Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: kotos on 2021-12-01, 19:09:16

Title: Volume light
Post by: kotos on 2021-12-01, 19:09:16

Hi all :)
How to make volume light like in this sample which i made in Octane?
Trying, but cant copy this light effect in Corona. Any help?

www.imgur.com/a/AMHx16v (http://www.imgur.com/a/AMHx16v)

Title: Re: Volume light
Post by: TomG on 2021-12-01, 19:15:25

Lights do not have volumes in Corona - like the real world, it is the media that the light passes through that causes this effect :) So instead it is a Volume Material applied to geometry that represents the atmosphere/air that does it. Our YouTube has tutorials:

Hope that helps!

Title: Re: Volume light
Post by: kotos on 2021-12-01, 19:39:25

Thank you for answer, so i watched it. Add Volume to cube which is fog enviroment. Still not works. ANy link to c4d  how it works? Still dont get it
https://imgur.com/a/W3T4mIb (https://imgur.com/a/W3T4mIb)

https://imgur.com/a/Yq2WhxS (https://imgur.com/a/Yq2WhxS)

Title: Re: Volume light
Post by: TomG on 2021-12-01, 20:18:24

It's very dependent on scene scale, as different scales will require different Absorption amounts - there's no "one size fits all" so impossible to say which settings to use. Absorption is usually best close to but not quite white.

Most importantly here your Scattering is black - which means the volume won't scatter any light (which is what is happening in a volumetric set up - light is traveling in one direction, hits a dust particle in the air for example, and gets bounced to travel in another direction). With Absorption only and black scattering you are just creating a dark fog that will darken everything without scattering any light.

To make the rays stand out more, it's best to have Single Bounce Only checked, otherwise light may bounce multiple times giving the whole volume a brighter glow (which means the first bounce will stand out less since it will be surrounded by more of a glow).

Title: Re: Volume light
Post by: kotos on 2021-12-01, 21:21:13

I Found solution. Ambient Oclusion as Scattering. But with this Corona renderer slows extremly.

https://imgur.com/a/Ja1GDJj (https://imgur.com/a/Ja1GDJj)

https://imgur.com/a/M0kmQLu (https://imgur.com/a/M0kmQLu)

Title: Re: Volume light
Post by: Nejc Kilar on 2021-12-02, 09:04:16

Quote from: kotos on 2021-12-01, 21:21:13

I Found solution. Ambient Oclusion as Scattering. But with this Corona renderer slows extremly.

https://imgur.com/a/Ja1GDJj (https://imgur.com/a/Ja1GDJj)

https://imgur.com/a/M0kmQLu (https://imgur.com/a/M0kmQLu)

I'm not quite sure why you've used the AO shader in there but I would pretty much second what Tom has said here - scattering is key. Once you have some absorption AND some scattering (so just assign a color to it, can be white too) you'll get that effect from the reference you posted. It also helps if your light has some directionality to it.

Title: Re: Volume light
Post by: Beanzvision on 2021-12-02, 13:02:21

Hi there, please see our helpdesk guide for this, as others have mentioned, there shouldn't be a need for AO here.
https://support.corona-renderer.com/hc/en-us/articles/4402435052561-How-to-make-god-rays-with-Corona-Renderer-in-Cinema-4D