Dark edges on metal

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Rivental
Posts: 2
Joined: Mon Aug 16, 2021 4:33 pm

Dark edges on metal

Post by Rivental » Wed Sep 01, 2021 6:30 pm

Hello, I have a problem with the metal in luxcore.
How can I get rid of these dark edges?
I had the same problem in Cycles, but when I switched to multiscatter ggx in principled bsdf, the problem just gone.
I don't see the multiscatter ggx option in luxcore.
Attachments
Luxcore
Luxcore
Cycles GGX
Cycles GGX
Cycles Multiscatter GGX
Cycles Multiscatter GGX
Last edited by Rivental on Sun Sep 05, 2021 9:19 am, edited 1 time in total.

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Dade
Developer
Posts: 5524
Joined: Mon Dec 04, 2017 8:36 pm
Location: Italy

Re: Dark edges in metal

Post by Dade » Wed Sep 01, 2021 6:51 pm

The looks like a normal related problem (may a split normals is required). Can you post a test scene ?
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Rivental
Posts: 2
Joined: Mon Aug 16, 2021 4:33 pm

Re: Dark edges in metal

Post by Rivental » Wed Sep 01, 2021 7:25 pm

Yes, maybe this is problem with normals. But i don't understand why multiscatter ggx solves this problem.
https://drive.google.com/file/d/1MFND83 ... sp=sharing

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Dade
Developer
Posts: 5524
Joined: Mon Dec 04, 2017 8:36 pm
Location: Italy

Re: Dark edges in metal

Post by Dade » Tue Sep 07, 2021 11:08 am

Rivental wrote:
Wed Sep 01, 2021 7:25 pm
Yes, maybe this is problem with normals. But i don't understand why multiscatter ggx solves this problem.
https://drive.google.com/file/d/1MFND83 ... sp=sharing
The problem is in how your NURBS are exported to Lux. This is a part of the mesh exported:

nurbs.jpg

As you can see, there are a lot of problems:

- very low triangles count;
- faceted;
- normals flipped (they point inside the object).

My suggestion is to transform the NURBS in triangle mesh inside Blender, so you have full control of what is going on and than render (i.e. export the scene) with LuxCore.
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