VMD-L Mailing List

From: Robin L Hayes (robin.hayes_at_nyu.edu)
Date: Fri Aug 10 2007 - 17:22:37 CDT

Hello,

I am having the same problem as Amadeu on May 05, 2006. Namely, I am attempting to use vmd 1.8.5 combined with POV-Ray 3.6.1c on Windows to generate a movie of a CPMD trajectory of a molecular crystal. When I omit HBonds, each frame renders correctly. However, when I include HBonds, about 25% of the frames generate the following error in POV-Ray:

Parse Error: Degenerate cylinder, base point = apex point.

I can switch which frames have the problem by resetting the view and re-applying the transformations (rotate y by 90, rotate z by 90, scale by 1.75), but I can't eliminate the problem entirely. Presumably, the former changes which numbers are small. The previous thread gave the solution, "apply transformation matrix tricks to the exported geometry so POV-Ray doesn't have problems with very small numbers". It's unclear to me which tricks I should apply or whether it is possible to apply those tricks before the POV-Ray files are written. Thanks.

Robin