On Sep 24, 2010, at 3:49 PM, Friedman, Simon H. wrote:

Hey Eric, Here is a mockup of the cover. I have a question for you: If you look at the helix, there are some very funky shadows that ended up very blocky. Other shadows are completely smooth. The helix was rendered in pov using default everything (from Chimera). Any insights into the blocky shadows? They are on one strand only!

Hi Simon, That's because right now the ribbons are being represented by a bunch of triangles. One of the things on Greg's to-do list is to have them represented by NURBS curves, which POV-ray would be able to shadow smoothly, but that hasn't happened yet. For now, you can mitigate the blockiness by upping the subdivision quality to 5 or higher. Control of the subdivision quality is in the "Effects" tab of the side view. --Eric