Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] General Discussion => Topic started by: ficdogg on 2019-08-26, 11:35:37

Title: material ID mask from a material with opacity stacked
Post by: ficdogg on 2019-08-26, 11:35:37

I have a project where we have some text and graphics on a product and would like to get a mask out for fine-tuning the color in post.
I made a quick test scene as an example of the issue I'm running in to.
I have a cube with a white glossy material on it and the graphics as a darker material with opacity stacked on top of it. In multipass I have a mask with material ID set up.
Applied over another material the mask doesn't render, applied just on a plane, it shows up. Is this a bug or am I missing something?
I have hundreds of these renders coming up as well as dozen or so animations, so ideally I'd set this up as a multipass output rather than a separate render.

Title: Re: material ID mask from a material with opacity stacked
Post by: brankonovakovic on 2019-09-05, 10:00:41

Why you dot try UV Mapping ?

Title: Re: material ID mask from a material with opacity stacked
Post by: ficdogg on 2019-09-05, 11:43:22

What do UV maps have to do with material ID masks?

Title: Re: material ID mask from a material with opacity stacked
Post by: daveclive on 2019-09-06, 03:58:54

Hey, not sure what the poster means by using UV mapping either, don't think they understand the issue or how to solve it

You could try using render selected only feature in corona.
Perhaps separate or clone the label and only apply the text you want to isolate to that and then can slot that into render selected only and that way will keep the alphas in place and you will get an isolated label/text.

hope that makes sense

Title: Re: material ID mask from a material with opacity stacked
Post by: Beanzvision on 2019-09-06, 11:47:07

Hi ficdogg, can you send us that sample scene? https://corona-renderer.com/upload :)

Title: Re: material ID mask from a material with opacity stacked
Post by: Nejc Kilar on 2019-09-06, 12:29:40

Yeah so this is an interesting question :) I suppose the poster wants to know whether he can apply Material A and then Material B (with an opacity map, for example dirt) on top  on the same object and get out proper masks for both materials.

Apparently it only works if it is applied on a plane but as soon as its applied on another shape it doesn't work.

Title: Re: material ID mask from a material with opacity stacked
Post by: ficdogg on 2019-09-06, 16:53:20

@daveclive
That could work, but the idea was to get the masks out when doing the main render, not a separate render. I have a way of quickly setting up a render where only the text/graphics show up, but even with less than 10 seconds per frame, it quickly adds up for long animations.

@nkilar
That's exactly what I'm trying to achieve.

Attached is a test scene.

Title: Re: material ID mask from a material with opacity stacked
Post by: peteer on 2020-08-14, 02:00:36

Hi, did you find a way to fix this? I have the same problem

Title: Re: material ID mask from a material with opacity stacked
Post by: ficdogg on 2020-08-14, 20:12:19

Unfortunately no, I still have to render it separately if I need it.