VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Wed Aug 14 2002 - 11:30:51 CDT

Hi Marc,
  Which version of VMD are you running presently? We have made a number
of significant changes to the scene export modules since VMD 1.7.x which
may address some of the points you mentioned below. Generally speaking,
all of the renderers tend to have antialiasing and various other features,
but VMD doesn't necessarily enable them by default. You mentioned that
things look very shiny, this is easily modified by changing the material
properties you've selected in VMD itself. The geometry displayed by VMD
is tesselated at a fairly minimal level by default, in order to make it easier
for people with slow computers/video boards to view large structures.
One side effect of this is that the graphics you see (by default) in VMD
tend to look much less shiny than what a ray traced version of the same
scene looks like. VMD 1.8 has also fixed several limitations and bugs
in the scene export features so that using Tachyon, one can now get
images which are almost identical to what is seen in the VMD OpenGL window,
but with higher quality rendering. I still have some work to do to make
the same improvements to the other renderer export codes, but I hope to
get this done before VMD 1.8 is finished. The main thing I have left to
improve in the Tachyon scene export is the way it renders transparency.

If you'd like to try out the new code, let me know, I would be happy to provide
you with new binaries to test. If you can give us feedback then that would
help us improve the scene export features for the final version of VMD 1.8.

BTW, for the version of VMD you probably have now, you can enable
antialiasing in Tachyon with the -aasamples command line flag.

I'll see about that syntax error problem you mentioned for the ART
ray tracer. Let me know if you have more questions.

Thanks!
  John Stone
  vmd_at_ks.uiuc.edu

On Wed, Aug 14, 2002 at 05:01:13PM +0100, Marc Baaden wrote:
>
> Hi,
>
> I was trying to run a little cross-comparison on the rendering
> packages supported by VMD. After finally getting most of them
> to work, I ran into problems with some of the packages,
>
> - Radiance: produces just a black picture .. any hints ?
> - Rayshade: is incredily slow .. but I guess that's just the way
> it is ?
> - Art: just a note, the comment lines starting with // produce
> syntax errors
>
>
> and have some questions about ..
>
> - Tachyon: the output seems to lack anti-aliasing and is very
> shiny. Can this easily be improved ? Also transparency
> is not very nice.
>
> - Povray: output seems a bit dark and also very shiny.
>
> - RenderMan: I use BMRT, are there other (non-commercial) options ?
> Has anybody combined vmd RIB files with custom shaders ?
>
> I would also be interested in any user-contributed kind of tweaks/
> improvements/modifications of the renderings (like eg customized
> header files) if anybody wants to share them.
>
> Best wishes,
>
> Marc Baaden
>
> --
> Dr. Marc Baaden - Laboratory of Molecular Biophysics, Oxford University
> mailto:baaden_at_smplinux.de - ICQ# 11466242 - http://www.marc-baaden.de
> FAX/Voice +49 697912 39550 - Tel: +44 1865 275380 or +33 609 843217
> 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu                 Phone: 217-244-3349              
  WWW: http://www.ks.uiuc.edu/~johns/      Fax: 217-244-6078