+| | application_context | One per STEP file, defines the application generating the file (AP214 or AP203) |
+| TopoDS_Compound | shape_representation | Empty *shape_representation* describing the assembly. The components of that assembly are written as subtypes of shape_representation and are included to the assembly using *next_assembly_usage_occurence* entities. |
+| TopoDS_Shape | subtypes of shape_representation | Depending on the shape type, see the tables below for mapping details |
+| | next_assembly_usage_occurence | Describes the instance of component in the assembly by referring corresponding *product_definitions*. If the same component is included in the assembly several times (for example, with different locations), several *next_assembly_usage_occurences* are created. |
+| | context_dependent_shape_representation | Describes the placement of a component in the assembly. One *context_dependent_shape_representation* corresponds to each *next_assembly_usage_occurence* entity. |
+| | shape_representation_relationship_with_transformation | Together with the *context_dependent_shape_representation* describes the location of a component in the assembly. |
+| | item_defined_transformation | Defines a transformation used for the location of a component in the assembly. Is referred by *shape_representation_relationship_with_transformation*. |
+| | shape_definition_representation | One per *shape_representation*. |
+| | product_definition_shape | One per *shape_definition_representation* and *context_dependent_shape_representation* |
+| | product_definition | Defines a product, one per *shape_definition_representation* |
+| | product_definition_formation | One per *product_definition*. All *product_definition_formations* in the STEP file have unique names. |
+| | Product | One per *product_definition_formation*. All products in the STEP file have unique names. |
+| | product_type (CD) or product_related_product_category (DIS,IS) | One per product |
+| | Mechanical_context (CD) or product_context (DIS,IS) | One per product. |
+| | product_definition_context | One per *product_definition*. |
@subsubsection occt_step_3_4_2 Topological shapes
-CASCADE shape STEP entity Comments
-TopoDS_Compound geometric_curve_set If the write mode is STEP214Control_GeometricCurveSet only 3D curves of the edges found in TopoDS_Compound and all its subshapes are translated
- manifold_solid_brep If the write mode is STEP214Control_AsIs and TopoDS_Compound consists only of TopoDS_Solids
- shell_based_surface_model If the write mode is STEP214Control_AsIs and TopoDS_Compound consists of TopoDS_Solids, TopoDS_Shells and TopoDS_Faces
- geometric_curve_set If the write mode is STEP214Control_AsIs and TopoDS_Compound contains TopoDS_Wires, TopoDS_Edges, TopoDS_Vertices
- If the write mode is not STEP214Control_AsIs or STEP214Control_GeometricCurveSet TopoDS_Solids, TopoDS_Shells and TopoDS_Faces are translated according to this table.
-TopoDS_Solid manifold_solid_brep If the write mode is STEP214Control_AsIs or STEP214Control_ManifoldSolidBrep and CASCADE TopoDS_Solid has no voids.
- faceted_brep If the write mode is STEP214Control_FacetedBrep.
- brep_with_voids If the write mode is STEP214Control_AsIs or STEP214Control_ManifoldSolidBrep and CASCADE TopoDS_Solid has voids.
- shell_based_surface_model If the write mode is STEP214Control_ShellBasedSurfaceModel.
- geometric_curve_set If the write mode is STEP214Control_GeometricCurveSet. Only 3D curves of the edges are translated.
-TopoDS_Shell in a TopoDS_Solid closed_shell If TopoDS_Shell is closed shell.
-TopoDS_Shell manifold_solid_brep If the write mode is STEP214Control_ManifoldSolidBrep.
- shell_based_surface_model If the write mode is STEP214Control_AsIs or STEP214Control_ShellBasedSurfaceModel.
- geometric_curve_set If the write mode is STEP214Control_GeometricCurveSet. Only 3D curves of the edges are translated.
-TopoDS_Face advanced_face
-TopoDS_Wire in a TopoDS_Face face_bound The resulting face_bound contains poly_loop if write mode is faceted_brep or edge_loop if not .
-TopoDS_Wire geometric_curve_set If the write mode is STEP214Control_GeometricCurveSet. Only 3D curves of the edges are translated.
-TopoDS_Edge oriented_edge
-TopoDS_Vertex vertex_point
+| CASCADE shape | STEP entity | Comments |
+| :----- | :---- | :----- |
+| TopoDS_Compound | geometric_curve_set | If the write mode is *STEP214Control_GeometricCurveSet* only 3D curves of the edges found in *TopoDS_Compound* and all its subshapes are translated |
+| | manifold_solid_brep | If the write mode is *STEP214Control_AsIs* and *TopoDS_Compound* consists only of *TopoDS_Solids*. |
+| | shell_based_surface_model | If the write mode is *STEP214Control_AsIs* and *TopoDS_Compound* consists of *TopoDS_Solids*, *TopoDS_Shells* and *TopoDS_Faces*.|
+| | geometric_curve_set | If the write mode is *STEP214Control_AsIs* and *TopoDS_Compound* contains *TopoDS_Wires, TopoDS_Edges, TopoDS_Vertices*. If the write mode is not *STEP214Control_AsIs* or *STEP214Control_GeometricCurveSet*, *TopoDS_Solids, TopoDS_Shells* and *TopoDS_Faces* are translated according to this table. |
+| TopoDS_Solid | manifold_solid_brep | If the write mode is *STEP214Control_AsIs* or *STEP214Control_ManifoldSolidBrep* and CASCADE *TopoDS_Solid* has no voids. |
+| | faceted_brep | If the write mode is *STEP214Control_FacetedBrep*. |
+| | brep_with_voids | If the write mode is *STEP214Control_AsIs* or *STEP214Control_ManifoldSolidBrep* and CASCADE *TopoDS_Solid* has voids. |
+| | shell_based_surface_model | If the write mode is *STEP214Control_ShellBasedSurfaceModel*. |
+| | geometric_curve_set | If the write mode is *STEP214Control_GeometricCurveSet*. Only 3D curves of the edges are translated. |
+| TopoDS_Shell in a TopoDS_Solid | closed_shell | If *TopoDS_Shell* is closed shell. |
+| TopoDS_Shell | manifold_solid_brep | If the write mode is *STEP214Control_ManifoldSolidBrep*. |
+| | shell_based_surface_model | If the write mode is *STEP214Control_AsIs* or *STEP214Control_ShellBasedSurfaceModel*. |
+| | geometric_curve_set | If the write mode is *STEP214Control_GeometricCurveSet*. Only 3D curves of the edges are translated. |
+| TopoDS_Face | advanced_face | |
+| TopoDS_Wire in a TopoDS_Face | face_bound | The resulting *face_bound* contains *poly_loop* if write mode is *faceted_brep* or *edge_loop* if it is not. |
+| TopoDS_Wire | geometric_curve_set | If the write mode is *STEP214Control_GeometricCurveSet*. Only 3D curves of the edges are translated. |
+| TopoDS_Edge | oriented_edge | |
+| TopoDS_Vertex | vertex_point | |
@subsubsection occt_step_3_4_3 Geometrical objects
-CASCADE object STEP entity Comments
-Points
-Geom_CartesianPoint cartesian_point
-Geom2d_CartesianPoint
-TColgp_Array1OfPnt polyline
-TColgp_Array1OfPnt2d
-Placements
-Geom_Axis1Plasement axis1_placement
-Geom2d_AxisPlacement
-Geom_Axis2Placement axis2_placement_3d
-Directions
-Geom_Direction direction
-Geom2d_Direction
-Vectors
-Geom_Vector vector
-Geom2d_Vector
-Curves
-Geom_Circle circle
-Geom2d_Circle circle
- rational_b_spline_curve
-Geom_Ellipse Ellipse
-Geom2d_Ellipse Ellipse
- rational_b_spline_curve
-Geom_Hyperbola Hyperbola
-Geom2d_Hyperbola
-Geom_Parabola Parabola
-Geom2d_Parabola
-Geom_BSplineCurve b_spline_curve_with_knots
- rational_b_spline_curve if Geom_BsplineCurve is a rational BSpline
-Geom2d_BSplineCurve b_spline_curve_with_knots
- b_spline_curve_with_knots_ and_rational_b_spline_curve if Geom2d_BSplineCurve is a rational Bspline
-Geom_BezierCurve b_spline_curve_with_knots
-Geom_Line Line
-Geom2d_Line
-Surfaces
-Geom_Plane Plane
-Geom_OffsetSurface offset_surface
-Geom_ConicalSurface conical_surface
-Geom_CylindricalSurface cylindrical_surface
-Geom_OffsetSurface offset_surface
-Geom_RectangularTrimmedSurface rectangular_trimmed_surface
-Geom_SphericalSurface spherical_surface
-Geom_SurfaceOfLinear Extrusion surface_of_linear_extrusion
-Geom_SurfaceOf Revolution surface_of_revolution
-Geom_ToroidalSurface toroidal_surface
- degenerate_toroidal_surface if the minor radius is greater then the major one
-Geom_BezierSurface b_spline_surface_with_knots
-Geom_BsplineSurface b_spline_surface_with_knots
- b_spline_surface_with_knots_ and_rational_b_spline_surface if Geom_BSplineSurface is a rational Bspline
+| Geometry | CASCADE object | STEP entity | Comments |
+| :----- | :------ | :----- | :----- |
+| Points | Geom_CartesianPoint, Geom2d_CartesianPoint | cartesian_point | |
+| | TColgp_Array1OfPnt, TColgp_Array1OfPnt2d | polyline | |
+| Placements | Geom_Axis1Plasement, Geom2d_AxisPlacement | axis1_placement | |
+| | Geom_Axis2Placement | axis2_placement_3d | |
+| Directions | Geom_Direction, Geom2d_Direction | direction | |
+| Vectors | Geom_Vector, Geom2d_Vector | vector | |
+| Curves | Geom_Circle | circle | |
+| | Geom2d_Circle | circle, rational_b_spline_curve | |
+| | Geom_Ellipse | Ellipse | |
+| | Geom2d_Ellipse | Ellipse, rational_b_spline_curve | |
+| | Geom_Hyperbola, Geom2d_Hyperbola | Hyperbola | |
+| | Geom_Parabola, Geom2d_Parabola | Parabola | |
+| | Geom_BSplineCurve | b_spline_curve_with_knots or rational_b_spline_curve | *rational_b_spline_curve* is produced if *Geom_BsplineCurve* is a rational BSpline |
+| | Geom2d_BSplineCurve | b_spline_curve_with_knots or rational_b_spline_curve | *rational_b_spline_curve* is produced if *Geom2d_BsplineCurve* is a rational BSpline |
+| | Geom_BezierCurve | b_spline_curve_with_knots | |
+| | Geom_Line or Geom2d_Line | Line | |
+| Surfaces | Geom_Plane | Plane | |
+| | Geom_OffsetSurface | offset_surface | |
+| | Geom_ConicalSurface | conical_surface | |
+| | Geom_CylindricalSurface | cylindrical_surface | |
+| | Geom_OffsetSurface | offset_surface | |
+| | Geom_RectangularTrimmedSurface | rectangular_trimmed_surface | |
+| | Geom_SphericalSurface | spherical_surface | |
+| | Geom_SurfaceOfLinear Extrusion | surface_of_linear_extrusion | |
+| | Geom_SurfaceOf Revolution | surface_of_revolution | |
+| | Geom_ToroidalSurface | toroidal_surface or degenerate_toroidal_surface | *degenerate_toroidal_surface* is produced if the minor radius is greater then the major one |
+| | Geom_BezierSurface | b_spline_surface_with_knots | |
+| | Geom_BsplineSurface | b_spline_surface_with_knots or rational_b_spline_surface | *rational_b_spline_surface* is produced if *Geom_BSplineSurface* is a rational Bspline |
@subsection occt_step_3_5 Tolerance management
@subsection occt_step_3_7 Example
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.cpp}
-#include STEPControl.hxx
-#include STEPControl_Writer.hxx
-#include TopoDS_Shape.hxx
-#include BRepTools.hxx
-#include BRep_Builder.hxx
+#include <STEPControl.hxx>
+#include <STEPControl_Writer.hxx>
+#include <TopoDS_Shape.hxx>
+#include <BRepTools.hxx>
+#include <BRep_Builder.hxx>
Standard_Integer main()
{
* Create the *RWStepxxx_RWNewEntity* class with a default constructor and methods *ReadStep()*, *WriteStep()* and if the entity references other entities, then method *Share()*.
* Update file *StepAP214_Protocol.cxx*. In the constructor *StepAP214_Protocol::StepAP214_Protocol()* add the new type to the map of registered types and associate the unique integer identifier with this type.
* Update file *RWStepAP214_ReadWriteModule.cxx*. The changes should be the following:
- * For simple types:
- * Add a static object of class *TCollection_AsciiString* with name *Reco_NewEntity* and initialize it with a string containing the STEP type.
- * In constructor *WStepAP214_ReadWriteModule::RWStepAP214_ReadWriteModule()* add this object onto the list with the unique integer identifier of the new entity type.
- * In function *RWStepAP214_ReadWriteModule::StepType()* add a new C++ case operator for this identifier.
- * For complex types:
- * In the method *RWStepAP214_ReadWriteModule::CaseStep()* add a code for recognition the new entity type returning its unique integer identifier.
- * In the method *RWStepAP214_ReadWriteModule::IsComplex()* return True for this type.
- * In the method *RWStepAP214_ReadWriteModule::ComplexType()* fill the list of subtypes composing this complex type.
- * For both simple and complex types:
- * In function *RWStepAP214_ReadWriteModule::ReadStep()* add a new C++ case operator for the new identifier and call the *RWStepxxx_RWNewEntity* class, method *ReadStep* to initialize the new class.
+ * For simple types:
+ * Add a static object of class *TCollection_AsciiString* with name *Reco_NewEntity* and initialize it with a string containing the STEP type.
+ * In constructor *WStepAP214_ReadWriteModule::RWStepAP214_ReadWriteModule()* add this object onto the list with the unique integer identifier of the new entity type.
+ * In function *RWStepAP214_ReadWriteModule::StepType()* add a new C++ case operator for this identifier.
+ * For complex types:
+ * In the method *RWStepAP214_ReadWriteModule::CaseStep()* add a code for recognition the new entity type returning its unique integer identifier.
+ * In the method *RWStepAP214_ReadWriteModule::IsComplex()* return True for this type.
+ * In the method *RWStepAP214_ReadWriteModule::ComplexType()* fill the list of subtypes composing this complex type.
+ * For both simple and complex types:
+ * In function *RWStepAP214_ReadWriteModule::ReadStep()* add a new C++ case operator for the new identifier and call the *RWStepxxx_RWNewEntity* class, method *ReadStep* to initialize the new class.
* Update file *RWStepAP214_GeneralModule.cxx*. Add new C++ case operators to functions *NewVoid()* and *FillSharedCase()*, and in the method *CategoryNumber()* add a line defining a category of the new type.
* Enhance the *STEPControl_ActorRead class* (methods *Recognize()* and *Transfer()*), or class(es) translating some entities, to translate the new entity into an OCCT shape.
~~~~~
Draw:> param [<parameter_name> [<value>]]
~~~~~
-Command param with no arguments gives a list of all parameters with their values. When the argument *parameter_name* is specified, information about this parameter is printed (current value and short description).
+Command *param* with no arguments gives a list of all parameters with their values. When the argument *parameter_name* is specified, information about this parameter is printed (current value and short description).
The third argument is used to set a new value of the given parameter. The result of the setting is printed immediately.
For reading a STEP file, the following parameters are defined (see above, <a href="#occt_step_6_2">the command *param*</a>):
-Description Name Values Meaning
-Precision for input entities read.precision.mode 0 or 1 If 0 (File), precision of the input STEP file will be used for the loaded shapes
-If 1 (Session), the following parameter will be used as the precision value
- read.precision.val real Value of precision (used if the previous parameter is 1)
-Surface curves read.surfacecurve.mode 0 or 3 Defines a preferable way of representing surface curves (2d or 3d representation).
-If 0, no preference.
-Maximal tolerance read.maxprecision.mode 0 or 1 If 1, maximum tolerance is used as a rigid limit
-If 0, maximum tolerance is used as a limit but can be exceeded by some algorithms
- read.maxprecision.val real Value of maximum precision
-
+| Description | Name | Values | Meaning |
+| :------------ | :---- | :------- | :------- |
+| Precision for input entities | read.precision.mode | 0 or 1 | If 0 (File), precision of the input STEP file will be used for the loaded shapes; If 1 (Session), the following parameter will be used as the precision value. |
+| | read.precision.val | real | Value of precision (used if the previous parameter is 1) |
+| Surface curves | read.surfacecurve.mode | 0 or 3 | Defines a preferable way of representing surface curves (2d or 3d representation). If 0, no preference. |
+| Maximal tolerance | read.maxprecision.mode | 0 or 1 | If 1, maximum tolerance is used as a rigid limit If 0, maximum tolerance is used as a limit but can be exceeded by some algorithms. |
+| | read.maxprecision.val | real | Value of maximum precision |
It is possible either only to load a STEP file into memory (i.e. fill the *InterfaceModel* with data from the file), or to read it (i.e. load and convert all entities to OCCT shapes).
Loading is done by the command
Here a dot can be used instead of a filename if the file is already loaded by xload or stepread.
The optional selection (see below for a description of selections) specifies a set of entities to be translated. If an asterisk `*' is given, all transferable roots are translated. If a selection is not given, the user is prompted to define a scope of transfer interactively:
-N Mode Description
-0 End Finish transfer and exit stepread
-1 root with rank 1 Transfer first root
-2 root by its rank Transfer root specified by its rank
-3 One entity Transfer entity with a number provided by the user
-4 Selection Transfer only entities contained in selection
+| N | Mode | Description |
+| :---- | :---- | :---- |
+| 0 | End | Finish transfer and exit stepread |
+| 1 | root with rank 1 | Transfer first root |
+| 2 | root by its rank | Transfer root specified by its rank |
+| 3 | One entity | Transfer entity with a number provided by the user |
+| 4 | Selection | Transfer only entities contained in selection |
* root is an entity in the STEP file which is not referenced by another entities
Second parameter of the stepread command defines the name of the loaded shape.
During the STEP translation, a map of correspondence between STEP entities and OCCT shapes is created.
-To get information on the result of translation of a given STEP entity use the command *Draw:> tpent \#*.
+To get information on the result of translation of a given STEP entity use the command @code Draw:> tpent #*.@endcode
+
+To create an OCCT shape, corresponding to a STEP entity, use the command @code Draw:> tpdraw #*. @endcode
-To create an OCCT shape, corresponding to a STEP entity, use the command *Draw:> tpdraw \#*.
-To get the number of a STEP entity, corresponding to an OCCT shape, use the command *Draw:> fromshape \<shape_name\>*.
+To get the number of a STEP entity, corresponding to an OCCT shape, use the command @code Draw:> fromshape <shape_name>. @endcode
-To clear the map of correspondences between STEP entities and OCCT shapes use the command *Draw:> tpclear*.
+To clear the map of correspondences between STEP entities and OCCT shapes use the command @code Draw:> tpclear. @endcode
@subsection occt_step_6_4 Analyzing the transferred data
+
The procedure of analysis of data import can be divided into two stages:
- 1.to check the file contents,
- 2.to estimate the translation results (conversion and validated ratios).
-
+ 1. to check the file contents,
+ 2. to estimate the translation results (conversion and validated ratios).
+
@subsubsection occt_step_6_4_1 Checking file contents
+
General statistics on the loaded data can be obtained by using the command
-Draw:> data \<symbol\>
+
+~~~~
+Draw:> data <symbol>
+~~~~
+
Information printed by this command depends on the symbol specified:
-* *g* - Prints the information contained in the header of the file;
-* *c* or *f* - Prints messages generated during the loading of the STEP file (when the procedure of the integrity of the loaded data check is performed) and the resulting statistics (f works only with fails while c with both fail and warning messages) ;
-* *t* - The same as *c* or *f*, with a list of failed or warned entities;
-* *m* or *l* - The same as *t* but also prints a status for each entity;
-* *e* - Lists all entities of the model with their numbers, types, validity status etc.
-* *R* - The same as e but lists only root entities
+* *g* - Prints the information contained in the header of the file;
+* *c* or *f* - Prints messages generated during the loading of the STEP file (when the procedure of the integrity of the loaded data check is performed) and the resulting statistics (f works only with fails while c with both fail and warning messages) ;
+* *t* - The same as *c* or *f*, with a list of failed or warned entities;
+* *m* or *l* - The same as *t* but also prints a status for each entity;
+* *e* - Lists all entities of the model with their numbers, types, validity status etc.
+* *R* - The same as e but lists only root entities
There is a set of special objects, which can be used to operate with a loaded model. They can be of the following types:
-* Selection Filters - allow selecting subsets of entities of the loaded model;
-* Counter - calculates some statistics on the model data.
+* Selection Filters - allow selecting subsets of entities of the loaded model;
+* Counter - calculates some statistics on the model data.
-A list of these objects defined in the current session can be printed in DRAW by command *Draw:> listitems*.
+A list of these objects defined in the current session can be printed in DRAW by command @code Draw:> listitems. @endcode
-Command *Draw:> givelist <selection_name>* prints a list of a subset of loaded entities defined by the selection argument:
+Command @code Draw:> givelist <selection_name> @endcode prints a list of a subset of loaded entities defined by the <i>\<selection\></i> argument:
-* *xst-model-all* all entities of the model;
-* *xst-model-roots* all roots;
-* *xst-pointed* (Interactively) pointed entities (not used in DRAW);
-* *xst-transferrable-all* all transferable (recognized) entities;
-* *xst-transferrable-roots* Transferable roots.
+* *xst-model-all* all entities of the model;
+* *xst-model-roots* all roots;
+* *xst-pointed* (Interactively) pointed entities (not used in DRAW);
+* *xst-transferrable-all* all transferable (recognized) entities;
+* *xst-transferrable-roots* Transferable roots.
The command *listtypes* gives a list of entity types, which were encountered in the last loaded file (with a number of STEP entities of each type).
Two commands are used to calculate statistics on the entities in the model:
~~~~~
-Draw:> count <counter> [\<selection\>]
-Draw:> listcount <counter> [\<selection\>]
+Draw:> count <counter> [<selection>]
+Draw:> listcount <counter> [<selection>]
~~~~~
The former only prints a count of entities while the latter also gives a list of them.
The optional selection argument, if specified, defines a subset of entities, which are to be taken into account. The first argument should be one of the currently defined counters:
-* *xst-types* - calculates how many entities of each OCCT type exist
+* *xst-types* - calculates how many entities of each OCCT type exist
* *step214-types* - calculates how many entities of each STEP type exist
Entities in the STEP file are numbered in the succeeding order. An entity can be identified either by its number or by its label. Label is the letter \# followed by the rank.
* *Draw:> elab \#* outputs a label for an entity with a known number.
* *Draw:> enum \#* prints a number for the entity with a given label.
-* *Draw:> entity \# <level_of_information>* outputs the contents of a STEP entity.
+* *Draw:> entity \# \<level_of_information\>* outputs the contents of a STEP entity.
* *Draw: estat \#* outputs the list of entities referenced by a given entity and the list of entities referencing to it.
* *Draw: dumpassembly* prints a STEP assembly as a tree.
@subsubsection occt_step_6_4_2 Estimating the results of reading STEP
All the following commands are available only after data is converted into OCCT shapes (i.e. after command 214read).
-Command *Draw:> tpstat [*|?]\<symbol\> [\<selection\>]* is provided to get all statistics on the last transfer, including a list of transferred entities with mapping from STEP to OCCT types, as well as fail and warning messages. The parameter symbol defines what information will be printed:
+Command *Draw:> tpstat [*|?]\<symbol\> [\<selection\>]* is provided to get all statistics on the last transfer, including a list of transferred entities with mapping from STEP to OCCT types, as well as fail and warning messages. The parameter <i>\<symbol\></i> defines what information will be printed:
-* *g* - General statistics (a list of results and messages)
-* *c* - Count of all warning and fail messages
-* *C* - List of all warning and fail messages
-* *f* - Count of all fail messages
-* *F* - List of all fail messages
-* *n* - List of all transferred roots
-* *s* - The same, with types of source entity and the type of result
-* *b* - The same, with messages
-* *t* - Count of roots for geometrical types
-* *r* - Count of roots for topological types
-* *l* - The same, with the type of the source entity
+* *g* - General statistics (a list of results and messages)
+* *c* - Count of all warning and fail messages
+* *C* - List of all warning and fail messages
+* *f* - Count of all fail messages
+* *F* - List of all fail messages
+* *n* - List of all transferred roots
+* *s* - The same, with types of source entity and the type of result
+* *b* - The same, with messages
+* *t* - Count of roots for geometrical types
+* *r* - Count of roots for topological types
+* *l* - The same, with the type of the source entity
The sign \* before parameters *n, s, b, t, r* makes it work on all entities (not only on roots).
The sign ? before *n, s, b, t* limits the scope of information to invalid entities.
-Optional argument \<selection\> can limit the action of the command to the selection, not to all entities.
+Optional argument <i>\<selection\></i> can limit the action of the command to the selection, not to all entities.
To get help, run this command without arguments.
To analyze the internal validity of the shape, use command *Draw:> checkbrep \<shape_name\> \<expurged_shape_name\>*. It checks shape geometry and topology for different cases of inconsistency, like self-intersecting wires or wrong orientation of trimming contours. If an error is found, it copies bad parts of the shape with the names <i>expurged_subshape_name _\#</i> and generates an appropriate message. If possible this command also tries to find STEP entities the OCCT shape was produced from.
<i>\<expurged_shape_name\></i> will contain the original shape without invalid subshapes.
-To get information on tolerances of the shape use command <i>Draw:> tolerance \<shape_name\> [\<min\> [\<max\>] [<symbol>]] </i>. It outputs maximum, average and minimum values of tolerances for each kind of subshapes having tolerances and for the whole shape in general.
+To get information on tolerances of the shape use command <i>Draw:> tolerance \<shape_name\> [\<min\> [\<max\>] [\<symbol\>]] </i>. It outputs maximum, average and minimum values of tolerances for each kind of subshapes having tolerances and for the whole shape in general.
When specifying min and max arguments this command saves shapes with tolerances in the range [min, max] with names shape_name_... and gives their total number.
-<i><Symbol></i> is used for specifying the kind of sub-shapes to analyze:
+<i>\<Symbol\></i> is used for specifying the kind of sub-shapes to analyze:
* *v* - for vertices,
* *e* - for edges,
* *f* - for faces,
@subsection occt_step_6_5 Writing a STEP file
For writing shapes to a STEP file, the following parameters are defined (see above, <a href="#occt_step_6_2">the command *param*</a>):
-
-Description Name Values Meaning
-Uncertainty for resulting entities Write.precision.mode -1, 0, 1 or 2 If -1 the uncertainty value is set to the minimal tolerance of CASCADE subshapes.
-If 0 the uncertainty value is set to the average tolerance of CASCADE subshapes.
-If 1 the uncertainty value is set to the maximal tolerance of CASCADE subshapes.
-If 2 the uncertainty value is set to write.precision.val
-Value of uncertainty Write.precision.val real Value of uncertainty (used if previous parameter is 2)
-
+| Description | Name | Values | Meaning |
+| :------------ | :----- | :------ | :------- |
+| Uncertainty for resulting entities | Write.precision.mode | -1, 0, 1 or 2 | If -1 the uncertainty value is set to the minimal tolerance of CASCADE subshapes. If 0 the uncertainty value is set to the average tolerance of CASCADE subshapes. If 1 the uncertainty value is set to the maximal tolerance of CASCADE subshapes. If 2 the uncertainty value is set to write.precision.val |
+| Value of uncertainty | Write.precision.val | real | Value of uncertainty (used if previous parameter is 2). |
Several shapes can be written in one file. To start writing a new file, enter command *Draw:> newmodel*.
Actually, command *newmodel* will clear the *InterfaceModel* to empty it, and the next command will convert the specified shape to STEP entities and add them to the *InterfaceModel*:
+
~~~~~
-Draw:> stepwrite <mode> \<shape_name\> [<file_name>]
+Draw:> stepwrite <mode> <shape_name> [<file_name>]
~~~~~
-The available modes are following:
- * *a* - as is;
- * *m* - manifold_solid_brep or brep_with_voids
- * *f* - faceted_brep
- * *w* - geometric_curve_set
- * *s* - shell_based_surface_model
-
+
+The following modes are available :
+ * *a* - as is - the mode is selected automatically depending on the type & geometry of the shape;
+ * *m* - *manifold_solid_brep* or *brep_with_voids*
+ * *f* - *faceted_brep*
+ * *w* - *geometric_curve_set*
+ * *s* - *shell_based_surface_model*
+
After a successful translation, if file_name parameter is not specified, the procedure asks you whether to write a STEP model in the file or not:
~~~~~
execution status : 1
projects / occt.git / blobdiff