Ambient Occlusion, Z Depth, Object ID
Creating an ambient occlusion pass should be a fairly simple thing to do. That is until you involve transparency maps. I first created a new layer and applied a mib_occlusion shader to all the objects. I then found out that it didn't occlude the transparency maps I had for the leaves on the ground. Obviously leaves arnt an important thing in the scene but it was very frustrating for me to accept the fact that Maya will nto do this. I had to find a way! Turns out there is a way :D I had to create a perticular shading network that was very frustrating to set up as there is very little tutorials on the web so I spent my time just doing trial and error to get it finally working. A screenshot of the shading network is below.
Here is the proof that it does work!
Object ID was a pretty easy pass to do and it doesn't take long to render at all. I just created a bunch of different SurfaceShaders with different colours and applied it to different objects, making sure none of them overlap so it's easy to select whatever you wanted.
After a bit of research I found there are multiple ways of creating a Zdepth pass but the easiest way is to apply a LuminanceDepth preset to the render layer, break the connections it had on the shader and input my own numbers of a small min distance and a max distance of around 14,000. This was calculated using the Distance Tool.
We have also been asked by our VFX guy to render out a Normal pass and World Point Position pass so he can take it into Nuke if any major lighting changes need to be made. I will post my progress on this at a later date.