ForceVolMesh.halfface_vertex_ancestor
- ForceVolMesh.halfface_vertex_ancestor(halfface, vertex)
 Return the vertex before the specified vertex in a specific face.
- Parameters
 halfface (int) – The identifier of the halfface.
vertex (int) – The identifier of the vertex.
- Returns
 int – The identifier of the vertex before the given vertex in the face cycle.
- Raises
 ValueError – If the vertex is not part of the face.