danw Posted February 10, 2011 Share Posted February 10, 2011 Hey all. I've got a shader built in Houdini 11, which causes occasional NAN (black pixel) errors in my render, and I've traced it back to the normalized normal and normalized incident vectors going into a fresnel node, and in turn a rayhit. When either of the normalize nodes kicks out a zero normal (I presume because it can't normalize them), it kicks out a nasty pixel... and it's random, another time it'll render just fine. Is there any neat efficient way of catching rogue normals, or do I just have to run a check on their length, and two-way-switch them with a random normal when they're missing? Seems a little messy having a bunch of extra nodes just to catch for that. Quote Link to comment Share on other sites More sharing options...
Macha Posted February 10, 2011 Share Posted February 10, 2011 How about you add a tiny tiny tiny component to every normal? Quote Link to comment Share on other sites More sharing options...
danw Posted February 11, 2011 Author Share Posted February 11, 2011 How about you add a tiny tiny tiny component to every normal? Hehe, that may be a less computationally expensive way I guess :-) My catch-missing-normals nodes seem to work okay anyway, most/all NANs are countered, and the ones that slip through don't appear to cause black pixels any more. It doesn't add that much to the render time either... ...but I might switch it out for this to neaten things up. Thanks for the suggestion! Quote Link to comment Share on other sites More sharing options...
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