Rotoscope / Composite help needed

robertwerden

Well-known member
Ok so I have some 3d animation and some live video I need to composite.

I have a 3d object that I rendered both the alpha channel as well as the object in seperate avi videos.

The question is, in sony vegas how do I arrange the clips so the 3d object is on top and there is no bleed through from the live video.

I have been playing with the parent child composite buttons and I just cant figure it out.
 
I don't get what you mean -- what did you to to render the "alpha channel" and the object as separate .avis?
 
I have 3 clips.
The first is a live shot
The second is a 3d animation that I want to overlay on the live shot
the third is a alpha channel mask of the 3d animation where the object in the animation is black and the rest of the screen is white so it can be used as a mask.

So the result I want is the 3d object in the animation to be composited over the live shot video clip.

The problem is in sony vegas you need to arrange the clips correctly in order.

The settings for composite modes as well as parent and child tracks are what is confusing me.
I can get my alpha mask to composite on my live shot and I can get my 3d animation to show only the desired area through the mask, but I cant get all 3 to work together.
The number of possible combinations is huge when you have 3 clips.
 
You need to have the matte (b/w) in the track above the 3D object. Then you make the lower track the child track. Then, you change the upper track's compositing mode to Multiply (Mask). Then, you drop a luminance mask into the matte clip. But with the way you have it, you might have to invert the mask.

Then, the footage can be put in a track underneath it.

But . . . why didn't you just render out the 3D object into an .avi with an alpha channel?
 
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