Dealing with the visitor for clip(mesh, plane) with clipVolume=true

[stla]

Hello,

When we do clip(mesh, plane) with clipVolume=true and we use a visitor, there are two meshes involved in the visitor: the mesh, and the piece of the plane which will close the clipped mesh.

That could be embarassing. Image I have that in the visitor:

  void after_subface_created(face_descriptor fnew, const EMesh3 & tm) {
    (*FACEMAP)[fnew] = *ofaceindex;
  }

This function will be executed when the mesh tm is the piece of the plane, and this is not what I want.

The solution I found is to assign a dummy property map "f:dummy" to the mesh in order to be able to identify it, and then I modified the above code as follows:

  void after_subface_created(face_descriptor fnew, const EMesh3 & tm) {
    if(tm.property_map<face_descriptor, std::size_t>("f:dummy").second){ 
      (*FACEMAP)[fnew] = *ofaceindex;
    }
  }

Is there a better solution?

And what could be an usage of the visitor to do something with the piece of plane? I cannot imagine any example.