Ambient Occlusion Problem

[theeastcoastwest]

First off, I am sure the answer to this problem is as easy as un-ticking a box somewhere, but I haven't been able to find anyone discussing the same issue and their resolution.

 

I am rendering furniture models for a design company. They do most of the models, and I only handle the rendering end. The models are modeled in Rhino, exported as 3ds files, and brought into 3DS Max.

 

Not always, but sometimes certain elements of the models appear 0 black when rendered within an AO render. I am applying a Vray light material as an override to the scene using a dirt map tweaked a little differently every time.

 

The objects that appear black in these AO renders have no problem in any other renders. (Raw GI, Raw Light, Specular ...etc) and are able to have textures mapped to them without any problem.

 

I have asked the modelers if perhaps they are doing something on their end, but they aren't really able to provide me with a definitive yes or no.

 

I have attached a picture of the problem.

 

Any help or ideas would be greatly appreciated.

 

Max 2010

Vray 1.5 SP4

[alias_marks]

wish there was an easy fix for this too... It happens when the normals are flipped the wrong way. Doesn't make sense if you ask me. AO should act the same way on both sides of a face... anyone have a fix for this besides going in and manually flipping normals?

 

M-

[theeastcoastwest]

Well, it really doesn't make sense that it would discriminate between different sides of a face like that.

 

However, that completely solved my problem. I don't really mind going through and flipping the few elements one by one. I was just roadblocked by the cause.

 

A very tremendous thank you

[Stephen Thomas]

It should be fine if you make sure 'force 2-sided' is turned on in your render settings. And if you're using a light material then you should also make sure 'emit light on back side' is enabled too.