Baking irradiance map (multiple frames) on multiple machines

[Fredrik Averpil]

Hi,

A while back it was discussed here to be able to generate an irradiance map for say frame 1, 10 and 20 on three different machines, resulting in three irradiance maps -- and then merging these maps into one using a standalone/commandline application (can't seem to find that old thread).

Are there any plans on such a thing?
Right now we are rendering for quite some while on a single machine to bake out every fifth (or so) frame for flythrough animations. This creates a little bit of a bottle neck as 20+ machines are idle, waiting for that single one to finish generating the irradiance map beforce commencing the final rendering on all machines (taking advantage of the irradiance map).

[tashko.zashev]

Hi,

Could you please share more details about this request?
What IR map mode you use for this setup?
Do you use a render manager to manage the render frames?

[Fredrik Averpil]

Hi Tashko,

Yes, we use a render manager. That way all artists can queue up their shots or projects and order them by priority before going home in the evening.

In this particular case we would queue up the same scene twice with different render settings:

Scene 1a - one machine: Irradiance map (primary engine) with mode set to "Incremental add to current map", Light cache (secondary engine). In this scene, the camera is flying through a static environment and writes to the IR map on every 10th frame or so. The final image is not rendered.
Scene 1b - all machines available: This scene is queued to render after scene 1a has finished. Irradiance map (primary engine) with mode set to "From File", secondary engine is set to 'None'. So it starts rendering the final image immediately.

Scene 1a becomes a bottle neck, as only one and the same machine can compute the irradiance map. Many times we leave one of these ones for rendering over night and when back in the morning it's not even half-way done generating the irradiance map. It would be fantastic to be able to render scene 1a using multiple machines and in conjunction with the render manager. This would mean all machines write to their own irradiance map file, I guess - and it would require us to merge all those irradiance map files into one big irradiance map file (maybe using a commandline app?) before rendering scene 1b, however this could be automated via some clever python scripting on the user side (our side). I understand this is not possible today.

I believe that right now we could resort to DR in order to render the irradiance map using multiple machines. But this would mean manually interfering with the render manager layer (pausing ongoing jobs and perhaps interrupt ongoing renders) in order to distribute the calculation of the irradiance map using DR slaves. Then whenever that is done, we would have to manually resume all ongoing jobs in the render manager -- thus require us to monitor this process rather than just queue it up in the render manager.

In a small studio like ours and with many parallell and tight deadlines, making the irradiance map bakable using multiple machines would make a big difference.

Let me know what you think and if I can provide you with more details.

[vlado]

You can use the imapviewer application to merge multiple irradiance maps, no problem.

Best regards,
Vlado

[Fredrik Averpil]

That's great, I now see all the commandline options for imapviewer.exe...!