PDA

View Full Version : matte opacity/render passes

karma101
05-03-2004, 09:35 PM
Hi

Ive had a look around for some details about setting this up and found some over at xsibase. However i still cant get it to work very well. So i thought i should ask you guys here.

Ive got a large scene with lots of objects, one of these objects i need to render out in a separate pass for compositing reasons.
However this object is obscured by other objects. So i my alpha channel for my main objects to have "cutouts" where the obscuring objects are. In maya its real easy to set this up by adjusting a parameter called matte opacity in the shader setup.
In XSI i find it to be rather non intuitive.

Heres my aproach

1: Select main object, place it in a separate layer
2: Select everything else and place that in a layer
3: Create passes based on layers
4: ????? (some sort of overide material??)

Worst case senario i would have to make a duplicate of my scene and set the shaders to complete black and complete white then add these image sequences as alphas...

Another thing, ive heard that cluster(shaders) can cause real problems with overrides etc is this still the case even with xsi4.0?


Thanks in advance!
Ablefish
05-04-2004, 12:08 AM
The most straight forward thing to do would be to select the object you want to isolate and go Pass->Edit->RGBA matte to create a new pass which will set up the partitions and over-rides for you.

With passes you should never have to save any more scene duplicates. That was one thing I was very glad to leave behind with Maya.
karma101
05-04-2004, 09:37 AM
ok thanks dude. turns out ive got a fairly tricky scene here with lots of transparency etc so in the end i did it with just separate b/w passes that i used as alphas. But thanks for pointing me in the right direction!
CGTalk Moderation
01-18-2006, 04:00 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.