Isotropix Forums

Volumetric rendering AOVs scatter and lightgroups

General Discussion about Isotropix and CG related topics

Volumetric rendering AOVs scatter and lightgroups

Unread postby fmonster » Tue May 03, 2022 10:22 am

Hello,
I'm testing some volumetric rendering with clouds currently and I have an issue.
I need to render Aovs lightgroups, as well as emission (from the VDB temperature and scatter) and other things.

When I set up LPEs for this and I comp the rendered Aovs, I don't have exactly the same thing as the beauty.

Here are the LPEs sent to the AOVs :
Lightgroups beauty (1,2,3,4 etc) : C.*['1']
Emission : the original "PBR emission" found in the originals AOVs from Clarisse under volume.

Do I miss something in the AOVs ?
Thank you !
F.
Attachments
VDB_AOVS_test2.png
Precomp AOVs
VDB_AOVS_test1.png
Beauty
fmonster
 
Posts: 20
Joined: Mon Nov 01, 2021 12:50 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby sam » Tue May 03, 2022 4:41 pm

Hi,
Do you have any emissive material? Because your expression capture everything including emission for each light (so it is added multiple times when you recomp). You need to have emission separately from the lights beauty expressions
Sam Assadian
Isotropix
CEO/Founder
User avatar
sam
 
Posts: 1827
Joined: Fri Jan 25, 2013 11:33 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby fmonster » Tue May 03, 2022 5:51 pm

Thanks a lot for your answer Sam !

Yes I have Emission in the volume shader, drove by temperature and scatter from Houdini output.
I thought the expression was just keeping the light and not the Emission, but it's weird, if Emission was included in each lightgroup, it should simply brighten the cloud at the end of the comp, compare to the beauty. For now the beauty is brighten than the recomp.
Here are the preview of the different AOVs. It doesn't seem to me that the emission is included in the lightgroups ? What do you think ?
I don't know, it seems that I miss some indirect rays somewhere in the lightgroups or something else no ? Or the Emission AOV seem maybe a little too weak ? Maybe the original AOV "Emission" I peak is not a good one for a volumetric scenario ?
Attachments
VDB_AOVS_test_AOVs.jpg
Emission
fmonster
 
Posts: 20
Joined: Mon Nov 01, 2021 12:50 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby sam » Tue May 03, 2022 7:05 pm

because you are getting the indirect illumination of the emission in each light I guess
Sam Assadian
Isotropix
CEO/Founder
User avatar
sam
 
Posts: 1827
Joined: Fri Jan 25, 2013 11:33 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby fmonster » Tue May 03, 2022 8:56 pm

Hi Sam, thanks again for your reply.

And is there a way to grab the indirect illum or the emission for each lightgroup in an AOV ? In term of volumetrics ?
fmonster
 
Posts: 20
Joined: Mon Nov 01, 2021 12:50 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby fmonster » Tue May 10, 2022 3:58 pm

A little up, if anyone would know the reason of this difference, and know the solution : )
fmonster
 
Posts: 20
Joined: Mon Nov 01, 2021 12:50 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby sam » Tue May 10, 2022 4:42 pm

Did you check the documentation?
https://clarissewiki.com/5.0/lpes-useful-examples.html

The solution is right there
Sam Assadian
Isotropix
CEO/Founder
User avatar
sam
 
Posts: 1827
Joined: Fri Jan 25, 2013 11:33 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby fmonster » Tue May 10, 2022 5:19 pm

Yes, I went through this,

I may be wrong, but I used this expression :
Lightgroups beauty (1,2,3,4 etc) : C.*['Light1']
And another AOV "pbr_emission" native from clarisse.
It's possible I didn't catch something. In the native Aov "pbr_emission", I should have the direct and indirect ? As well as for the lightgroup expression above, it should keep direct and indirect ?

I think reading your answer I really missed something. I will dig further.

Thank you Sam.
F.
fmonster
 
Posts: 20
Joined: Mon Nov 01, 2021 12:50 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby sam » Tue May 10, 2022 10:49 pm

The expression is the correct one. As stated in the doc, that's the beauty per light excluding emission.
Regarding emission, try to use: C.*O (which includes direct + indirect)
Sam Assadian
Isotropix
CEO/Founder
User avatar
sam
 
Posts: 1827
Joined: Fri Jan 25, 2013 11:33 pm

Re: Volumetric rendering AOVs scatter and lightgroups

Unread postby fmonster » Wed May 11, 2022 10:26 am

Ok I will try by adding this aov then.
Thank you Sam
fmonster
 
Posts: 20
Joined: Mon Nov 01, 2021 12:50 pm


Return to General Discussion