Irradiance - Use Camera path

[snivlem]

Hi,

Perhaps I'm most likely wrong, but I was under the impression that "Use Camera Path" would mean that there is only pass calculated for a flythrough...ie a static scene with only a moving camera?

you can turn the Use camera path option on, and render just one single frame - this will produce information for the entire camera path.

I've got a scene here with this option turned on, but Irradiance Map, during batch, is still calculating every frame.

[2013/Feb/8|20:16:26] V-Ray: Prepass 1 of 2...
[2013/Feb/8|20:16:26] V-Ray: Prepass 2 of 2...
[2013/Feb/8|20:16:26] V-Ray: Rendering image...
[2013/Feb/8|20:16:26] V-Ray: (Estimated time remaining: 0h 0m 2.0s): 10 % completed
[2013/Feb/8|20:16:27] V-Ray: (Estimated time remaining: 0h 0m 2.0s): 25 % completed
[2013/Feb/8|20:16:27] V-Ray: (Estimated time remaining: 0h 0m 1.7s): 35 % completed

Then the next frame:

[2013/Feb/8|20:16:29] V-Ray: Prepass 1 of 2...
[2013/Feb/8|20:16:29] V-Ray: Prepass 2 of 2...
[2013/Feb/8|20:16:29] V-Ray: Rendering image...
[2013/Feb/8|20:16:30] V-Ray: (Estimated time remaining: 0h 0m 3.4s): 11 % completed
[2013/Feb/8|20:16:30] V-Ray: (Estimated time remaining: 0h 0m 2.3s): 22 % completed
[2013/Feb/8|20:16:30] V-Ray: (Estimated time remaining: 0h 0m 1.8s): 32 % completed

etc..

As a result the GI flickers and rendering time is increased.

Maya 2013.5x64 and happens with the latest build as well.

I am sure that I've gotten this to work before so that during a batch, V-Ray calculates Irradiance ONLY on the first frame then for the rest of the render it automatically freezes itself and V-Ray reads the cached Irradiance Map?

Should this be the case?

[vlado]

This is correct, yes - the "Use camera path" option only fixes the samples that are shot out of the camera for the irradiance map. But it still recalculates the map for each frame.

Best regards,
Vlado

[snivlem]

Thank you for confirming Vlado.

For some reason I had it in my head that this mode worked exactly the same as the "Fly-through" mode of the Light Cache. (ie generated once for an entire animation).

Is there a reason why "Use Camera Path" has to recalculate for each frame and not once at the beginning of an animation like "Fly-through" mode?

[vlado]

Yes, there is - you might have moving objects which means the map has to be recalculated for each frame.

For walkthroughs, I'd still recommend to precalculate the irradiance map with "incremental add" mode.

Best regards,
Vlado