George Pantazopoulos wrote:
> 
> I think your questions are important, and I agree there needs to be more
> solid documention. I'll put some effort towards that.
> 
> The "Server" is a modified version of MegaPOV, to which I added a new thread
> to handle RPC requests.

So the server needs to run on all nodes supposed to participate in the 
distributed render.  I suppose when no render is running it is an idle 
program.

> 
> - Certain scene initializations such as parsing and photon shooting are only
> done once per scene session, and not for every tile.

But how do you transfer the data to the other nodes in a portable way 
then (and one that does not eat tons of network bandwidth)?

> pyxrsclient
> -----------
> 
> The client is a python script which conrols the servers and coordinates the
> parallel render. The servers are completely passive right now, so its up to
> the client to query the servers as to their status. pyxrsclient
> 
> The client was a lot of fun to develop mostly because I really love
> programming in Python. I was thrilled to find that Python comes with
> xmlrpclib, which I used right of the box to communicate with
> megapov_xrs_server.

I would suggest you sepearate the client from the GUI - a lot of people 
will probably prefer a command line interface (preferably syntax 
compatible with POV-Ray) or use it in a CGI script.

> 
> That's right, I can't guarantee renders free of tiling artifacts with
> MegaPOV XRS alone. However, what Jaime does is that he uses a normal
> version of megapov to create the radiosity data ahead of time. Then he
> modifies the scene with "always_sample off" and "load_file". Then he used
> Megapov XRS to render this scene, loading only the precalculated rad data
> and minimizing the calculation of new rad data while in parallel.

Well - the key word is 'minimize' - by design POV-Ray radiosity does 
always take new samples when necessary even in the final pass. 
Depending on scene and settings this can be a lot.

>> The newest radiosity patches in MegaPOV can help you minimize the
>> differences but without further changes (which will involve performance
>> loss) you won't get completely reproducible results in parallel renders
>> using radiosity.
>>
> 
> Which radiosity patches are those? Sounds interesting...

RADIOSITY_ADAPTIVE_RADIUS_PATCH and NEW_RADIOSITY_PRETRACE_PATCH.

Christoph

-- 
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 20 Aug. 2006)
MegaPOV with mechanics simulation: http://megapov.inetart.net/

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