PerPixel wrote:It wont be a problem on high density mesh.
PerPixel wrote:I can confirm the normal do point at the right place and the issues seems to be that you have a large flat surface followed by an angle. Your smoothing group in max by default would set a chamfer box to have all surface smoothing together so the vertices sharing the flat surface and the chamfer edge create the bug. Adding move segments or setting a different smoothing group on the flat surface solve this.
I'm not sure if this is the expected behavior in Luxrender but I dont know what else I can do with the normals.
Most probably having the material 2 sided won't help (actually most materials are 2 sided). What happens with shading normals is that your ray can hit the surface from above if you consider the geometric normal, but from below if you consider the shading normal. In such a case the ray will be reflected below the surface and be rejected.
Material "matte" "color Kd" [0.352941 0.352941 0.352941]
#Nk Data path :
#Not using NKData
"string name" ["copper"]
"float vroughness" [0.100000]
"float uroughness" [0.100000]
patro wrote:I'm not saying that you are wrong... or do you read something like this?
my experience is that other rendering engine like maxwell, fryrender had this kind of problem in the past... and using the flagging 2sided function... will not solve the normal issue... but don't show the black patch issue in the rendered image.
this function were requested from user. this is not my opinion but what happens!
obviously I'm not here to teach you how to write Luxrender.. I can only make some requests
I asked only for the code part to add to the material definition in the lxs... to activate the 2sided function in my materials... if it's not just activated by default in Luxrender. that's all.
naturally I followed the advice of perpixel to add smoothing group and/or to increase tessellation... but this require a lot of new faces to solve the issue.... and it's manageable with a simple max geometry... but is very difficult to do that with a lots of imported dense mesh.
I will have export time increasing.. with probably hanging and so on............
tomb wrote:A dense mesh will usually - by just being dense - not have such a big difference between interpolated (shading) normals and the geometric normals, and as such will not have this problem. The problem is a very well known problem in CG and is most noticeable when turning on smoothing on a mesh with too few triangles and/or has a high curvature (i.e. abrupt changes in the geometric normals between faces).
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