ID Mask is black, WHY?

Hi, Im trying to put objects into trcked footage via cycles, i got a tutorial from this guy called Daniel, but when I follow the compositing, the end result is not correct. I tracked back to the Id Mask, its just black so the add and mix nodes factors are not working correctly . . . what am I missing?

You mask is blank because you are trying to use a Material Index as an Object index.

You should be routing IndexOB to ID Mask, not IndexMA to ID Mask.

Under the Render context open up layers and add enable Object Index. Then connect the Index OB to the ID Mask and render again.

Hey, thx Atom. Apreciate very much.

I have a similar problem but I think my settings are right, could you give me any help?

The sphere is Pass index 1, but when select 1 in ID mask all is white.


Check out this file.

One thing that is not mentioned that often and might stump new users is that once you add a new output option to your render pass you have to render again for that option to become populated with the result. By default pass index is not enabled so if you enable it and route it it will remain blank until you render then it will become populated.


26_pass_index.blend (521 KB)

Thanks Atom…your file works fine…I will recheck my file, because I’m sure I pressed F12 before looked in compositor.