(2019-08-11, 13:17)Hans de Lang Wrote: Hi All,Did you remember to invert the drawing order for rotations with negative determinants?
I'm trying to convert Ldraw parts to use in a Windows Presentation Foundation program, written with visual basic.
Drawing a 4-4disc.dat file for a stud.dat the triangles are CCW that's correct.
stud3.dat uses the same disc, so still CCW and so not visible from the bottom.
The disc has shift down de y axis. I imagen that when it flips so x,y become -x, -y it would be correct.
I use the buildin 4x4 Matrix3d and fill it like the LDraw explanation mentioned.
What am I missing?
Regards, Hans
(ie. Reverse the CCW drawing order if determinant(rotation) < 0)
If this is the issue, then I recommend adding this tip to the Culling/clipping page as everyone (including myself twice) have fallen into this.