V-Ray - primary visibility off but still have object appear in MultiMatte?

[dwarfvader]

Hi,

 

I posted this elsewhere but did not get an answer so far. Maybe here somebody will know an answer. So, apologies for the cut/paste.

 

Maybe V-Ray matte or Primary Visibility are not the answer. So far I tried Primary Visibility, Hold Out, and V-Ray Matte options but none seem to give the desired effect. See pictures attached.

 

Let's say I want to render a scene with a tree. It's a dense poly tree, it takes a while. I am rendering these passes:

diffuse

rawLight

multiMatte

 

- The tree needs to be invisible in diffuse, but I need to see the objects in front of- and behind it (V-Ray Matte cuts to background, so I cannot see what is behind the tree).

- Also visible in rawLight, but still cast shadows, and still see the rawLight of the stuff behind it (same as above).

So far this is achievable with Primary Visibility off.

 

But I also need it to appear in multiMatte. With Primary Visibility off, it disappears from the multimatte/ID, which is fair enough. V-Ray matte works, but as above it doesn't work with the rest of the scene. Is there a way to make this work?

 

So far I am using render layers to separate the scene - one layer for everything (beauty, diffuse, rawLight...), and one layer just for the matte.

This works but doubles my render time (V-Ray will sample my geometry even with a surfaceShader material).

 

The scene itself goes from 1 minute to 2 minutes in render time per frame, but over 200 frames it adds up. I need to render it a lot back and forth to test lighting setups, so it kinda matters. But anyway it just seems like such an obvious thing I want to know if it's possible.

 

Thanks

 

Example (instead of tree please meet mr cube):

 

 

 

[Francisco Penaloza]

Have you tried combining passes in post, I don't think you can achieve this in a single pass but if you combine your matte pass with an object select for instance, then you can hold the mask of the hidden object.

 

You can combine using Wire color, Mat ID, Object ID, VRay Id or any other ID pass.

This is typical workflow to adjust in post, if you can't get a mat of something specific, you build it from other mats or transforming what you have.

[byoungsooahn]

Hi,

Try wire color on render elements. It used to works for me.

[dwarfvader]

Hi,

Try wire color on render elements. It used to works for me.

 

Have you tried combining passes in post, I don't think you can achieve this in a single pass but if you combine your matte pass with an object select for instance, then you can hold the mask of the hidden object.

 

You can combine using Wire color, Mat ID, Object ID, VRay Id or any other ID pass.

This is typical workflow to adjust in post, if you can't get a mat of something specific, you build it from other mats or transforming what you have.

 

Thanks both of you,

 

Unfortunately V-Ray for Maya doesn't seem to have the Wire Color aov. It seems to be a Max-only thing, at least no documentation on it for maya and not in the aov list.

 

Francisco, I have tried so far but nothing exactly comes to mind how to recombine this image. Do you have any specific suggestions? Any V-Ray render element so far hides the object if it is hidden otherwise. Any tips appreciated.

I also tried duplicating an object, keeping Visibility on but hiding it, didn't work, just to put it out there.