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 ).

1. wayne Says:
   December 12th, 2008 at 10:04 am

   thanks for the insite, i’m trying to use the id output in nuke but can’t seem to get it to work properly. everything is fine in houdini it’s just the comping i’m struggling with…

   thanks
   w

2. geneome Says:
   December 12th, 2008 at 10:47 am

   Hi Wayne,

   Your site has some amazing work. Absolutely stunning!

   As for Nuke, are you exporting from Houdini as an EXR? If that’s the case, I’ve read about object ID issues in Nuke, but not being a Nuke user I haven’t watched the subject closely. But I do remember this: http://www.vfxtalk.com/forum/nuke-object-id-exr-t11509.html?t=11509 and maybe it might help.