Some objects render black

[schroeder]

Strange situation here: Rendering still frames, this renders just fine - but if I try to use the pre-pass calculated from the animation mode, these objects, as you can see, render pure black. What could be causing that?

[ene.xis]

double faces (coplanar planes) maybe?

[schroeder]

I thought so too - but no, the geometry is clean.

[vlado]

Are the objects moving at this particular moment?

Best regards,
Vlado

[schroeder]

No, they're stationary at this point. The studs in the wall on the right that are black don't move at all, while the 90-degree section and the small disc do move eventually, but later in the animation.

[schroeder]

Well - I'll be damned. For no apparent good reason, it works now. All day it wouldn't work - last try before heading out the door, and voila, it works.

Weird.

[Clifton Santiago]

Is that strip a glossy material? Did you use LC for glossies? Did you maybe forget to load your LC map? That's what happens to me when I forget...

[pixelstudio]

hmm normals inverted?

[schroeder]

Nope & nope. The normals are fine - has worked fine in several previous "draft' animations sent to client. And no, the material isn't using glossy reflections either. In fact we even ran a test with glossies off as a global switch, and got the same output.

Strange that it's working fine now though.

[schroeder]

Wait - no it isn't.

Everything was looking good then, around frame 2700, a couple objects randomly turned black. This just doesn't make any sense to me. This has worked just fine on numerous other draft animations (of this exact same max file).

[pixelstudio]

hmm then it's getting weirder by the minute )

Yoiu could try merging all in a new max file, see what happends?
Also you sure you dont have any animating materials or somthing?
realy weird
dunno if it is possible but you havent animated the GI properties or something?

[Clifton Santiago]

Are you getting any "too far from origin", or "scene bounding box too large" errors in the vray render messages? Never known them to have an effect on non-reflective/refractive materials, but just an idea.

Did you maybe accidentally animate some geometry that jumps into a coplanar relationship at frame 2700?

[schroeder]

Just for a bit of closure - we ended up re-calculating the irradiance map series (5400 frames...), and it rendered fine. It must have been something with the irradiance maps that was causing the random blackness. Definitely strange though.

When we re-calc'd we manually reset all the vray parameters at the same time just to rule out the possibility that one was changed by accident, somehow causing the problem.

Thanks for your efforts guys in trying to help figure it out.