VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Thu Aug 30 2001 - 21:49:52 CDT

Dear Troy,
  Sorry I haven't gotten to your email yet, I've been swamped
after returning from Siggraph and so on. Here are some answers
for you:
  1) To render the snapshots, you either need to have the images
     displayed on the VMD graphics window, or if you run VMD in text-mode,
     then you can often render much faster since it will skip rendering
     into the OpenGL window (since there isn't one :-)
     I wasn't sure from your question, if what you're _really_ asking
     is "can VMD do the snapshot from the OpenGL back buffer before
     it gets displayed on the screen and can be corrupted by mouse
     cursors and so on", then the answer is "no", at least not at the
     present time. I intend to rewrite a bunch of the "outer loop"
     code that manages the process of rendering every VMD frame, which
     will have two benefits:
       a) Snapshots can be done from the OpenGL back buffer before
          glSwapBuffers() is called and the user gets a chance to
          mess up the image. (This problem is actually quite system
          dependent as it turns out, which is why we didn't do it that
          way originally, we never saw the problem on the machines we
          originally wrote the code on. I became aware of it a while
          back but haven't had an opportunity to bang out the code to
          fix this yet, plus, see item b) below).
          
       b) After an outer-loop rewrite, VMD should be able to use
          more sophisticated rendering algorithms such as
          alpha-blended transparency, multi-pass rendering,
          multiple viewports in the graphics window,
          accumulation buffer antialiasing, motion blur,
          and other features.

  2) If you want to generate images that contain shadows, then
     my suggestion would be to use one of the supported ray tracing
     programs. Recent distributions of VMD have included my Tachyon
     ray tracer, so that one is now "built-in" so to speak. Raster3D,
     Rayshade, and POV-Ray are also good choices. All of these programs
     will generate several image formats, which can be converted to MPEG
     animations using free utilities found on the net (the VMD web page
     has some links to such information), and they are available for
     free. http://www.povray.org/ has a big software collection for
     conversion of images to movies.

Once again, sorry for the belated reply, let us know if you have other
questions.

Thanks,
  John Stone
  vmd_at_ks.uiuc.edu

On Thu, Aug 23, 2001 at 02:14:34PM -0400, Troy Wymore wrote:
>
> Hello VMD people,
>
> I am experimenting with a few things in making a movie of a MD trajectory
> and had a few questions.
>
> 1) To render all the snaphsots from a trajectory file, it appears that the
> image must be first displayed in the VMD console. Is there any
> possibility that the image could be rendered BEFORE the display is
> updated? Oh, I'm using the proc "make_trajectory_movie_files".
>
> 2) Any suggestions/reccomendations on which rendering software is best for
> making molecular snapshots and would also contain shadows? The resulting
> files would have to be able to be converted to an mpeg.
>
> Thanks so much,
>
> Troy Wymore
> Pittsburgh Supercomputing Center
>
> 

-- 
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