you can add all the objects you want to the render layer
then you can assign black hole shaders to the objects you don't want to show in the render but still cast shadows or occlude other objects
that's one way of doing it...
i think i've only gotten the shadow pass preset to work once, but that might have been because i actually included the lights in that layer
that's a "Ch" pronounced as a "K"
Computer skills I should have:
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