PDA

View Full Version : Final Gather render issue



adrian
09-07-2016, 02:28 AM
I was recently rendering a scene using final gather but due to the time it was taking I stopped the render at frame 118 (out of 150) and re-started it from 119 the next day. Despite nothing changing in the scene (ie shading/lighting samples, light settings etc) the animation from 119-150 had darker shadows than from frames 1-118. Due to this the render is useless and I'll need to do the whole thing from scratch again. :thumbsdow

I was rendering each frame out to JPG and using the radiosity cache option as only the camera in the scene was moving. As I say, all the scene settings were exactly the same.

Has anyone else ever encountered this?

Sensei
09-08-2016, 10:51 AM
If new GI samples are added to cache each frame, it's inevitable.

To fight with it, there is needed baking GI cache, in anim mode,
and then LOCKING it.. and save scene.
So it won't be modified any further.
(after doing all these steps, try rendering frame in the middle, save output, quit everything, reload, and try rendering same frame again in fresh instance, to check whether it looks similar. Use Photoshop with subtract mode, 1st image in one layer, 2nd in second layer)

However some nodes have their own interpolation caches in Advanced tabs..

There are nodes, and resources which randomize things all the time,
and their f.e. noise each time is slightly different.

Thomas Leitner
09-09-2016, 02:54 AM
...I was rendering each frame out to JPG and using the radiosity cache option as only the camera in the scene was moving....


...To fight with it, there is needed baking GI cache, in anim mode,
and then LOCKING it.. and save scene....

Hi,
if only the camera in the scene is moving itīs advisable to use radiosity cache without "Animation" checked.
What to do: Bake some radiosity frames of your animation (with "Bake Radiosity Frame". For some scenes itīs usefull to automate the baking with "Bake Radiosity Scene" and some frame step settings). It depends on your scene: the more it changes the more frames you will need (you should roughly cover all seen surfaces of your scene). Lock the cache (as Sensei mentioned). Render.

ciao
Thomas

adrian
09-09-2016, 04:53 AM
Thanks for the tips guys, I will give that a go.