VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Fri Apr 08 2005 - 14:38:30 CDT

Hi,

On Fri, Apr 08, 2005 at 11:17:52AM +0200, Suckjoon JUN wrote:
> Thank you both. Clearly my VMD and POV-Ray are not working together.
> Comments and more questions below:
>
> 1. For specifying the POV-Ray binary path, I simply browsed and
> clicked the POV-Ray program within the directory when VMD Movie Maker
> asked me. I guess I did something wrong then due to my ignorance.
> Which file is the POV-Ray binary? (POV-Ray 3.6 for MacOS X)

That's the problem, you need to give VMD the path to the binary
that's machine-runnable, i.e. that will accept command-line parameters.
I believe the file you selected was a MacOS X bundle, which doesn't
accept command line paramters and probably won't run in batch mode.

> 2. Yes, I do want to make high(er)-quality movies. I have about 100 ~
> 1000 frames of trajectories from my simulations. When I see them frame
> by frame, VMD does render beautifully. Naively, I was thinking that
> VMD simply saves each frame with *that* quality and combines them into
> a movie file. Apparently, Movie Maker seems to "think" more,
> interpolrating between frames creating blurred low-resolution image
> sequences.

Actually, it's neither situation :-)
VMD _does_ save the frames exactly as they are on the screen, but
this is impractical to use for a movie, as the storage requirements
for the movie would be several gigabytes in many cases. The movie maker
itself doesn't actually "blur" anything, this is a side-effect of conversion
to a compressed MPEG-1 stream. MPEG-1 was designed to produce
VHS-resolution images, and anything that's beyond that will either
a) look VERY bad when it is compressed, or will b) have to be downsampled
to meet the bitrate and resolution requirements of MPEG-1
properly downsampled and compressed

If you want to make movies that have much less compression and a much
higher peak resolution, you'll have to use a commercial compression
program for MPEG-2, or one of the proprietary movie codecs like Quicktime,
AVI, etc. You can still use the movie maker to generate the raw image
frames, but then you have to do the compression for yourself with other
software.

> 2'. I do have QuickTime Pro, although I am not quite experienced with
> it. Is it possible to save high-quality individual frames using VMD in
> 2 above as a image sequence (what is the file type? JPEG? GIF? Or
> something else?) and then automatically read them in using QuickTime
> Pro? Is there instruction for this somewhere on the web?

Yes, the movie maker saves full-resolution / full-quality image frames
when it runs. You just need to uncheck this checkbox:
  Movie Settings->Delete Image Files

Once that's unchecked, make your movie as usual, it'll do what it normally
does, but at the end, you'll have all of the full-resolution image files
in PPM format. You can load those into QuickTime Pro or other tools
to compress them into a movie for yourself.

  John Stone
  vmd_at_ks.uiuc.edu

> On Apr 7, 2005 10:31 PM, John Stone <johns_at_ks.uiuc.edu> wrote:
> >
> > Hi,
> > When you specify the path to POV-Ray, The movie maker plugin
> > needs the path to the actual POV-Ray binary, not just the
> > MacOS X POV-Ray bundle/directory. The errors you're getting
> > about renaming files are because POV-Ray failed to run and thus
> > there are no image files to convert. The output you're going to
> > get from POV-Ray should be nearly identical to what you're getting
> > from VMD itself or Tachyon, so if you're not happy with the results,
> > perhaps we should find out why before you spend time on something
> > that's going to give you almost identical results. What is it that
> > you're not happy with? Do you want to make a higher-resolution movie?
> > If you want to make a high-quality high-resolution movie, then you may
> > need to use a different movie compression tool, using the movie plugin
> > just for the purpose of creating the initial movie frames, but doing the
> > movie compression yourself with Quicktime, or whatever you feel would
> > give you better results.
> >
> > John Stone
> > vmd_at_ks.uiuc.edu
> >
> > On Thu, Apr 07, 2005 at 10:00:51PM +0200, Suckjoon JUN wrote:
> > > Hello,
> > >
> > > I have a problem with Movie Maker plugin. I am using VMD 1.8.3 on my
> > > Powerbook (OS 10.3.8). I am trying to make a movie with renderer
> > > option POV-Ray, which I downloaded version 3.6 from
> > > http://www.povray.org/download/.
> > >
> > > In the 2nd stage, I get the error message
> > >
> > > "Could not locate povray
> > > Description: POV-Ray Ray Tracer
> > > Would you like to specify its path?"
> > >
> > > So I say 'yes' and specify its path (the file 'POV-Ray Mac 3.6'). Then
> > > VMD progresses to 4th stage, and I get another error message:
> > >
> > > "Error: error renaming "/'my working
> > > directory'/blahblahblah.0000.ppm": no such file or directory"
> > >
> > > So I go to my working directory and see what happend. VMD Movie Make
> > > has created bunch of .dat files but no .ppm files.
> > >
> > > What is wrong? I would very much appreciate any help from VMD users --
> > > I need to urgently create movies for supplementary materials of my
> > > rearch articles and upcoming talk in two weeks.
> > >
> > > Thank you,
> > > Suckjoon JUN
> > >
> > > PS. I have no problems when I use the first two internal renderers
> > > 'Snapshot' or 'Internal Tachyons', but the quality is not very
> > > satisfactory.
> >
> > --
> > 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
> > 

-- 
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