The triangular mesh is converted to TopoDS_Shape

[hazidh]

Hello, I have a triangle mesh vertex coordinates and vertex index of a model, how to create a TopoDS_Shape？Looking forward to your reply！Thanks

[dpasukhi]

OCCT do not provide functionality to convert mesh to BRep. That is complex task.
You can use the class to create polygon-base faces: BRepBuilderAPI_MakeShapeOnMesh
After that you can unifysamedomain to merge planar areas

To create shape (not BRep) you can use the next code:

BRep_Builder aBuilder.
TopoDS_Face aFace;
Handle(Poly_Triangulation) aTriangulation = ...; // need to have not null
aBuilder.MakeFace(aFace, aTriangulation);

[hazidh]

OCCT do not provide functionality to convert mesh to BRep. That is complex task. You can use the class to create polygon-base faces: BRepBuilderAPI_MakeShapeOnMesh After that you can unifysamedomain to merge planar areas

To create shape (not BRep) you can use the next code:

BRep_Builder aBuilder.
TopoDS_Face aFace;
Handle(Poly_Triangulation) aTriangulation = ...; // need to have not null
aBuilder.MakeFace(aFace, aTriangulation);

Thank you very much for your reply. Then what I want to ask is if I only have the triangle mesh data of the model, can the TopoDS_Shape constructed by the method you mentioned be used for projection and Boolean operation such as HLRBRep_Algo and BRepAlgoAPI_Fuse?

[dpasukhi]

No, the the most parts of OCCT algos works only with geometry,not mesh.

[hazidh]

Thank you for your reply. Is there no way to convert mesh into TopoDS_Shape and perform projection operation in OCCT?

[dpasukhi]

What is a projection?
HLR (hidden line removing)? It can be done with mesh originally. Also, you can convert to polygon-base and then unify. Converting each triangle to face will be performance downing.