[creasia]

Can anyone tell me how to get the matte/shadow effect in Studio that is similar to the standard 3dsmax matte/shadow material?

I am trying to project a realistic shadow onto a HDRI background by projecting the shadow of a car onto a plane, but I can't get the material right.

Thanks

Creasia

[tom]

[creasia]

Thanks Tom!

[bjorn.syse]

I think, that the manual does not mention that you have to render this kinda setup twice.

Once, with matte checked for the ground material to get the right Alpha-channel.

Twice, with shadow checked and matte unchecked on that same material.

Am I right?

Of course, it would be better if you could render both channels at the same time, since most of the times when using the shadow channel, you do want the matte, and corresponding alpha aswell..

regards,

- Björn

[Mr Whippy]

Hmmm, this is a bit flawed really.

Max's default Matte/shadow is used as a plane for reflections, so it picks up the camera's POV of the background image it is cast over, and then any reflective object in the scene see's that as what is there (ie, where the matte/shadow material is)

In Maxwell, what we get in the rgb output is a reflection of the raw HDRI reflection in a mirror over the matte/shadow for example, wheras in 3DS Max with basic scanline, the mirror material see's the patch of shadow/matte and reflects it as if it has taken on the HDRI image onto that plane.

Ie...

Maxwell:



Note how the reflection is of the pure HDRI background, with a shadow cast onto what is basically thin air.

3DS Scanline:



Note how the reflection is of the camera POV HDRI image applied to the plane I used to catch shadows. (no shadows as Max GI takes ages to look half decent, but shadows did render onto the Matte/shadow material perfectly well)


I think the above method for compositing is fine, but when you want HDRI scene integration we need a far better solution.

Dave

[Mr Whippy]

Also just tested to make 100% sure, the shadow photoshop multiply layer isn't visible in reflections in the composited object.

Ie, mirror ball on table, it won't see the shadows applied over the HDRI image, the only way to get shadows in the reflection appears to be to add a real BDSF layer, but then this isn't the background colour (cam POV HDRI underlay)...


Is it possible to just have a proper single Shadow/Matte material?

I remember a project a few years ago with Mental Ray where the Shadow/Matte didn't work and I had to spend about 5hrs total compositing images and doing loads of passes. I'd have used 3DS Scanline if not for the lack of decent glossy reflections...

Dave