Open CASCADE, the 3D modelling kernel
3D modeling & numerical simulation

Search the Forums
See All Topics
Open CASCADEShowroomGet it!Developer CornerSupport and ProductsAbout us
Technical overview
Areas of use
Shape factory
Shape gallery
What's new
System requirements
Download Center
Public license
Getting started
Open Source community
Training and e-learning
A-la Carte Support
Value-added software
Complementary Components
Customer Corner
Company Profile
Marketing Materials
Contact Us
Home / Developer Corner / Forums / Usage issues / Single-edge face triangulation fails

Single-edge face triangulation fails

Single-edge face triangulation fails
Wayne Christopher 2011/07/27 23:48
I have a TopoDS_Edge which is a circle, and has the same vertex on both ends.

I put this edge into a wire, using BRepBuilderAPI_MakeWire, and then create a face from the wire using BRepBuilderAPI_MakeFace. This succeeds (i.e. MakeFace.IsDone() is true).

When I try to use BRep_Tool::Triangulation however, it fails.

The funny thing is, when I read this same circular face from a STEP file, created externally, the triangulation is fine.

Any thoughts on what's going on? Should I be using a different mechanism to create the face such as GeomPlate_BuildPlateSurface?
spam killer 2011/07/28 07:40
This works for me (OCCT 6.5.1, VS2010, x86):

          // face
          gp_Pnt center(0,0,0);
          gp_Circ circ(gp_Ax2(center, gp::DZ()), 100.0);
          TopoDS_Edge edge = BRepBuilderAPI_MakeEdge(circ);
          BRepBuilderAPI_MakeWire mkWire;
          TopoDS_Face face = BRepBuilderAPI_MakeFace(mkWire.Wire());

          // triangulation
          BRep_Builder builder;
          TopoDS_Compound compound;
          TopLoc_Location L; //= TopLoc_Location();
          Handle(Poly_Triangulation) triangulation = BRep_Tool::Triangulation(face, L);

          // check result
          if (!triangulation.IsNull())
               int nbTriangles = triangulation->NbTriangles();
               const Poly_Array1OfTriangle & triangles = triangulation->Triangles();
               const TColgp_Array1OfPnt & nodes = triangulation->Nodes();
               for (int i = 1; i <= nbTriangles; i++)
                    Poly_Triangle triangle = triangles(i);

                    Standard_Integer node1,node2,node3;
                    triangle.Get(node1, node2, node3);

                    gp_Pnt v1 = nodes(node1);
                    gp_Pnt v2 = nodes(node2);
                    gp_Pnt v3 = nodes(node3);

                    TopoDS_Edge e1 = BRepBuilderAPI_MakeEdge(v1,v2);
                    TopoDS_Edge e2 = BRepBuilderAPI_MakeEdge(v2,v3);
                    TopoDS_Edge e3 = BRepBuilderAPI_MakeEdge(v3,v1);
                    TopoDS_Wire w = BRepBuilderAPI_MakeWire(e1, e2, e3);
                    TopoDS_Face fTriangle = BRepBuilderAPI_MakeFace(w);

                    builder.Add(compound, fTriangle);
               if (nbTriangles > 0)
                    Handle_AIS_Shape aisShape = new AIS_Shape(compound);
lanhan 2012/07/04 07:28
     TopLoc_Location L1;     
Latest news
  • New features to enhance the development process
  • Open CASCADE Technology 6.7.1 is available for download!
  • Open CASCADE Technology 6.7.0 is available for download!

  • © OPEN CASCADE 2000 - 2014  |  Search  |  Contacts   |  Site map