PDA

View Full Version : Render Artifacts



DustinBrown
04-21-2008, 12:29 PM
See the attached image. I'm getting random black spots on some of my frames and I'm not sure why. I've made sure that I don't have any weird sub-object anomalies, like overlapping polys or flipped polys. I'm good there. Here are some specs for my render settings:

- Basic 3-point light rig: key, fill, rim. All are spot lights.

- Only the key light is casting a shadow, using a shadow map with a 2048 map size, and fuzziness is set at 4.

- raytraced reflections are enabled

- raytraced shadows are disabled (because I'm using a shadow map)

- rendering at D1 NTSC Widescreen

- My camera is a Perspective camera with AA set to 5, Adaptive SamplingThreshold set to 0.02

I'm against making my surfaces doubles-sided, as it will increase render times and my frames are already taking 15-30min to render, and my project manager hates it when frames take longer than 5min to render :)

Any suggestions are appreciated.

Thanks,
Dustin

tribbles
04-21-2008, 02:24 PM
I had a problem when a couple of non-planar polygons were being rendered - it looks like a similar effect (it was as if only one triangle was being rendered). However, mine were a lot larger, so easier to see what polygon was causing it (can you see it in textured wire mode?)

So, I'd look out for some in that area - and do a limited area render to see if they're eliminated or not.

DustinBrown
04-21-2008, 02:50 PM
Could this have anything to do with the smoothing angel on my surfaces?

- Dustin

DustinBrown
04-21-2008, 05:58 PM
All fixed.

I recalled something I read in Jensen's book on photon mapping. He talks about how photon maps work better when you have large, flat surfaces broken up with some edges, so the map can calculate each section of that area independently instead of trying to calculate the whole thing at once...which can lead to errors.

Now I realize that this isn't a photon map, it's a shadow map, but I went on a hunch that they might work according to the same rule in this case. So I just broke that geometry up a bit (the big polys) and all is well now.

Good book by the way. A bit dry, but enlightening.

http://www.amazon.com/Realistic-Image-Synthesis-Photon-Mapping/dp/1568811470/

Thanks,
Dustin