Contents, API Reference, Interfaces, iFaceVertexBuilder, startMesh
Informs the builder that calls to addVertex() and so on will follow, for a new mesh.
This method will be called before any other methods, for the first mesh being built,
as well as before other methods for any additional meshes built after that.
Note that vertex and face indices will then start from zero, once again,
and indices cannot be used to refer to vertices or faces in previously built meshes.