Optimising R14 GI (Full Animation)

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Old 09 September 2012   #1
Optimising R14 GI (Full Animation)

Hi - a bit more involved question this time, hope someone can help. I'm building a scene which is going to be rendered full-animation GI, with a rather tight deadline, so I'm on the lookout for techniques to build the prepass caches more quickly, if that's possible, and get the thing rendered without any nasty surprises - was wondering if anyone had any tips about this.

The animation is mainly camera animation, in that the camera moves around a room pausing (never stopping) at four or five stations, where fairly detailed animations take place.

I'm using the R14 radiosity maps, physical renderer + depth of field. IR+QMC (Full Animation). Current render time is around 4mins per HD frame.

Some of the tricks I've learned using VRay are to render the prepass with lower resolution, and skipping frames - is that possible/recommended in this case? So say my final result is 500 frames, full HD; can I render the prepass at 960x540 and skipping every other frame, then lock it and jump back to full res? Or will that cause problems/errors with the GI?

Last complication, the scene is going to be stereoscopic, so I'm hoping to render the prepass once then render the two eyes using the same ilum files - any pitfalls here?

The manual is pretty thorough in describing the functions of each aspect of the renderer, and the tips are good too, I'm running some simple test files now - but the I'm hoping there's some good experience out there as to how to best work with the new options.

Thanks for any advice - Chris
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Old 09 September 2012   #2
OK well I've got some bad news about this, and some good, and some more bad.

Bad news is that after 14 hours churning the pre-cache had finished it's first pass - of 12. So eta would be measured in weeks, which was unmanageable, so I stopped it there and started re-rendering IR+QMC (still image), with radiance maps on. Averaging around 4-5 mins per frame, total 36hrs or so - which is fine.

Good news is that the results look very stable so far, some slight flicker in areas with large, flat planes, but nothing to worry about.

Bad news - Cinema keeps crashing during the render, random intervals. I've sent the scene file off to Maxon.

I'm interested in the .gir file that is being written; will this be usable for a re-render, assuming nothing significant changes to the scene in the meantime? Would it be usable for the second eye of a stereo render?
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Old 09 September 2012   #3
OK - to end this pointless monologue, I've abandoned trying to make this work in Cinema's physical renderer, the crashes started to become more frequent the further into the scene I got. Shame, as the results weren't bad, fairly stable GI and good looking depth of field, but an unstable render is useless on a project like this, so it's off to VRay I go...
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Old 10 October 2012   #4
Nightmare. Thanks for posting your progress though.

I have to say i've already had a couple of crashes with the r14 renderer. We had a crash free couple of versions, I hope this will be resolved soon..
Old 10 October 2012   #5
Lots of render related crashing here too -- one thing I've discovered in the R14 is the SSS shader seems to be related to crashes, infinite pauses while rendering, and massively long render times if you have "Compute GI Contribution" enabled (the default).

"Direct" mode (on the Multiple Diffuse tab) also seems to be unusably slow.
Old 10 October 2012   #6
In my case is OpenGL's fault and how my card handles it :(
Old 10 October 2012   #7
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