Artifacts in AO map

Paulod

Hi.
I have been trying to render my AO maps using the max RTT dialog but keep coming up against the problem displayed below.

When rendering the faces that are the same on the high and low polly get terrible ray miss errors. The only way i can fix this problem is by moving the high away from the low polly.

Is there a way i can get these maps to render without doing this fix or do i always have to model outside the low polly when baking AO in max?

A little about the render set-up:

• AO matt on the high only.
• Rendering at 2048X2048
• Default matt on the low polly.
• View-port lighting used.

Thanks for the help in advance, if you would like an more info just holla and i will give it ASAP.

Paul

Mark Dygert

Looks like you're low poly is intersecting with your high or the cage is clipping into the meshs.

It would help to see the objects in the viewport with the cage turned on, preferably with shaded turned on in the cage settings.

Right click on your low poly object, open object properties and turn off cast shadows or renderable (I forget which). IF that doesn't work, go into element mode of your low poly hide all and then bake.

Also if you're rendering in mental ray you don't need to apply the AO material. Just use the RTT MentalRayAO output element.

Paulod

Thanks for the quick response Vig, I tried your suggestions. The places where i am getting the errors are polygons that share the exact same world space on the low polly and hjgh polly.

I think the problem is the faces being in exactly the same world space so i am getting Zfighting / Clipping errors. I thought there would be a way around this problem but i suspect that i will just have to apply a push to my high polly.

THE 5

Push the highpoly? o.O
In the Cage modifier itself there is a "push" slider, turn that up a little.

Paulod

The cage isnt the problem. The error only happens when the low is sharing the same world space as the high. So i put a push on the high to move it slightly further away from the low. If that's wrong then i am lost as to what im doing wrong.

Piflik

Hide all faces of the Lowpoly (not the Object, but the Geometry, using an edit Poly Modifier). This will prevent MRay from hitting the wrong surface and reporting a Ray Miss.

Mark Dygert

Yep like Piflik (and I said earlier probably not all that clear tho),
Select your low poly
Go down into edit poly either polygon or element mode and hide all
Then click back on the projection modifier so now only the cage and your high poly are visible in the viewport
Bake and see what you get, its a pretty common problem with Max and MR/AO.

Paulod

Ah ok, i didn't quite get that in your first post Vig. This problem has been bugging me for almost 1 year .

Thanks all of you for your help.

EDIT: Hiding the faces worked perfectly.

undoz

Piflik wrote: »

Hide all faces of the Lowpoly (not the Object, but the Geometry, using an edit Poly Modifier). This will prevent MRay from hitting the wrong surface and reporting a Ray Miss.

That's a cool trick. Thanks!