VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Mon Aug 16 2010 - 12:54:37 CDT

Ian,
  TachyonInternal uses a Tachyon that is compiled directly into VMD.
Rather than emitting the scene as a human readable text file,
it is rendered directly from memory, saving a significant amount
of runtime that would otherwise be spent on disk I/O. The main case
where you would want to run the external Tachyon renderer is when you
want to re-render the same scene (e.g. at higher resolution) or you
want to otherwise edit or tweak the scene file.
Unless you're running an older version of VMD on a Windows machine,
Tachyon will indeed use all of your CPU cores, but only for the
rendering part of the runtime. The Tachyon builds used in the
Windows version of VMD 1.8.7 do run on all CPU cores, so if you're
not seeing them get pegged, then you may just be rendering scenes
that spend most of the time in the pre- or post-processing, with little
rendering time, as only the rendering phase is currently accelerated
by multi-core CPUS.

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu

On Mon, Aug 16, 2010 at 01:03:30PM -0400, Ian Stokes-Rees wrote:
>
>
> On 8/16/10 12:08 PM, John Stone wrote:
> > The issue is that the Tachyon code isn't compiled into the shared
> > library version of VMD. To get that to work, we would need to teach
> > the shared library builds of VMD to link against a shared library
> > version of Tachyon, then it should work ok. I'll have to look at this
> > and get back to you.
>
> This is a somewhat related question: what is the difference between
> "Tachyon" and "Tachyon Internal"? Which should I pick for my
> rendering? As best I can tell, neither of them make use of the 4 (or 8)
> cores on the machine I'm running VMD on.
>
> Thanks
>
> Ian 

-- 
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