ALPHA MATT ?

[Adam H. Stewart]

I know this question was answered before but I cannot find the thread. I want to recreate the Alpha Matt functions available in Scanline with Max Material Alpha/Matt and I can't seem to do so.
I know that there is a Matt alpha section in the V-ray properties but it seems not to be working. I am using 1.09.
The Alpha Matt material crashes v-ray and making the object invisible to camera using the max properties doesn't help the situation.
I have some picture frames I want to cast shadow but I don't want to render.

Thanks as always

Adam H. Stewart

[bottom89]

1. pick vray material wrapper in a material slot
2. for base material, choose the regular vray material
3. check "matte surface"
4. change alpha contribution to 0.0

[egz]

If you want the matted object to be masked out in the alpha channel, you need to set alpha contribution to -1.0

[Adam H. Stewart]

Eureka !!

Thanks Guys the -1 in the alpha contribution did the exactly what I was trying to do. This has saved me literally hours if not days of work - before I was doing a seperate version of the scene using the Scanline renderer or FR.

Thanks again.

Adam H. Stewart

[Infrared digital]

I am having difficulty using the Matte Surface command and Exponential Color Mapping.

When Exponential is turned on, the matte object is rendered as a grey object.

Does anyone know how to avoid this?

Thanks

N