Cycles/EEVEE: Clamp various shader inputs on the Principled BSDF #112774

Alaska · 2023-09-23T14:31:29+02:00

Alaska commented

2023-09-23 14:31:29 +02:00

Clamp various shader inputs in the Principled BSDF to avoid
physically incorrect materials, and to fix some discrepancies
between Cycles SVM, Cycles OSL, and EEVEE.

Clamp various shader inputs in the Principled BSDF to avoid physically incorrect materials, and to fix some discrepancies between Cycles SVM, Cycles OSL, and EEVEE.

👎 2 😕 2

Alaska added the

Module

Render & Cycles

label 2023-09-23 14:31:29 +02:00

Alaska added 1 commit 2023-09-23 14:31:46 +02:00

a1117a9f2b Clamp various inputs

Alaska requested review from Brecht Van Lommel 2023-09-23 14:31:53 +02:00

Alaska requested review from Lukas Stockner 2023-09-23 14:32:03 +02:00

Alaska requested review from Weizhen Huang 2023-09-23 14:32:11 +02:00

Alaska added 1 commit 2023-09-23 14:47:27 +02:00

d33d36abae Don't clamp anisotropic twice

Alaska commented

2023-09-23 14:47:47 +02:00

A quick list of the benefits of each clamp:

Subsurface
- Fixes a discrepancy between Cycles SVM compared to Cycles OSL/EEVEE. SVM allowed negative values while the others didn't.
Specular
- Fixes negative values producing negative reflections.
Roughness/Sheen Roughness/Coat Roughness
- Fixes a discrepancy between Cycles and EEVEE. Cycles would render like min(abs(roughness), 1.0), while EEVEE would render like max(roughness, 0.0)
Specular Tint
- Fixes a discrepancy between Cycles and EEVEE with extreme values and fixes some weird results with extreme values.
Sheen/Coat
- https://devtalk.blender.org/t/principled-v2-feedback-discussion-thread/24997/487
Emission Strength
- Fixes a discrepancy between Cycles SVM and OSL (OSL didn't support negative values). The other alternative is to allow OSL to support negative values.
Alpha
- Fixes weird results with Cycles when below 0, and fixes a discrepancy between Cycles and EEVEE when it's below 0.

Note: Not all clamping is needed in all places (SVM, OSL, and EEVEE), because some of this is already handled when processing the relevant closures. But I put the clamps in all three places just so it's clear, with the exception of clamping Subsurface in OSL.

A quick list of the benefits of each clamp: - Subsurface - Fixes a discrepancy between Cycles SVM compared to Cycles OSL/EEVEE. SVM allowed negative values while the others didn't. - Specular - Fixes negative values producing negative reflections. - Roughness/Sheen Roughness/Coat Roughness - Fixes a discrepancy between Cycles and EEVEE. Cycles would render like `min(abs(roughness), 1.0)`, while EEVEE would render like `max(roughness, 0.0)` - Specular Tint - Fixes a discrepancy between Cycles and EEVEE with extreme values and fixes some weird results with extreme values. - Sheen/Coat - https://devtalk.blender.org/t/principled-v2-feedback-discussion-thread/24997/487 - Emission Strength - Fixes a discrepancy between Cycles SVM and OSL (OSL didn't support negative values). The other alternative is to allow OSL to support negative values. - Alpha - Fixes weird results with Cycles when below 0, and fixes a discrepancy between Cycles and EEVEE when it's below 0. Note: Not all clamping is needed in all places (SVM, OSL, and EEVEE), because some of this is already handled when processing the relevant closures. But I put the clamps in all three places just so it's clear, with the exception of clamping Subsurface in OSL.

👎 2

Alaska changed title from ~~Cycles/EEVEE: Clamp various shader inputs~~ to Cycles/EEVEE: Clamp various shader inputs on the Principled BSDF

2023-09-24 01:27:20 +02:00

Brecht Van Lommel referenced this issue from a commit

2023-09-25 12:42:42 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel referenced this issue from a commit

2023-09-25 12:44:56 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel referenced this issue from a commit

2023-09-25 13:26:44 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel referenced this issue from a commit

2023-09-25 13:58:37 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel referenced this issue from a commit

2023-09-25 14:10:12 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel referenced this issue from a commit

2023-09-25 14:35:57 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel referenced this issue from a commit

2023-09-25 14:53:39 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel commented

2023-09-25 17:53:12 +02:00

This was incorporated in #112848, with two changes:

Clamp subsurface to 0..1
Clamp specular_tint >= 0, but allow > 1

This was incorporated in #112848, with two changes: * Clamp subsurface to 0..1 * Clamp specular_tint >= 0, but allow > 1

Brecht Van Lommel referenced this issue from a commit

2023-09-25 19:52:57 +02:00

Shaders: clamp various shader inputs for Principled BSDF

Brecht Van Lommel manually merged commit a03ee1af81 into main

2023-09-25 19:53:53 +02:00

Alaska referenced this pull request

2023-09-26 11:39:22 +02:00

Shader: Only clamp undefined or unsupported inputs of Principled BSDF #112895

AgentA1cr commented

2023-09-26 16:48:51 +02:00

First-time contributor

Please don't clamp negative values unnecessarily. Sometimes, physically incorrect results are an artistic choice, and I've used negative values to achieve interesting effects in various projects.

Colin Basnett referenced this issue from a commit

2023-09-27 07:30:22 +02:00

Shaders: clamp various shader inputs for Principled BSDF

dameeb1989 commented

2023-10-02 19:53:12 +02:00

First-time contributor

I am a stylized 3D artist and my work depends on "breaking" some of the shaders. Bad idea, please don't assume everyone wants "physically correct" output. It hinders creativity.

👍 2

Brecht Van Lommel referenced this issue from a commit

2023-12-05 01:37:13 +01:00

Shaders: clamp various shader inputs for Principled BSDF

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Cycles/EEVEE: Clamp various shader inputs on the Principled BSDF #112774