View Full Version : Animated GI step 1 render very slow

08-05-2016, 10:57 AM
Guys, I read some old threads and I found the Rebel Hill tutorial about animated GI on his channel, so I understand that there are some issue with animated cache.

If I get it right the animated cache bake regularly fast, but it renders slow because it doesn't store any shaders samples etc. I don't expect to be faster, but can it be like very very slow? I mean significantly slower than a regular F9 with same rpe and settings. I don't mean incrementally slow while animation progress, I mean that 1 frame takes probably 2x/3x time or more with animated cache active already baked.

In the scene the camera is always moving, and there are some animated objects like big boxes which the cover opens and shows inside (they need samples), and some other objects deformations. No animated lights (for now).

Bake GI with cache was set with preprocess to automatic, animation on, step 1, then for the F10 render preprocess set to locked and everything else not touched.
Radiosity take 1 sec (I expect that), but frame render is slow as hell.

08-12-2016, 01:33 PM
I can confirm... especially when rendering via network controller... 1st frame of any given range of starting frames would take 4x longer to render than subsequent frames on the same node... and this happened on all nodes starting up on their first frames.

I've since abandoned anim. cached GI in favor of brute forcing GI with non-interp. MC with VERY low ray count of 4 or 5 and letting adaptive AA take care of the noise (8 samples by 32 passes). Sure, render times doubled, so I just added a few more boxes already on the network to the controller (BNR 6). No more worrying about blotchiness, "loose"/under-defined corner/contact shading, flickering, other issues with pre-baking GI, and cache file size/number with their added network traffic.

08-12-2016, 04:01 PM
Yep Brute force it. Don't bother with cache. When you uncheck Interpolated LightWave rendering with GI is basically on a par with other render engines like Arnold. I don't mean to make the statement that performance/features and so on are the same. I just mean Arnold is a Monte Carlo brute for render solution. And Cycles, Renderman RIS etc are all using the similar basic solutions.