Eevee Next: Unexpected shadows from curve hair with principled and translucent BSDF #121612

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opened 2024-05-09 11:37:47 +02:00 by Calibrator · 3 comments

Calibrator commented

2024-05-09 11:37:47 +02:00

System Information
Operating system: Linux-6.8.9-arch1-2-x86_64-with-glibc2.39 64 Bits, X11 UI
Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 550.78

Blender Version
Broken: version: 4.2.0 Alpha, branch: main, commit date: 2024-05-08 22:06, hash: 03cd8b359ba5
Worked: Never probably

Short description of error
The shadows of the curve hair with principled bsdf and translucent feel wrong. Especially compared to Eevee Legacy and Cycles

Exact steps for others to reproduce the error
Add sphere, add fur, add light, add principled bsdf and translucent on fur.
Attached blend file and images for comparison.

**System Information** Operating system: Linux-6.8.9-arch1-2-x86_64-with-glibc2.39 64 Bits, X11 UI Graphics card: NVIDIA GeForce RTX 3080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 550.78 **Blender Version** Broken: version: 4.2.0 Alpha, branch: main, commit date: 2024-05-08 22:06, hash: `03cd8b359ba5` Worked: Never probably **Short description of error** The shadows of the curve hair with principled bsdf and translucent feel wrong. Especially compared to Eevee Legacy and Cycles **Exact steps for others to reproduce the error** Add sphere, add fur, add light, add principled bsdf and translucent on fur. Attached blend file and images for comparison.

EeveeHair.blend

1.0 MiB

Cycles_copy.jpeg

13 KiB

Eevee legacy_copy.jpeg

14 KiB

Eevee Next_copy.jpeg

12 KiB

Solid_copy.jpeg

60 KiB

Eevee legacy_copy.jpeg

Eevee Next_copy.jpeg

Calibrator added the

labels 2024-05-09 11:37:48 +02:00

Iliya Katushenock added the

EEVEE & Viewport

label 2024-05-09 11:48:16 +02:00

Iliya Katushenock commented

2024-05-09 11:59:39 +02:00

Member

I strongly not sure if this is correct to compare cycles with eevee. But i can confirm difference between eevee and next one.

I strongly not sure if this is correct to compare cycles with eevee. But i can confirm difference between eevee and next one.

Iliya Katushenock added

EEVEE & Viewport

and removed

EEVEE & Viewport

labels 2024-05-09 11:59:52 +02:00

Calibrator commented

2024-05-09 12:03:26 +02:00

Author

I left the Cycles example cause it looks close to Eevee Legacy. Also Cycles and Eevee Legacy look good in practice on actual hair and the new Eevee looks really bad. I would say a bit of comparison with Cycles is a good idea when it comes to shadows.

I left the Cycles example cause it looks close to Eevee Legacy. Also Cycles and Eevee Legacy look good in practice on actual hair and the new Eevee looks really bad. I would say a bit of comparison with Cycles is a good idea when it comes to shadows.

Clément Foucault commented

2024-05-10 12:16:23 +02:00

Member

This is caused by the thickness approximation #120384. If you plug a value of 0 in the thickness output you get the same behavior.

The tricky part is that the versioning for these material is very tricky. The versionned default should be 0 for translucent materials, set to refraction depth for refractive materials, and left unplugged for SSS. If the material uses any mix of these 3, there is no good choice.

So I foresee a lot of users will run into this pitfall. But I don't consider it a bug for now, it's working as intended.

This is caused by the thickness approximation #120384. If you plug a value of 0 in the thickness output you get the same behavior. The tricky part is that the versioning for these material is very tricky. The versionned default should be 0 for translucent materials, set to refraction depth for refractive materials, and left unplugged for SSS. If the material uses any mix of these 3, there is no good choice. So I foresee a lot of users will run into this pitfall. But I don't consider it a bug for now, it's working as intended.

Clément Foucault closed this issue

2024-05-10 12:16:27 +02:00

Blender Bot added

and removed

labels 2024-05-10 12:16:30 +02:00

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Animation & Rigging

Asset Browser Project Overview

Automated Testing

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Development Management

EEVEE & Viewport

Images & Movies

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Nodes & Physics

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Animation & Rigging

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EEVEE & Viewport

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Reference: blender/blender#121612

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