TwoSided material

Discussion related to the LuxCore functionality, implementations and API.
CEROE
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Re: TwoSided material

Post by CEROE » Tue Sep 29, 2020 4:42 pm

Actually, it is the definition of your material to be asymmetric, you need to click on "Double Sided" and to use the same parameters for front and back face ("BF"):
Yes, this was the issue with the extra glossiness!

Have you addressed the issue about mirroring? When the objects are mirrored the faces change from frontside to backside.

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Dade
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Re: TwoSided material

Post by Dade » Tue Sep 29, 2020 5:34 pm

CEROE wrote:
Tue Sep 29, 2020 4:42 pm
Have you addressed the issue about mirroring? When the objects are mirrored the faces change from frontside to backside.
But isn't that expected ? I mean it is the normal of the surface to be flipped by the mirror operation (i.e. it is not related to LuxCore, it is just what Blender does) :?:
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CEROE
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Re: TwoSided material

Post by CEROE » Tue Sep 29, 2020 5:54 pm

But isn't that expected ? I mean it is the normal of the surface to be flipped by the mirror operation (i.e. it is not related to LuxCore, it is just what Blender does) :?:
Mirroring an object in Blender does not flip the normal faces. Not in my experiences. I've mirrored twigs many times for variation and Cycles materials do not flip the faces from backside to frontside. The first time this happened for me is mirroring and using Lux materials.

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Dade
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Re: TwoSided material

Post by Dade » Tue Sep 29, 2020 9:05 pm

CEROE wrote:
Tue Sep 29, 2020 5:54 pm
Mirroring an object in Blender does not flip the normal faces. Not in my experiences. I've mirrored twigs many times for variation and Cycles materials do not flip the faces from backside to frontside. The first time this happened for me is mirroring and using Lux materials.
If the normal is not flipped, material will not be. If it is flipped, the material will be. If you select, inside Blender, the original object and the mirrored one, how do the normals look ?
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CEROE
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Re: TwoSided material

Post by CEROE » Tue Sep 29, 2020 9:18 pm

Using same file and mirroring the object Y Global you can see the difference below:
Attachments
mirror_Cycles.png
mirror_Lux.png

CEROE
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Re: TwoSided material

Post by CEROE » Tue Sep 29, 2020 9:23 pm

Referring to previous post, if it is not obvious, the top image is Cycles and the bottom image is Lux.
If the normal is not flipped, material will not be. If it is flipped, the material will be. If you select, inside Blender, the original object and the mirrored one, how do the normals look ?
The normals do not flip.

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Dade
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Re: TwoSided material

Post by Dade » Tue Sep 29, 2020 10:28 pm

Frankly, I have no idea what I'm looking at. Try to post a test scene explaining what is the problem.
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CEROE
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Re: TwoSided material

Post by CEROE » Tue Sep 29, 2020 11:00 pm

The normals do not flip on the mirrored object, but the frontside/backside material switches in Lux. This does not happen in Cycles (Top render in previous post).

Below shows the normals of the mirrored object.

Lux is switching the frontside/backside material on a mirrored object.
Attachments
normals_of_mirrored_object.PNG

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Dade
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Re: TwoSided material

Post by Dade » Tue Sep 29, 2020 11:16 pm

Is the mirrored object an instance ?
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CEROE
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Re: TwoSided material

Post by CEROE » Tue Sep 29, 2020 11:22 pm

Is the mirrored object an instance ?
No, it is a duplicate (Shift D)

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