br1 Posted March 29, 2012 Share Posted March 29, 2012 Hi. I'm having strange black horizontal lines in my fluid renders. I can hardly get rid of them, the only way I found to minimize the issue is to reduce the volume step size to a really low value, but rendertimes drastically increase. It's only happening with shadow maps, not ratrayced shadow / pbr rendering, but as the look is set as I want with shadow maps, I'd rather try not switching to raytrace. Any hints / tips ? thx Bruno. Quote Link to comment Share on other sites More sharing options...
ikarus Posted March 29, 2012 Share Posted March 29, 2012 Have you tried increasing the blur on your shadow map? Quote Link to comment Share on other sites More sharing options...
rtarantino Posted March 30, 2012 Share Posted March 30, 2012 I am not sure without looking through your hip though( Looks awesome by the way!!), Did you try to use volumevoxeldiameter() expression for volume step size?? You can add this render parm to each object level. I often use this for volume. For high res volume, it gives me pretty good volume step size (accurate) to start rendering with. Especially if you scale camera or your volume, I think it's good to use. If you still have same issue, sorry I don't know what makes that and you should post this to SESI forum instead. Cheers Quote Link to comment Share on other sites More sharing options...
br1 Posted March 30, 2012 Author Share Posted March 30, 2012 Have you tried increasing the blur on your shadow map? Yes I tried that but I loose detail much faster than those artifacts so it's not really efficient. Quote Link to comment Share on other sites More sharing options...
br1 Posted March 30, 2012 Author Share Posted March 30, 2012 I am not sure without looking through your hip though( Looks awesome by the way!!), Did you try to use volumevoxeldiameter() expression for volume step size?? You can add this render parm to each object level. I often use this for volume. For high res volume, it gives me pretty good volume step size (accurate) to start rendering with. Especially if you scale camera or your volume, I think it's good to use. If you still have same issue, sorry I don't know what makes that and you should post this to SESI forum instead. Cheers I never tried using volumevoxeldiameter(), I'll keep that in mind ! I think I found out what is causing the issue. I'm using standard volumes like boxes and spheres to sculpt out excessive smoke with the volumemix node. I was using low-res volumes and it sometimes resulted in stepped output. Increasing the isoOffset sampling and adding a volume blur node seems to have fixed the shadow on that test frame. I'll now render a few more frames and see if it solves the problem. cheers Bruno Quote Link to comment Share on other sites More sharing options...
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