Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] Bug Reporting => [C4D] Resolved Bugs => Topic started by: reublack on 2017-11-12, 01:11:37

Title: Alpha Channel doesn´t work
Post by: reublack on 2017-11-12, 01:11:37

Hey guys,

maybe someone could help me with an alpha channel problem (sorry if thit topic is already solved in another thread, link appreciated):
I created a scene with an obj, 2 lights and a studio-area (sphere, flat surface, e.g. as studio background). To render the scene I use an alpha tag in the Corona Multipass settings.
When i render everything without the studio-area, everything works well. I get a perfect alpha channel in the resulting psd-files.

The problem occurs, when i switch on the studio background. The alpha channel is white due to the fact that corona combines the obj and the studio. How can i select only the obj for the alpha tag in the multipass settings? What am I doing wrong? Any ideas?

Thanks for your help or any hint for a solution.

Best
B

Title: Re: Alpha Channel doesn´t work
Post by: maru on 2017-11-15, 12:10:00

Looks like there is an issue here indeed. Even when setting "alpha mode" in advanced material settings to "always black" it is still rendering as white. Moving to bugs.

Title: Re: Alpha Channel doesn´t work
Post by: houska on 2018-01-17, 19:12:02

Actually, the values for "black" and "white" were swapped. The fix should appear in one of the following builds

Title: Re: Alpha Channel doesn´t work
Post by: Nikola on 2018-01-30, 12:54:34

Hi Reublack,

it should be already fixed in the latest build https://forum.corona-renderer.com/index.php?topic=18711.msg119472#msg119472 (https://forum.corona-renderer.com/index.php?topic=18711.msg119472#msg119472), can you please confirm it?

Nikola

Title: Re: Alpha Channel doesn´t work
Post by: burnin on 2018-01-30, 16:26:17

seems fine on my side (w7, R18)

Title: Re: Alpha Channel doesn´t work
Post by: reublack on 2018-11-07, 20:11:50

Still have some issues with that :(. Any ideas?

Title: Re: Alpha Channel doesn´t work
Post by: burnin on 2018-11-07, 22:23:11

To get the solution, do describe your issues in detail.

Title: Re: Alpha Channel doesn´t work
Post by: Beanzvision on 2018-11-08, 10:40:19

Quote from: burnin on 2018-11-07, 22:23:11

To get the solution, do describe your issues in detail.

Couldn't have said it better myself! ;)

Title: Re: Alpha Channel doesn´t work
Post by: reublack on 2018-11-08, 19:57:38

;) ok thought that the stream tells enough. When I create scene, for example a background studio wall and an object, I cant geht an alpha pass out of the render.
Ich checked the alpha mask in the multipass settings. but the final mask is completly white. So, how can I get the studio wall ignored by the engine?
Can I assign a ID for the wall or the object?

Title: Re: Alpha Channel doesn´t work
Post by: Beanzvision on 2018-11-12, 13:46:07

Quote from: reublack on 2018-11-08, 19:57:38

;) ok thought that the stream tells enough. When I create scene, for example a background studio wall and an object, I cant geht an alpha pass out of the render.
Ich checked the alpha mask in the multipass settings. but the final mask is completly white. So, how can I get the studio wall ignored by the engine?
Can I assign a ID for the wall or the object?

Is this what you're after?

Title: Re: Alpha Channel doesn´t work
Post by: reublack on 2018-11-16, 23:28:42

Found out how it works. But thanks for your help guys anyway. In the new version of corona, it is very easy to handle it.