[Chimera-users] Faster raytracing

Thomas Goddard goddard at cgl.ucsf.edu
Thu Jul 9 17:24:22 PDT 2009

Berni explains below his procedure for using povray 3.7 beta with 
Chimera to raytrace faster using multiple cores on Windows.


-------- Original Message --------
Subject: Re: [Chimera-users] Faster raytracing
From: Bernhard Pätzold
To: Thomas Goddard <goddard at cgl.ucsf.edu>
Date: 6/28/09 8:57 AM

Hi Tom

Thanks for your help. I actually managed to get the raytracing running 
on multiple processors, although I will consider your advice for the 
future and use more the Chimera inbuild rendering features. As even with 
multiple processors and serious calculation power raytracing takes just 
way too long.

However in case someone want to do the same I will quickly describe how 
i got it running under Windows. It might be substantially easier under 
Linux but my system is currently seriously impaired so that I need to 
fix that first. Just changing the input file in Chimaera did for some 
reason not work and I always got the message that it can't find the 
file. It worked fine under Linux until it crashed again, so I think that 
might be the best way there.

So here is the windows way:

1. Install the PovRay 3.7 beta release
2. Rename the file povray.exe in the ../Chimera/bin folder to povrayold.exe
3. Copy the file pvengine.exe from PovRay to the Chimera/bin folder
4. Rename pvengine.exe to povray.exe
5. Start PovRay and change in the menu under "render" => "On Completion" 
the Value from do nothing to "Exit on completion"
6. Now you can generate raytraced images as usual just the actual 
raytracing process will run in paralell on all cores.

Note: X3d2pov will still only run on one processor.

I had once a strange error that could be easily fixed changing the 
directory of my script to a different one.



-------- Original Message --------
Subject: Re: [Chimera-users] Faster raytracing
From: Thomas Goddard <goddard at cgl.ucsf.edu>
To: Bernhard Pätzold
Date: 6/25/09 5:18 PM

> Hi Berni,
>   Elaine's suggestion to change the path to the povray executable in 
> Favorites / Preferences, category POV-Ray may work if you don't need 
> some extra command arguments to tell it to use multiple cores.
>    A couple changes to parameters in the POV-Ray preferences pane can 
> also speed up render frames very dramatically (3x or more).  First 
> change "Antialias threshold" from 0.3 to 1.5.  That gave a 3x speed-up 
> with almost no noticable change in edges (it removes jagged edges). 
> Also try reducing quality from 9 to 4 or 5.  See the documentation for 
> what you would be missing by doing that:
> http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/preferences.html#POV-Ray%20Options
>    Also if you are using the Chimera 1.3 production release you might 
> want to get a Chimera 1.4 daily build where the transparency handling by 
> pov-ray now matches what is on-screen much better.
>    Also if you get tonight's daily build or more recent you will not get 
> the pov-ray progress dialogs popping up at each frame.  Instead the halt 
> button will be on the status line.
>    Finally, you might consider some comments on the Chimera mailing list 
> from this week which suggest that you can often make a better image 
> without using pov-ray.  Better lighting and silhouette edges are 
> available in Chimera without pov-ray -- and the main feature of pov-ray, 
> shadows, can be more distracting than illuminating
> http://www.cgl.ucsf.edu/pipermail/chimera-users/2009-June/004030.html
> 	Tom
> -------- Original Message --------
> Subject: [Chimera-users] Faster raytracing
> From: Bernhard Pätzold
> To: chimera-users at cgl.ucsf.edu
> Date: 6/25/09 2:26 PM
>> Hello
>> I love Chimera and the only little bummer to me are the long rendering times for raytraced movies. I managed to get the PovRay version 3.7 which uses multiple cores running on our server. However now I am stuck and here comes my question. 
>> Is there away how I can get Chimera to use the newer Version of PovRay? Or can I somehow change my script so that I get only the .pov and .ini files for all the frames while the actual raytracing is skipped and I can do it subsequently with the newer Version?
>> Currently the whole things has to happen on a windows system, but I hope that I'll get my ubuntu version soon up and running again, so hints and advices for both options are welcome.
>> Thanks a lot in advance
>> Berni
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