PDA

View Full Version : Ambient occlusion pass bug?



Slartibartfast
11-21-2014, 11:39 AM
Hi all!

It's probably been asked before, but :

I want to render out an occlusion pass by checking AO in image filter/composit buffer export. Now, I know I must have radiosity on for this to work, but when F10-rendering, only the first frame is an ambient occlusion image. The following frames is radiosity images. UNLESS I uncheck interpolated radiosity.

First of all - can anyone confirm this behaviour?
Second - Is there an EASY way of getting this to work? (Not involving extensive node setups, or changing surfaces on all objects for a special render session)

Thanks

Sensei
11-21-2014, 04:34 PM
Hi all!

It's probably been asked before, but :

I want to render out an occlusion pass by checking AO in image filter/composit buffer export. Now, I know I must have radiosity on for this to work, but when F10-rendering, only the first frame is an ambient occlusion image. The following frames is radiosity images. UNLESS I uncheck interpolated radiosity.

First of all - can anyone confirm this behaviour?
Second - Is there an EASY way of getting this to work?

AFAIK, no.

These things are somehow correlated. Because when GI is calculated there are send rays in the all directions to gather color. Ray-trace always is returning length of ray. And it's used for this pass, without doing anything else.. Secondary usage.



(Not involving extensive node setups, or changing surfaces on all objects for a special render session)

It's very easy when you have TrueArt's Global Materials http://globalmaterials.trueart.eu
Like you can see on this video tutorial
https://www.youtube.com/watch?v=i5Ti9kZRGI8
simply click Spread Global Materials,
and attach Occlusion node to Make Material then to global override.
Then press F10, and you have occlusion sequence.
No need to change and save objects, changing surfacing of all objects surfaces etc.
Literally 10 seconds of work.


You can even make a switch, camera that will render only occlusion
https://www.youtube.com/watch?v=qbrlhMfIgPU

Mr_Q
11-21-2014, 06:35 PM
If you want to avoid Third-Party shaders or editing in nodes there' s an easy way.

If you're trying to get an AO pass as part of a master render to save time, cool. If not, then just set all your surfaces to white. Set Ambient light to 100%, kill all other lights. Turn on Backdrop Mode radiosity and check on only Ambient Occlusion. Use Bumps is optional. Save out EXRs for maximum tweaking.

Slartibartfast
11-23-2014, 12:31 AM
If you're trying to get an AO pass as part of a master render to save time, cool

Yes, that's what I had in mind. Thank's for your help guys.