cpu Posted February 21, 2006 Share Posted February 21, 2006 While rendering a torus with a vex displacement and fast shadows (raytraced) I noticed popping from one frame to the next. it happens when I render shadows, but it's fine when I render without. I've tried a ton of things. Increase displacement bounds, shading quality, level of detail, shadow bias, quantization (-b FLOAT), patch crack (What exactly does that do???), I even increased bucket size. All of these trials were done exclusively to not introduce new issues. Any ideas? It's a very simple test. 1. torus geometry with vex displacement and increase the displacement height to a pronounced amount. 2. light with fast shadows 3. render frame 1 then frame 2 and toggle back and forth. You should see some displacement changing eventhough nothing is animated. Quote Link to comment Share on other sites More sharing options...
stu Posted February 21, 2006 Share Posted February 21, 2006 Have you tried turning the "jitter" value to 0 in the output driver? I tried your example and that's what eliminated the change between frames for me. Quote Link to comment Share on other sites More sharing options...
cpu Posted February 21, 2006 Author Share Posted February 21, 2006 Have you tried turning the "jitter" value to 0 in the output driver? I tried your example and that's what eliminated the change between frames for me. 24919[/snapback] Setting my jitter to 0 doesn't seem to relieve the shadow popping for me. I changed the displacement shader on the torus to VEX fractal dent with these setting: Noise frequency 10 10 10 Noise Amplitude .5 I tried switching from raytraced shadows to zdepth but the popping is still there. It's subtle but still evident. ??? Quote Link to comment Share on other sites More sharing options...
Jason Posted February 21, 2006 Share Posted February 21, 2006 I'm wondering which version of Houdini you're running? Looking at this fix: Houdini 8.0.489: Fixing a problem that leads to incorrect V derivatives of s/t global variables in mantra when raytracing. Perhaps incorrect derivatives are being computed and causing bad filtering of the noise? Quote Link to comment Share on other sites More sharing options...
stu Posted February 21, 2006 Share Posted February 21, 2006 Here's my non-flickering file, created with version 8.0.410: torus.zip Quote Link to comment Share on other sites More sharing options...
cpu Posted February 21, 2006 Author Share Posted February 21, 2006 Here's my non-flickering file, created with version 8.0.410:torus.zip 24928[/snapback] Looks like it was a shading quality and jitter thing. Thanks so much for sending me your example file. It helped a ton. I will try it with a more complicated geometry at work today to see if it solved the issue. Thanks Quote Link to comment Share on other sites More sharing options...
stu Posted February 22, 2006 Share Posted February 22, 2006 Glad it helped, stu Quote Link to comment Share on other sites More sharing options...
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