VRayMatte/ShadowMtl

[rmaytee]

Okay, I get that you can do this in a couple ways with render elements, but that is just another step that really irritates me. I wish you could just put a material on an object you want to mask other things in your scene (including the alpha channel).

Scanline and Mental Ray can do it just fine. Can't we at least make those materials compatible with Vray?

Especially for animations, it is extremely annoying to have to spend the extra time to add an alpha mask out of a separately rendered element to my video composition.

Now it's off my chest. And I can't be the only one who has this wish.

[instinct]

Right Click the objects -> VRayProperties -> matte object on, alpha to -1 and turn shadows on if you need them.

Can also be done on a material basis with the VRayMtlWrapper

Regards,
Thorsten

[percydaman]

vray would be a pretty cruddy renderer if it didn't have the capabilities of doing what your asking. Been able to do it for quite some time. Follow instincts post.

[rmaytee]

I agree. I have needed it MANY times over the years, and have relied on rendering a separate pass to make a mask for composting. Now I feel like an idiot knowing it is so simple.

Next time either of you make it to Salt Lake City, let me know, and I'll buy you a doughnut.

Thanks a billion.

[rmaytee]

Okay, so it still doesn't work the way I wanted it to.

I have a plane with Matte object turned on, and 0.0 alpha contribution. Works great in the render, I don't even have it shown on the alpha. the problem is, I want the things it is masking that are behind the object to be masked not only from the rendered image, but the alpha as well.

Instead I get an alpha that shows the objects beneath the plane. Can this be avoided? For instance, If I have an object growing from the ground, can I have only the object rendered above the ground and include the mask in the alpha?

[rmaytee]

Here is what I mean.

[rmaytee]

Nevermind, I re-read the first reply, and didn't notice he said -1 for the alpha contribution. I just had it to 0.

Sorry for being annoying.

[rmaytee]

Tell me this, Is there a way to have an object mask, but still see through the matte object?

For instance, I have some stationary tables in a room, but I want to have a mask cover the objects as if they were not there, then animate the matte object moving up so the tables gradually appear from the ground up without animating the tables--only the matte object.

Anyone know if there is a way to do this?

[percydaman]

afaik, this would have to be done in post, where you rendered a version with and without the tables.

[rmaytee]

I don't have a problem doing it in post. I just want to see it drawn in perspective, like a bird's view. The problem is, if I do it from a bird's view, my mask object also masks the tables.