none
Sounds loike a zbuffer problem. When at exactly the same elevation it doresn`t know which needs to be on top You could try adding zbias( 1 ) to the beginning of the drawing code and zbias( 0 ) after it. It is a while since I have done any code for CFS2 but I have a feeling I had to do this in the past
Great suggestion Martin, effectively there was a problem concerning the drawing priority.