Didn’t think the image plane series was complete enough so I tacked on this little diddy. I covers how to get object (or primitive) ids using image planes in Houdini and what you can do with them in the compositor using the lumakey COP. The compositor part I learned from SYmek, who I feel is an integral part of the Houdini community (and who I had an argument with about points on the Sunflow forum a while back :) ).