backface culling

Of course, backface culling can not be used with degenerate and unclosed volumes.

Backface culling is inverted and the back-facing triangles are drawn in black.

This is known as backface culling.

To prevent this the object must be set as double-sided (i.e. no backface culling is done) or have separate inside surfaces.

It is possible to eliminate unneeded data from going through the rendering pipeline to cut out extraneous work (called view volume clipping and backface culling).

For example, if an object is solid and has ordered vertices, an implementation may turn on backface culling and turn off two-sided lighting.