a couple material bugs

[Alessandro Padovani]

This is related to #2120 and reported here for better handling. Test scene included 2lobe.duf.

bug. daz dual lobe. The ior is not computed correctly with a daz image, in this case the daz image is used directly as input instead of converted with the math node. The math node is used correctly with a standard texture.

# daz dual lobe
ior = 1.1 + 0.7 * daz dual lobe specular reflectivity

bug. daz color effect. The daz color effect is not used for principled. In this case we need to revert the fac, since with principled we need the translucent fac rather than the diffuse fac.

# daz color effect
principled fac = 1 - bsdf fac

# principled bsdf v2 blender 4.x
# the base color and subsurface weight are eventually driven by the daz color effect
base color = mix(factor = daz translucency weight,
                 A = daz base color,
                 B = gamma(daz translucency color, 3.5))
subsurface weight = daz translucency weight

# principled bsdf blender 2.x 3.x
# the base color and subsurface are eventually driven by the daz color effect
base color = daz base color
subsurface = daz translucency weight

Below the correct conversion for the test scene with extended principled materials, where we fix the color effect and the ior. Both for blender 3.x and 4.x.

Of course let me know if something is not clear.

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[Alessandro Padovani]

Issue #2120 was marked as a duplicate of this issue.

[Thomas Larsson]

I will be gone tomorrow, will check this on Friday.

[Alessandro Padovani]

4.2.0.2190

Works fine for my test scene thank you for the fix. Unfortunately doesn’t work in the “real case“ #2120 where I get an error.

https://www.daz3d.com/xue-and-expressions-for-genesis-81-female

steps:

1. import Xue as extended principled

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[Thomas Larsson]

That was a piece of dead code that was revived by mistake. It is removed now.

However, I didn’t get the error because it occurred when an extra translucency group is generated, and that doesn’t happen for Xue. Here the material method = Extended principled and Xue has volumetric skin, and then no extra translucency group should be created, so I don’t understand why you got that error.

[Alessandro Padovani]

Commit beab4e8.

The error is fixed thank you. The translucency is on the iris material which doesn’t come with the default Xue figure, you have to apply the Xue eye materials, which unfortunately don’t work fine. Test scene included. In this case there’s a color effect over translucency that’s not converted correctly. That is, the color effect can be over sss if there’s translucency + volume that’s converted to sss. Or over translucency if there’s translucency alone without volume.

Below the correct implementation of the iris material for extended principled, where the color effect is connected to translucency. We need to revert the fac as usual. In general the color effect should always have both the color and fac outputs connected, otherwise it doesn’t work fine.

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[Alessandro Padovani]

Xue with eye materials, aka color effect over translucency

[Joe Morris @ FAST Animation Studio Toolz]

Thanks very much for working on this I appreciate that!

[Thomas Larsson]

Xue iris fixed in last commit.

[Alessandro Padovani]

Commit c943b7c.

Works fine thank you for the fix.

Unfortunately transluncency works fine with cycles but not with eevee. I’m afraid the eevee translucency is much more simplified by design, thus doesn’t produce the correct effect. Will look into this some more if we can find a workaround, but at the end this may be a eevee limitation.

[Joe Morris @ FAST Animation Studio Toolz]

Again?I appreciate it.That's my favorite character

[Alessandro Padovani]

4.2.0.2209

It seems the new eevee settings fixed the translucency. Works fine now.

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