0031552: Bad performance of intersection of cylindrical surfaces Adjusting parameters of algorithm depending on axes and parameters of cylinders is added in order to reduce computation time Test case added: tests/lowalgos/intss/bug31552 tests/perf/modalg/bug26310_1: test case corrected according to current state of algorithm

0030670: Modeling Algorithms - Performance improvement of Boolean Operations algorithm The following improvements have been made in Boolean operations algorithm: 1. Added possibility to update FaceInfo structure for many faces at once which helps to avoid nested loops. 2. Improve Point-Face classification procedure by caching the FaceExplorer for a face.

0030435: Improving performance of Approx_ComputeCLine 1. Approx_ComputeCLine.gxx, Approx_FitAndDivide.hxx, Approx_FitAndDivide2d.hxx, BRepFill_ComputeCLine.hxx It is base modification, which allows improve performance of approximation with help of Approx_ComputeCLine. The main idea of improvement is using degree selection by inverse order - from maxdegree to mindegree. If tolerance for maxdegree is not reached, there is no sense to make approximation for current number of knots with lower degree, it is necessary to cut parametric interval. 2. ProjLib_ComputeApprox, ProjLib_ComputeApproxOnPolarSurface, ProjLib_ComputeApproxOnPolarSurface, ProjLib_ProjectOnPlane It is additional modification of methods using Approx_ComputeCLine. Mainly, modifications concern to more optimal choosing parameters for approximation algorithm. 3. BRepCheck_Face Small improvement of method Intersect(...), which intersects two wires on face. 4. BRepTopAdaptor_FClass2d Impovement of treatment infinitely narrow faces. 5. ChFi3d/ChFi3d_Builder_6.cxx Small improvement, which forbids extension of singular boundary of surface. It was TODO problem in tests/bugs/modalg_7/bug27711_3 6. IntTools_EdgeEdge.cxx Improvement of performance for cases of searching common parts between line and analytical curve 7. GeomliteTest_CurveCommands.cxx Adding Draw command fitcurve. This command is analog of approxcurve, but uses Approx_FitAndDivide algorithm. Mainly to have direct draw command for testing Approx_ComputeCLine. 8. Extrema_ExtElC.cxx Treatment of case "infinite solutions" for extrema line-ellipse 9. Modification of some tests according to new behavior of algorithm. 10. tests/perf/moddata/bug30435 Test for new improved algorithm. 11. Implementation QAcommand OCC30435 in QABugs_20.cxx used in test bug30435

0030489: Modeling Algorithms - BRepBuilderAPI_GTransform hangs Approx_ComputeCLine.gxx - criterium to stop interval cutting is increased. ProjLib_ProjectedCurve.cxx - fix regression for bugs modalg_5 bug25886 Other tests are modified according to current state of algorithm

0026106: BRepMesh - revision of data model Removed tight connections between data structures, auxiliary tools and algorithms in order to create extensible solution, easy for maintenance and improvements; Code is separated on several functional units responsible for specific operation for the sake of simplification of debugging and readability; Introduced new data structures enabling possibility to manipulate discrete model of particular entity (edge, wire, face) in order to perform computations locally instead of processing an entire model. The workflow of updated component can be divided on six parts: * Creation of model data structure: source TopoDS_Shape passed to algorithm is analyzed and exploded on faces and edges. For each topological entity corresponding reflection is created in data model. Note that underlying algorithms use data model as input and access it via common interface which allows user to create custom data model with necessary dependencies between particular entities; * Discretize edges 3D & 2D curves: 3D curve as well as associated set of 2D curves of each model edge is discretized in order to create coherent skeleton used as a base in faces meshing process. In case if some edge of source shape already contains polygonal data which suites specified parameters, it is extracted from shape and stored to the model as is. Each edge is processed separately, adjacency is not taken into account; * Heal discrete model: source TopoDS_Shape can contain problems, such as open-wire or self-intersections, introduced during design, exchange or modification of model. In addition, some problems like self-intersections can be introduced by roughly discretized edges. This stage is responsible for analysis of discrete model in order to detect and repair faced problems or refuse model’s part for further processing in case if problem cannot be solved; * Preprocess discrete model: defines actions specific for implemented approach to be performed before meshing of faces. By default, iterates over model faces and checks consistency of existing triangulations. Cleans topological faces and its adjacent edges from polygonal data in case of inconsistency or marks face of discrete model as not required for computation; * Discretize faces: represents core part performing mesh generation for particular face based on 2D discrete data related to processing face. Caches polygonal data associated with face’s edges in data model for further processing and stores generated mesh to TopoDS_Face; * Postprocess discrete model: defines actions specific for implemented approach to be performed after meshing of faces. By default, stores polygonal data obtained on previous stage to TopoDS_Edge objects of source model. Component is now spread over IMeshData, IMeshTools, BRepMeshData and BRepMesh units. <!break> 1. Extend "tricheck" DRAW-command in order to find degenerated triangles. 2. Class BRepMesh_FastDiscret::Parameters has been declared as deprecated. 3. NURBS range splitter: do not split intervals without necessity. Intervals are split only in case if it is impossible to compute normals directly on intervals. 4. Default value of IMeshTools_Parameters::MinSize has been changed. New value is equal to 0.1*Deflection. 5. Correction of test scripts: 1) perf mesh bug27119: requested deflection is increased from 1e-6 to 1e-5 to keep reasonable performance (but still reproducing original issue) 2) bugs mesh bug26692_1, 2: make snapshot of triangulation instead of wireframe (irrelevant) Correction in upgrade guide.

0029911: Porting to Debian80-64 : Regressions in Foundation Classes Test for handles is updated according to behavior expected from modern compilers. Performance test perf ncollection A1 is updated (valid range extended) according to measurements made on Debian 8 with GCC 4.9 and on Ubuntu 16.04 with CLang 3.8 and 6.0 and GCC 4.7, 4.9, and 5.0.

0029967: Draw Harness - command bounding has annoying syntax Bnd_OBB constructor from Bnd_Box is fixed for VOID input. DRAW command bounding command is adjusted: - Support of old syntax 'bounding shape'is restored. - Exception on VOID bounding box is avoided. - Arguments are handled in case-insensitive way. - Options -s, -perfmeter, and ability to set result as first argument are removed as redundant. - Help is moved to command definition. Separate command OCC29311 is added (in QADraw) to do the same as option -perfmeter did; tests are updated.

0029830: STEPCAFControl_Reader poor performance - quadratic dependence Various performance improvements in STEP read/write algorithms: - Search for the label of a shape or component shape is improved using map mechanism instead of brute force iteration. - Invariant FindEntities() is moved out of the loop in the method getStyledItem in STEPCAFControl/STEPCAFControl_Writer.cxx. - A pointer to the end of binders chain is added in Transfer_Binder class to speed up adding a binder to the chain. - Small fixes are added to eliminate excess copying of handles, calls of handle DownCasts and so on. Stack overflow is removed during destruction of STEP model with long chains of Transfer_Binder. It is possible to use the Draw commands ReadStep and WriteStep to read/write from the session without accessing the disk file (use '.' for the file name). Performance test cases for STEP reading/writing have been added.

0028747: Incorrect result of the section operation after edge refinement Implementation of the method for simplification of the result of Boolean Operation on the API level. The method BRepAlgoAPI_BuilderAlgo::SimplifyResult has been added, so the derived classes such as BooleanOpeation and Splitter can also use this method. The result shape simplification should be called after the operation is done. The simplification is performed by the means of ShapeUpgrade_UnifySameDomain algorithm. Draw command "bsimplify" has been added to control the simplification options. Documentation for new functionality and draw commands controlling the options of Boolean operations. Test cases for the new functionality. Side-effect change: The algorithms in Boolean component have been changed to use the BRepTools_History as a History tool. Now it became possible to disable the collection of shapes modifications during Boolean Operations, which may be useful for performance sake (in draw the option is controlled by *setfillhistory* command). Draw command "unifysamedom" has been changed to accept the angular tolerance in degrees instead of radians.

0029712: Extrema algorithm raises exception 1. Extrema algorithm calls Curve-surface intersector. This intersector returns flag about infinite solution (in spite of extrema's returning not-parallel status correctly - axes of considered cylinder and circle are not parallel). In this case, attempt of obtaining number of intersection points leads to exception. So, the fix adds check of infinite solution after the intersection algorithm. 2. The methods IsDone(), IsParallel(), NbExt(), SquareDistance() and Points() (of Extrema_* classes) have been corrected to make them consistent to the documentation. 3. Revision of some Extrema_* classes has been made in order to avoid places with uninitialized variables. 4. Currently Extrema does not store any points in case when the arguments are parallel. It stores the distance only. 5. Some cases on Extrema-algo have been moved from "fclasses"-group to "modalg"-group.