typedef int PK_SHELL_type_t;
This datatype indicates the type of a shell.
One of these values:
PK_SHELL_type_acorn_c shell has a single acorn vertex
PK_SHELL_type_wireframe_c shell has one or more wireframe edges
PK_SHELL_type_wireframe_free_c shell has no wireframe edges, but one
or more faces
PK_SHELL_type_mixed_c shell has both wireframe edges and faces