Layer A is a background such as a sky
Layer B is a black and white image that acts as a mask
Layer C is a different clip which only displays in the black or white area of layer B
My specific application is projecting onto a 3d set that has a cutout shape in the foreground. I would like to project a different image onto the cyc in the background and be able to project another layer inside a mask that is the same shape as the foreground cutout.
can you draw me something of what you are actually trying to achieve?
- im trying to help other people as well.
this is something that quite a few people have asked for.
but there are sufficient variations - that not every solution works for everyone.
Ideally the mask layer could be any one from 2 to 7 and every layer above that would appear in the mask.
That way you could have layers 1 thru 4 as background layers appearing as full screen. Layer 5 as the mask for the alpha channel and then still have 3 layers to muck around with inside the mask.
You could try using trans white on the matte with the brown layer beneath it then use a blend mode on the brown layer over the blue one. Some of the new blending modes might include an alpha stencil or luma stensil. If you don't have any success try premultiplying the matte into and RGB .mov and using it as a standard black and white movie and do the same as decribed above.
The only surefired way I can do this is in Shake, AE or Combustion right now as a trackmatte or using a luma or alpha matte.
Again, It is very much needed in logo and live compositing where you composite a logo over either another layer or a live input. The only way you can make everything transparent around the logo, unless it is pure black and/or white is to use a matte, Richard.
Richard this is much like trans black/white except we would need it for any range or combination of colors. You can achieve this in Quartz.
Reply With Quote