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View Full Version : Black Hole with falloff - is it possible?


olcho
08-25-2007, 11:59 PM
Does anyone know can something like that be done in Maya?
I have a character model and some cables behind him. For compositing reasons I need to render the character and the cables separately. The order must be like that: First Layer is the character and on top of it - the cables.

Now, I want to make the cables pass alpha to be black where the edges of the character are. Black hole for the character doesn't do the trick, because it removes everything that is behind it. I tried to use Opacity Gain with a -1, which works as the black hole, but the moment I try to controll it using a ramp - it stops working.
The only working solution I have is to make a separate Alpha pass which is to render everthing in white and only the character - black with falloff in the transparency.

But is there a way to make this in one render pass?

Kako
08-26-2007, 05:17 PM
I tried to use Opacity Gain with a -1, which works as the black hole, but the moment I try to controll it using a ramp - it stops working.
Why? Couldn't the ramp map be applied at all? Or was it that you couldn't get the desired range from the ramp?

olcho
08-26-2007, 05:21 PM
The Rampl applies just fine. It just doesn't produce the desired result
I'll post an example soon

olcho
08-26-2007, 10:19 PM
Ok, so this is the example:
I have a body model, with falloff. The Inverse of this is actually going to be the alpha chanel for the body. Then I have the cables layer that go above the character. But some of the cables go behind the body and I do want them to be visible. The Custom Alpha is actually what I wanted to make for the cables, but i couldn't get it to work in the same render.

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08-26-2007, 10:19 PM
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