Sometimes when the end caps pointed strait up (z axis) their faces would become inverted. It seems like the code tried to rely on a certain vertex order to always happen. However this edge case did manage to produce an order that would produce inverted cap faces. So now I introduce a normal check instead so we can be certain that the face will have the normal direction we want. Reviewed By: Jacques Lucke Differential Revision: http://developer.blender.org/D4138