When drawing complex shape data with OpenGL, you might see the error
message "This renderer cannot currently handle concave shapes, or shapes
with holes."

This is a matter of taking the time to override the addPolygonTriangles()
method in PGraphics3D to instead use the OpenGL tessellator. The
tessellator is already use for rendering font data with textMode(SHAPE) so
it's a matter of a straightforward of adapting that code for broader use.
Not technically impossible, but requires an afternoon's work to implement.