how to get the normal of a point on a on_mesh
You might start with this example:
Also, if a mesh has face normals, you can find in ON_Mesh::m_FN. If a mesh does not have face normal, you can compute them by call ON_Mesh::ComputeFaceNormals.
this example just deal with point.m_ci.m_type == ON_COMPONENT_INDEX::mesh_face
condition,but in fact ,the type also maybe other values,for example:ON_COMPONENT_INDEX::meshtop_edge,So I need know how to deal with all other
A topological edge does not have a normal. If you pick an edge, you will have decide which shared face you want to test.
thanks very much.
I will try using the closest vetex normal,because I find ComputerFaceNormal is too slow computer every time