View Full Version : Render Glitch driving me insane

07-02-2009, 07:33 AM
I have a proceduraly driven water surface - grid with (subdivision), and no matter how I set the subdivision and anything else I can tweak, or how many threads I let it use, I'm getting these clear horizontal band errors. I'm running 64 bit, 8Gb ram, not disk thrashing or anything, same error in XP or Win 7, rebuilt the object & surface, still get it. LW 9.6 or 9.5:help: still get it.
Any ideas, anyone, please?
The boss has signed off on the 'look' so I'm really stuck if I can't render it!

07-02-2009, 08:47 AM
Can you explain your rendering config? How many cores/processors?

Does the band's location vary or is it always in that one location?

Are you using procedural displacements on the water surface? Which ones?

Easiest would be to upload the scene file and see if others can replicate the problem, but if that isn't viable, giving as much detail as you can about the scene would at least help us narrow down what isn't causing the problem.

07-02-2009, 09:29 AM
Dual quad, scene uses 65% of 8Gb ram when renderibg.bands are there whether rendered one thread 2 threads 4 threads 8 threads. no change rendering in more/less segments same place on same frame always, seem to come & go in different places on different frames.
'Sea' mesh driven by bunch of procedurals - big ripples driving Y for waves, distorted X & Z by slow big turbulence, added ripples around objects and enveloped blob for underwater eruption with many particles etc later in scene
Poly massive - too big to upload really (a lot of sea gets seen in a single camera move.)
2nd still attatched - 50 frames later

07-02-2009, 11:17 AM
My guess is the error is not in the displacement but in the texture reflection. Try a render with out reflection.

07-02-2009, 06:43 PM
Turn off the procedurals one at a time til it goes away? Or - it could be that certain type of procedural, anything that use noise I think, that doesn't stay consistent, you have to bake it...

07-03-2009, 08:00 AM
The problem is in the reflections, removing ray traced reflections completely cures it ! - changing recursion etc makes no difference.
The only way I can make it go away is to reduce the ripples driving the 'Y' displacement to 1 or lower, but that makes the waves too small!
Altering the sub-division makes no difference.
It looks like an overload in a buffer or something - but like I said, changing the segment memory or number of threads makes no difference.

07-03-2009, 09:15 AM
Not much hair left by now - think laterally - oldest 64 bit LW I've got is 9.4, so export as v9.2 scene and re-install 9.4.
Renders Ok (fingers crossed)
Dontcher love progress?:p

07-06-2009, 04:46 AM
Renders in 94 apart from the quality of the hypevoxels - Arrgh!