J. L. Rose <jro### [at] spamBgonenbnetnbca> wrote:
: I was trying to make this image using a bent-up bicubic patch, and
: noticed some odd bright and dark spots on it.

  From the povray documentation:

As POV-Ray processes the Bezier patch it makes a test of the current piece
of the patch to see if it is flat enough to just pretend it is a rectangle.
The statement that controls this test is flatness. Typical flatness values
range from 0 to 1 (the lower the slower).
...
There are both advantages and disadvantages to using a non-zero flatness.
...
The biggest disadvantage is that if POV-Ray stops subdividing at a particular
level on one part of the patch and at a different level on an adjacent part
of the patch there is the potential for cracking. This is typically visible
as spots within the patch where you can see through. How bad this appears
depends very highly on the angle at which you are viewing the patch.

-- 
                                                           - Warp. -

Post a reply to this message