Weird noisy shading error [SOLVED]

I'm getting this weird white noise streaking error on some meshes in my scene. I havent got a clue what it is. There is only one shader being used, and two materials, one material for the arches and another for all the other meshes.
In ofusion without shadows it looks like:



What is strange is that all the meshes in that scene, the big floor plane etc, everything except those long pieces of wall render ok.

I noticed that sometimes when I first open the scene in ofusion, sometimes it renders correctly, sometimes after moving the camera a little the white noise goes away.



It's only on the exact same meshes.

In our app, the noise is there 100% of the time, here's a little video.

2.7MB
http://www.flow3d.org/ad/weirdshading.wmv

Anyone come across this before? I get no errors in the shader log, and tried cg.dll 1.4x and 1.5x incase there was a difference there.

THanks

Probably a z buffer issue, or a eye vector issue in the shader, it cant be defined from static screenshots (in the video there are mesh parts totally white, is this the issue?)

When you see the noise, test by increasing the depth bias in the pass material

Can this be reproduced with a single mesh in the scene, or only with other meshes?

Is your shader multipass?

Hey, I was using Max 2008 Demo, which seems to be working fine. And I think I solved the problem. The original scene was a Max 9 scene and for some reason those 4 cloned meshes that were getting the reder glitch seem to not have converted properly.

I checked in max 9 with my new materials and those worked, so I deleted the offending meshes and merged the original max 9 ones in again. This seems to have fixed it.

I guess it was some kind of glitch in the upgrading the scene that caused it.

Took me most of yesterday and a couple of hours this morning to figure that out. I even saved out as OBJ and 3DS meshes and imported them again with the same problem. So max must have broken the actual geometry somehow.

Anyway, all is good again, if anyone upgrades to 2008, Ofusion and ShaderFX both seem to work great