Invisible object but visible in VRayRenderID?

[Streetwise]

Try as I might, I can't figure out how to make an object invisible, but yet still have it leave a VRayRenderID instance. Even after turning off "Visible to Camera" and messing with the other render controls yields nothing. For instance, I want to put a small plane on a carpeted floor so that I have the option to change the exposure of the plane area in post, to make the carpet appear to look inlayed with a darker shade. Doesn't seem to be working for me though. Maybe another way to do this?

[crazy homeless guy]

Post picture of what you are trying to accomplish.. it will help explain the thought.

[Streetwise]

Here's an example. In this particular example, I made a plane under the desk, raised it to .1 on the z-axis, and added the same carpet material. Then in post, I took the VRayRenderID channel for it and adjusted the exposure. Looks okay, except that you can tell it's slightly raised making it look like a rug on a rug. The thought would be to make it invisible so that I can still grab the VrayRenderID and tweak just that area. Just looking for a quick and dirty way to do it without having to create a separate material, etc.

[tsvetan.geshev]

Hello,

As a workaround you can go to Object Properties of the plane and make the Visibility to 0.001. This way, you will not see the geometry in the final render, but it will be included in the render element.
I test this on very simple scene, so let us know if you find some issues.

[crazy homeless guy]

The visibility solution sounds like it would add render time. Can you just make it not cast shadows?

[tsvetan.geshev]

Yes, you can turn off shadows and visible to GI , but I think, there is no faster way to do this.

[Morbid Angel]

typically if the object is not present in primary buffer it wont be possible to put it in a custom user buffer. Though I wonder if such render element could be made? otherwise we typically render such things as a separate pass.

[Streetwise]

Hello,

As a workaround you can go to Object Properties of the plane and make the Visibility to 0.001. This way, you will not see the geometry in the final render, but it will be included in the render element.
I test this on very simple scene, so let us know if you find some issues.

This worked perfectly and did exactly what I wanted. It didn't seem to have any impact to render times. Thanks.

[Svetlozar Draganov]

Glad to hear that this workaround is useful for you.