TwoSided material

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

Post by CodeHD » Wed Sep 30, 2020 8:03 am

Does the object have a negative scale in Y direction?
Normals won't show flipped in edit mode unless you apply the scale.

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Dade
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Re: TwoSided material

Post by Dade » Wed Sep 30, 2020 8:46 am

CodeHD wrote:
Wed Sep 30, 2020 8:03 am
Does the object have a negative scale in Y direction?
Normals won't show flipped in edit mode unless you apply the scale.
It is the reason I asked if it is instanced, a negative transformation can change the handiness of the transformation (from right to left hand and vice versa) and flip normals.
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CEROE
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Re: TwoSided material

Post by CEROE » Wed Sep 30, 2020 4:42 pm

You have taught me something! The object was negative in the X direction. Once the scale was applied the normals flipped.

It's interesting to see how Cycles and Lux materials treat this scenario differently. Cycles materials leave the normals direction until the scale is applied, while Lux materials treats the normals as if the scale was already applied.

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Dade
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Re: TwoSided material

Post by Dade » Wed Sep 30, 2020 8:00 pm

CEROE wrote:
Wed Sep 30, 2020 4:42 pm
It's interesting to see how Cycles and Lux materials treat this scenario differently. Cycles materials leave the normals direction until the scale is applied, while Lux materials treats the normals as if the scale was already applied.
I would call it a Cycles bug: as proof, having two different results if the scale is applied or not, it is intuitively wrong. It is a common mistake, the transformation handiness swap is tricky to handle correctly (i.e. I have done the same mistake but I have fixed it sometime ago).
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CEROE
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Re: TwoSided material

Post by CEROE » Wed Sep 30, 2020 9:00 pm

Thank you for taking the time to educate me on this!

BTW: I'm the person who contacted you about the PolarGrid project many months back. After a creative hiatus, I'm back on the project again.

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Phantom107
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Re: TwoSided material

Post by Phantom107 » Sun Nov 15, 2020 11:10 pm

Many thanks for adding the TwoSided material as my usecase is now possible in LuxCoreRender! I'll be supporting :D

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