Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: lmikkelb on 2015-04-27, 16:35:20

Title: ShadowCatcher lights not visible in alpha
Post by: lmikkelb on 2015-04-27, 16:35:20

Hey!
Does anyone know how to get the lights included in the alpha  with ShadowCatcherMtl, when rendering with  alpha mode: For composting ? or is it not supported yet?

Title: Re: ShadowCatcher lights not visible in alpha
Post by: maru on 2015-04-27, 17:09:07

There is "shadowcatcher illuminator" option for lights, but I can't get it visible in alpha.

Title: Re: ShadowCatcher lights not visible in alpha
Post by: lmikkelb on 2015-04-27, 18:28:37

Yes . look`s like its not incuded in this alpha mode. Is this  a bug or is it  just not supported yet? 

Title: Re: ShadowCatcher lights not visible in alpha
Post by: Ludvik Koutny on 2015-04-28, 09:10:01

you need to set alpha mode to "for compositing"

Title: Re: ShadowCatcher lights not visible in alpha
Post by: maru on 2015-04-28, 11:13:47

That's what I did but still it doesn't seem to work. Direct light is not visible on the shadowcatcher, only shadows and GI. 

Title: Re: ShadowCatcher lights not visible in alpha
Post by: lmikkelb on 2015-04-28, 11:39:28

yes alpha mode"for compositing" not rendering lights that hit the shadowcatcher material.

Title: Re: ShadowCatcher lights not visible in alpha
Post by: Ludvik Koutny on 2015-06-09, 11:49:19

Logged on mantis: https://corona-renderer.com/bugs/view.php?id=1078

Archiving to resolved.

Title: Re: ShadowCatcher lights not visible in alpha
Post by: Ondra on 2015-10-11, 22:32:24

That is by design. When using the compositing mode, you should place the beauty pass over the background without multiplying it with alpha (assume it has premultipled alpha). The alpha only modulates the background, but it should not modulate the beauty pass to get a correct result. If there was solid alpha below illumination from illuminators, that would make light from one source (scene illuminator) occlude light from other sources (background photo plate) - that is not how light works.