Maya ambient occlusion pass renders only white IF animation

[Anonymous]

Hey all,

I am a Maya novice. I am using Maya 2016. I have modeled the inside of a spaceship. I can render current frame and get a great ambient occlusion result. I can batch render (single frame) and also get my desired ambient occlusion pass.  BUT, if I render an animation (name.#.ext), I get white frames. 

I have been trouble shooting for days and searching Google but can't figure this out. I am rendering with mental ray.  Please help. Let me know what info you need from me.

Thanks so much. 

[Anonymous]

Attached here is the AO single frame render

[Anonymous · Accepted solution]

I believe I figured this out. This scene has a pilot encased inside the cockpit of a ship. Originally, when I rendered this, the AO pass was black so I thought I needed to reverse the normals. Then I figured out that I needed to change the max distance in my Mental Ray AO node to more than 0. And I never put the normals back to there original direction. Why this would result in a rendered frame that looks fine and an animation that is all white, is beyond me. So I fixed the normals and all is good.