VMD-L Mailing List

From: Nicolas SAPAY (nicolas.sapay_at_cermav.cnrs.fr)
Date: Wed Aug 19 2009 - 04:59:45 CDT

Thanks for the answer

> On Wed, 2009-08-19 at 09:22 +0200, Nicolas SAPAY wrote:
>> Hello,
>
> salut nicolas,
>
>> I'm trying to render a scene with Tachyon. When I use the following
>> command:
>> render Tachyon ./img/molecule_0.dat
>>
>> VMD correctly generates the .dat file, but the tachyon command is not
>> executed and no picture is rendered. To render the picture, I have to
>
> this is the expected behavior.
>
>> execute the command manually:
>> exec /home/software/vmd-1.8.7/lib/tachyon_LINUXAMD64 -aasamples 12
>> -auto_skylight 0.8 ./img/molecule_0.dat -format TARGA -o
>> ./img/molecule_0.dat.tga
>
> right. however, with the new materials and display settings
> that control all these flags from within VMD, there is little
> reason to call the tachyon externally, but rather enable the
> proper flags and use the TachyonInternal renderer.

I was persuaded it was not possible to control the ambient occlusion
within VMD, but I realize there is a new flag available with the render
command:
  aosamples method samples

I'm not sure to understand exactly what its purpose is. Does it control
the amount of light coming from the ambient lightning?

>
>> I can perfectly live with that, but I'd like to understand where the
>> problem comes from. Note that if I execute something like that:
>> exec [render options Tachyon]
>>
>> the exec fails with a "file not found" error.
>
> there is no problem. you should have a closer look at the
> user's guide. also, the "file not found" error makes perfect
> sense, as you are not correctly grokking tcl syntax. everything
> in square brackets is evaluated as a tcl command using the
> return value of the command text within the square brackets.
> so whatever return value the render command produces, the
> exec command tries to run as executable, which does not exist.
>

My mistake, I didn't check the TCL manual first.

Nicolas

> cheers,
> axel.
>
>> Cheers,
>> Nicolas
>>
> --
> Dr. Axel Kohlmeyer akohlmey_at_gmail.com
> Research Associate Professor
> Institute for Computational Molecular Science
> College of Science and Technology
> Temple University, Philadelphia PA, USA.
>
> 

-- 
[ Nicolas Sapay - Post-Doctoral Fellow ]
CERMAV - www.cermav.cnrs.fr
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