Wolfwood Posted May 16, 2007 Share Posted May 16, 2007 (edited) I remember Jim mentioning something about lights when he had a similar problem. I can't find the thread though, I think it was on SESI's forum.Perhaps move your lights further away from the object and see if it helps? Aye. As it turns out moving the lights only really helped in that scene. I never really figured out why those burnouts occur. I suspect at certain angles the model freaks out. At one point I got pretty close to narrowing down which term was the culprit but then 'work' reared its ugly head and I haven't had time to go back to it. (I'm secretly waiting for a job to come in that requires hair so I* can look into this again.) * When I say, "I", I really mean Mario. Edited May 16, 2007 by Wolfwood Quote Link to comment Share on other sites More sharing options...
jason_slab Posted May 16, 2007 Share Posted May 16, 2007 pity about that, hopfully H9 has a new hair shader j Quote Link to comment Share on other sites More sharing options...
Marc Posted May 17, 2007 Author Share Posted May 17, 2007 I'm not entirely sure you'll get better than spice's shader. Especially not from SESI... no offense, but shaders aren't their strong point . Quote Link to comment Share on other sites More sharing options...
jason_slab Posted May 17, 2007 Share Posted May 17, 2007 I'm not entirely sure you'll get better than spice's shader. Especially not from SESI... no offense, but shaders aren't their strong point . yeah i guess u'r right, but it would be nice if they could get a shader like spice's and make it work properly!! jason Quote Link to comment Share on other sites More sharing options...
Wolfwood Posted May 17, 2007 Share Posted May 17, 2007 yeah i guess u'r right, but it would be nice if they could get a shader like spice's and make it work properly!! Just for the record, I'm not sure what causes those burn outs. I might be something as simple as a bug in the shader, or a implementation oversight. It could even be a issue with the model itself and Arno (spice) could have implemented it perfectly. It also possible that those hotspots are correct but since model doesn't support multiple scattering the illumination isn't being spread around. Maybe its time to go back and take another look. Fresh eyes might provide some insight. Quote Link to comment Share on other sites More sharing options...
jason_slab Posted May 17, 2007 Share Posted May 17, 2007 Just for the record, I'm not sure what causes those burn outs. I might be something as simple as a bug in the shader, or a implementation oversight. It could even be a issue with the model itself and Arno (spice) could have implemented it perfectly. It also possible that those hotspots are correct but since model doesn't support multiple scattering the illumination isn't being spread around.Maybe its time to go back and take another look. Fresh eyes might provide some insight. def seems sensitive to light/camera angles, i've been playing around with it using fur, i'm still getting burnouts jason Quote Link to comment Share on other sites More sharing options...
spice Posted May 17, 2007 Share Posted May 17, 2007 Hi All, it sems that those bright spots are a consequence of the limited floating point accuracy of Mantra. However, I'll try to fix this issue. Hence, it would be great to have a simple test scene (with artifacts). Ciao, Arno Quote Link to comment Share on other sites More sharing options...
Wolfwood Posted May 17, 2007 Share Posted May 17, 2007 Hi All,it sems that those bright spots are a consequence of the limited floating point accuracy of Mantra. However, I'll try to fix this issue. Hence, it would be great to have a simple test scene (with artifacts). Ciao, Arno This is a simple scene with a light rotating around a NURBS tube. (Frame 130 seems to have a burn out.) Since most of the lighting calculations take place in a polar space(?) is it possible something is blowing up due to x/0? arno.hip Quote Link to comment Share on other sites More sharing options...
spice Posted May 17, 2007 Share Posted May 17, 2007 This is a simple scene with a light rotating around a NURBS tube. (Frame 130 seems to have a burn out.)Since most of the lighting calculations take place in a polar space(?) is it possible something is blowing up due to x/0? Thanks. No, this is not an "x/0" issue. :-) -Arno Quote Link to comment Share on other sites More sharing options...
Wolfwood Posted May 17, 2007 Share Posted May 17, 2007 No, this is not an "x/0" issue. :-) That's too bad, those are easy to fix. Thanks a ton for looking into this. Quote Link to comment Share on other sites More sharing options...
jason_slab Posted May 18, 2007 Share Posted May 18, 2007 yeah thx spice, it's great to have guys like u around!! jason Quote Link to comment Share on other sites More sharing options...
spice Posted May 18, 2007 Share Posted May 18, 2007 (edited) Hi All, Here is a modified version of my shader (for hair with a circular cross section) which hopefully fixes the "bright spot" issue. It would be great if you could perform some tests to see if it works properly. Ciao, Arno [EDIT: Please reload this version !] arno_hair_far_field_v_1_9.zip Edited May 18, 2007 by spice Quote Link to comment Share on other sites More sharing options...
jason_slab Posted May 18, 2007 Share Posted May 18, 2007 so far so good, i'm setting up a render for the weekend, lets se how it comes out! thx spice jason Quote Link to comment Share on other sites More sharing options...
Marc Posted May 18, 2007 Author Share Posted May 18, 2007 Thanks for all your work Arno, it's much appreciated Quote Link to comment Share on other sites More sharing options...
Wolfwood Posted May 18, 2007 Share Posted May 18, 2007 I just took an old sample and applied the new shader. Seems to work nicely. fur.mpg Quote Link to comment Share on other sites More sharing options...
spice Posted May 18, 2007 Share Posted May 18, 2007 I just took an old sample and applied the new shader. Seems to work nicely. Thanks for testing ! I would really appreciate to see some results obtained with the shader. :-) -Arno Quote Link to comment Share on other sites More sharing options...
jason_slab Posted May 22, 2007 Share Posted May 22, 2007 hey i just noticed that the hair shader isn't using deep shadows? it creates shadows on another surface, but it doesn't seem to self shadow. any ideas? check out the images below: thx j Quote Link to comment Share on other sites More sharing options...
spice Posted May 22, 2007 Share Posted May 22, 2007 heyi just noticed that the hair shader isn't using deep shadows? it creates shadows on another surface, but it doesn't seem to self shadow. any ideas? check out the images below: thx j I will check that tomorrow... -Arno Quote Link to comment Share on other sites More sharing options...
Wolfwood Posted May 23, 2007 Share Posted May 23, 2007 (edited) I will check that tomorrow...-Arno Odds are you just need something like illuminance(P,N,PI_2) { shadow(Cl); // ... // Bunch of awesome stuff // .. Out = Cl; } Edited May 23, 2007 by Wolfwood Quote Link to comment Share on other sites More sharing options...
spice Posted May 23, 2007 Share Posted May 23, 2007 (edited) Odds are you just need something like illuminance(P,N,PI_2) { shadow(Cl); // ... // Bunch of awesome stuff // .. Out = Cl; } Thanks. Here is a version including the shadow call in the illuminance loop.... -Arno arno_hair_far_field_v_1_9_shadow.zip Edited May 23, 2007 by spice Quote Link to comment Share on other sites More sharing options...
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