jesschaco Posted February 4, 2012 Share Posted February 4, 2012 (edited) Hi guys! I have been trying to fix the SSS problem on my flower petal for a couple of days now with no luck. And I am not too familiar with shaders, so I am posting the question here hoping to get some help!!! I used a software called xfrog to model my flower blossoms. Instead of modeling out the actual shape of petals, it uses planes, then applies an opacity map to shape out the petals. However, I am suspecting this method of modeling might be the culprit for the problems I ran into while doing SSS. As you see from my attached images, after I generated point cloud, and applied SSS to my petals, I see weird rectangular problem areas on my petals. I see that the pt cloud I generated was based on the rectangular petals geometry of which might have caused the weird problems during SSS(don't know why the opacity map didn't stop this from happening....). To confirm my suspicion, I just roughly altered the original geometry, and deleted off some rectangular overlapped areas for a test (see attached picture and files). Then here comes another problem: the problem still exists... Now I have no idea what exactly is causing the weird rectangular spots on my petals. I really hope there is a way to fix this without remodeling all the flowers I made Thank you in advance!! sss problem.rar Edited February 5, 2012 by jesschaco Quote Link to comment Share on other sites More sharing options...
jim c Posted February 4, 2012 Share Posted February 4, 2012 Just an FYI - there are no attached images, unless they are in the rar file. Quote Link to comment Share on other sites More sharing options...
moondeer Posted February 5, 2012 Share Posted February 5, 2012 the point cloud generation would have to include your opacity i think. also, the renders seem to be where the polygons have intersected. i am curious about your normals direction. maybe they are reversed? Quote Link to comment Share on other sites More sharing options...
jesschaco Posted February 5, 2012 Author Share Posted February 5, 2012 hmm......what should I do to include my opacity map in the point cloud generation though? the point cloud generation would have to include your opacity i think. also, the renders seem to be where the polygons have intersected. i am curious about your normals direction. maybe they are reversed? Quote Link to comment Share on other sites More sharing options...
moondeer Posted February 5, 2012 Share Posted February 5, 2012 fumbling around with this i was not able to correct the problem. sss in the mantra uber shader does not use opacity when generating its pointcloud. also, i am embarassed to say i also do not get a leaf shaped alpha. i lack the knowledge... but i would like to use the opacity texture map when generating the alpha, then after the visible surface area has been calculated, generate a pointcloud for the sss based on the visible portion of the geometry. i've attached my failed attempt at this. leafsss.zip Quote Link to comment Share on other sites More sharing options...
papicrunch Posted February 8, 2012 Share Posted February 8, 2012 hi, the Ray Bias ( at 0.03 ) in mantra render node / shading / seems to minimize artefact but the scattering change ( disapear ? ). Have Fun, thomas Quote Link to comment Share on other sites More sharing options...
jesschaco Posted February 12, 2012 Author Share Posted February 12, 2012 Thanks you guys for your help!! I will keep playing with it and see what happens Quote Link to comment Share on other sites More sharing options...
Serg Posted February 12, 2012 Share Posted February 12, 2012 Hi, IMO it's a waste of time to use this type of SSS for something without observable or actual thickness, especially point cloud based sss! This kind of thin translucency is best served by a simple double sided diffuse shader... The end result will look more accurate (and without the pc headache) than actual SSS because that stuff is very poorly suited to very thin or no thickness geometry. cheers S Quote Link to comment Share on other sites More sharing options...
jesschaco Posted February 12, 2012 Author Share Posted February 12, 2012 Thanks for the advise Serge! Hi, IMO it's a waste of time to use this type of SSS for something without observable or actual thickness, especially point cloud based sss! This kind of thin translucency is best served by a simple double sided diffuse shader... The end result will look more accurate (and without the pc headache) than actual SSS because that stuff is very poorly suited to very thin or no thickness geometry. cheers S Quote Link to comment Share on other sites More sharing options...
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