(2019-08-11, 21:54)Hans de Lang Wrote: Excellent! That's the trick, now I can see both discs at the top and at the bottom.
Just so you know, full BFC (back face culling) support requires a lot more than just detecting when a matrix mirrors things. The BFC spec isn't super complicated to understand, but it isn't exactly trivial to implement. Also, some polygons in some parts are intended to be drawn on both sides. So to properly draw all LDraw parts, you have to support that also. (One easy way to do that if you can't have the rendering software draw both sides of polygons is to draw the polygons both ways.)