Mental Ray baking problems

ImSlightlyBored

So I'm trying to process within Max 9 (normally use xnormal but I cant now)
I can bake everything fine - get good normal maps, diffuse, etc, so I know how to work it and work the cage fine.

But whenever I get to rendering an Ambient Occlusion map (MR) it always borks up - I always get the low poly intersecting with the high, which blacks out a lot of the AO. I've followed the eat3D tutorial on this to a tee before now, and riki's low model intersected the high like mine, but he didnt get black splodges.

I assume theres something very very simple I'm missing here, but I can't for the life of me find out. Here's a batch of images showing my models, (high/low) the cage I'm using, my dialog boxes and the difference between normal bake (good) and AO (MR) Bake (bad.)

MoP

I think you might just need to set an option in the lowpoly's Object Properties to stop it either being rendered by mental ray, or stop it from recieving/casting shadows.
I seem to recall that's the fix anyway. I always just use standard Skylight for baking AO so I never run into that issue

ImSlightlyBored

hey, thanks for the quick reply
I was doing everything right, and I've followed the eat3D sample and another tutorial correctly, but it seemed to be a version difference (guess I'm not running the same version of max)
The workaround was to throw an edit poly on to the LP after the cage is set, then select all faces and hit hide selected. Seemed to work - but it won't let me do any other seemingly valid workaround. Hide selected object? forget about it. Object properties - uncheck renderable? nope.

Seems a little picky. But its sorted now.
In my travels I found a different technique (is this what you are on about?)
http://www.game-artist.net/forums/vbarticles.php?do=article&articleid=37