On Tuesday 04 Aug 2009, Mark wrote: > Hi all, > > I get this error when rendering an animation, but only at certain > frames: > > Non-convex polygon (Error: r3raster: 401) > > Rendering continues, but huge artifacts appear. Only a few frames > out of 600 are affected but it's a pain in the ***! > > I found out it's related to box rendering. Using fewer larger > boxes or even switching it off completely seems to help, but I > don't want to do that with a quadcore machine! Any ideas?? > It's a very simple scene, camera between large analytical > spheres. > > TIA, > Mark H
I dunno, but it sounds like, due to the box rendering, the camera is partially seeing the inside of something that it's expecting to only see the outside of. Could it be related to the Near clipping plane of the camera? Do the artifacts appear across different render boxes or are they restricted to just particular boxes. If I got something like this I'd try playing with slightly different fields of view, different clipping planes, different depths of focus and adjusting the camera path slightly. As the objects are simple analytical spheres I'd probably try re-sizing or re-creating them too. You could also try using a different number of render boxes so that the box boundaries are in different places i.e. if you were using 4x4 boxes, try using 5x5 instead, just in case the box boundaries are lying exactly across a point; the point would then need to be in both render boxes but one box might interpret it differently to the other box. I've also hit a few strange artifacts when the camera Far clipping plane has been way beyond the scene I'm trying to render and I believe this may be due to precision limits - if you're looking at something a few millimetres away but the far clipping plane is set to millions of metres the fp hardware can run out of dynamic range i.e. it doesn't seem to be able to maintain a resolution of, say 0.001mm when it's also got to cope with stuff that's 1000km away. Just guessing, of course. LeeE
