For example, I have mapped an image with alpha to ivy leaves and I give ivy leaves object ID 1. In the compositor the mask ID 1 ignores the image alpha so the mask is of the square planes which make the ivy leaves.
Is it possible to make the id mask incorporate the image texture alpha?
The object ID does just as it says. It’s looking at the OBJECT which in your case is a plane.
Can you make a render layer just with the ivy leaves and use its alpha channel to create a mask
For more specific advice you need to be more specific with your question and the additional information you supply
I want to use post processing on the visible ivy material without the alpha. Maybe I’ll try what you suggest – seems like it might work. Thanks