compositing mattes problems

[BigBucks]

Hi all,

I was hoping some of you could help me with my compositing problems.

I'm currently using maya shaders with matte opacity set to black hole to render out my mattes, but when I comp the layers I'm seeing a gap:( http://www.lambethdigital.com/public/mentalray/comp_problems.jpg
I'm fairly new to this so I figure it is something simple I'm overlooking. Any help with this would be greatly appreciated as I'm on a tight deadline:D

Also what is the preferred workflow for render passes? I have been looking at ctrl_buffer and P_MegaTk stuff. Any preferences?

[bmcaff]

Try turning off Premultiply in the frameduffer section of your render globals.