Irradiance map baking

[X14Halo]

So I have a scene...and the only way that I can seem to get rid of this splotchy flicker is to bake out the irradiance map. The only thing is...I have moving objects in my scene. If I bake out say...every 20 frames of the irr map, what will happen to the moving objects? I assume that baking out every frame would be a bad idea since it would bake in the flicker I was seeing before. Any ideas that don't involve separating it into 2 scenes with the still objects in one and the moving objects in the other?

[vlado]

One way to do it is to bake animated irradiance maps in "Animation (prepass)" mode; then you can use the "Animation (rendering)" mode to cause V-Ray to load and interpolate between several irradiance maps, so that the splotches are reduced. How many frames will be blended depends on the "Interpolation frames" parameter of the irradiance map. If your camera is moving, it also helps to turn on the "Use camera path" option for the irradiance map (and the light cache, if you are using it).

You have to bake the maps for each frame though; right now it is not possible to skip frames with this method.

Best regards,
Vlado

[X14Halo]

Thanks Vlado. I did that, and I have interp frames to 3, but it made my rendertime like 3 times longer...any ways on speeding that up?

[jensl]

Frame interpolation at 3 means a total of 7 frames are analyzed (2*3 + 1). The default of 2 (total 5) may work better, as higher interp is also slower. You can usually get away with the 'medium animation' preset (or lower sometimes) if you have interp frames at 2. As you drop your GI settings you risk reintroducing flickering but you may be able to speed things up.

[vlado]

Thanks Vlado. I did that, and I have interp frames to 3, but it made my rendertime like 3 times longer...any ways on speeding that up?

Yep, one thing to do is to decrease the "interpolation samples" parameter. This value is multiplied by the number of loaded irradiance maps (to keep the degree of blurring the GI the same), however this means that with 3 interpolation frames (7 irradiance maps) and 20 interpolation samples, V-Ray now interpolates from 140 samples for each point, which may be way more than necessary.

Best regards,
Vlado