material problem issue

[patro]

hi,
I did some test this morning... just to add more info about the problem!

well.. I try to understand a log message from Luxrender - "P" s must match "N" s - or something like this.
so I increase the fillet edge on the chamferbox from 3-> 10 ( from odd-> to equal) and no shading problem - smooth was on, no log error.

then I try to re render the scene with 3 edge for the fillet... again shading issue was visible. I try to increase the fillet to a equal number 4... the export of the scene failed... 3ds max crashed. I try with 4 for more than 4 times.. every time max crashed. strange that it crashed with 4 and not with 10.
I will try with other numbers of edge for the fillet... odd and equal. edit: max crash strangely only with 4 edges for the fillet

but the problem is also persisting for complex imported obj in 3ds max. I don't know if tessellating the geometry could help... but this solution will securely increase rendering time and have not much sense.

[patro]

well.. I tried to export from 1 segment for the fillet to 10.
max always crash when using 4 edges for fillet.
the issue is less visible while increasing the fillet segments.
as I say applicable to max standard geometry... but not to imported mesh.

[patro]

any news about the issue? fixing?
thanks

[hedphelym]

I can give it a look later today, but I guess my knowledge on such and advanced topic is limited.
So the best would be if PerPixel had some extra time to look at it again..

[patro]

I can give it a look later today, but I guess my knowledge on such and advanced topic is limited.
So the best would be if PerPixel had some extra time to look at it again..

thanks
please could you try to PM him?

[PerPixel]

Send me your max file.

Im trying to reproduce that with a chamfer box + meshsmooth with no succes.

[patro]

Send me your max file.

Im trying to reproduce that with a chamfer box + meshsmooth with no succes.

file send.
I used only chamferbox... with the smooth option in chamferbox setting flagged the issue is visible.. when the smooth is disabled the issue disappear.

[patro]

please consider that the issue is less less visible with a matte material and so on.....
to have the issue high contrasted and visible in render you need to use mirror or metal with u/v exponent set to 0.001.
if you use u/v exponent set to 0.000(mirror) the obj are rendered black but this is a bug of the material.

[PerPixel]

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.

[patro]

OK
thank you for trying to solve the problem.
I will follow your advice. the only problem.... is that I have also this problem on complex mesh exported from rhinoceros as 3ds or obj.
your advice is very difficult to follow on such a geometry.
I hope that a "2 sided" material option will added to all material... this would fix a problematic behavior of some exporter like the one I'm experiencing!
thank you again