OSTexo,

Thank you for talking more about your process. I don't understand what you're using MarkCurveStart for. I would have thought that 2 abutting faces always share an edge and so the intersections of the shade lines and the edge could be used to transfer line spacing between faces. I guess I haven't run into the problem that MarkCurveStart solves, but I'm glad you brought it up so that I'll know about it when I need it.