16bit Matte From 3d

[user_deleted]

Hi there,

I had problems with a premultiplied 3d rendering in 16bit. When comping the generated footage I had some of the typical premultiplication problems. The footage became transparent etc. Even converting the matte to 8bit did not solve the problem. I talked to the 3D guys and they rendered a 8bit matte and everything was fine. Can someone explain me that problem? I thought I read something about that somewhere but i could not remember what was written.

Thx Nanuk

(Shake 4, Mac OSX)

[user_deleted]

Bit difficult to tell without seeing the images, but it doesn't sound like a bit depth problem to me.
You mentioned the footage became transparent. This could indicate the original render hadn't had an alpha channel. (Amongst many other possibilities of course)

FR

[user_deleted]

It had an alphachannel. Trust me!

[user_deleted]

did you check the numbers on your matte and make sure it was really white? It could appear white but may not be.

[user_deleted]

I had some strange numbers at the edges of the matte. That is true. But inside the matte everything seemed to be ok.

[user_deleted]

what kind of strange numbers?