Shader: Add Metallic BSDF Node #105008

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Aaron Carlisle merged 10 commits from Alaska/blender-manual:metallic-bsdf into blender-v4.3-release 2024-11-12 19:11:59 +01:00
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hair.rst
holdout.rst
mix.rst
metallic.rst
principled.rst
hair_principled.rst
volume_principled.rst

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.. _bpy.types.ShaderNodeBsdfMetallic:
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Alaska marked this conversation as resolved Outdated

There is a WARNING: Title overline too short. I believe these ***** should be as long as the title itself.

There is a `WARNING: Title overline too short.` I believe these ***** should be as long as the title itself.
Metallic BSDF
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.. figure:: /images/node-types_ShaderNodeBsdfMetallic.webp
:align: right
:alt: Metallic BSDF node.
The *Metallic* :abbr:`BSDF (Bidirectional Scattering Distribution Function)`
node is used to recreate the appearance of metals.
Inputs
======
Base Color :guilabel:`F82 Tint Only`
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Looking at Inputs in hair_principled.rst, I think it's preferable to have subsections like Common, F82 Tint, and Physical Conductor, instead of mixing all the inputs.

Looking at `Inputs` in `hair_principled.rst`, I think it's preferable to have subsections like `Common`, `F82 Tint`, and `Physical Conductor`, instead of mixing all the inputs.
Color of the material when viewed straight on.
Edge Tint :guilabel:`F82 Tint Only`
Color of the material when viewed at a 82° angle.
IOR :guilabel:`Physical Conductor Only`
The Index of Refraction (sometimes denoted by n) per color channel. Combined with *Extinction*, this controls the base
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You could say "Refractive index per color channel. This is the real part of a complex refractive index, scientifically denoted as n".
Just saying Index of Refraction feels a bit messy when the IOR is complex. Also saying using base and edge color is just another model, mentioning it here sounds like the two models are connected, but they are not.

You could say "Refractive index per color channel. This is the real part of a complex refractive index, scientifically denoted as n". Just saying Index of Refraction feels a bit messy when the IOR is complex. Also saying using base and edge color is just another model, mentioning it here sounds like the two models are connected, but they are not.
and edge color of the metallic material.
Extinction :guilabel:`Physical Conductor Only`
The Extinction Coefficient (sometimes denoted by k) per color channel. Combined with *IOR*, this controls the base
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Similar here, I would prefer "Extinction coefficients per color channel. This is the imaginary part of a complex refractive index, scientifically denoted as k".

Similar here, I would prefer "Extinction coefficients per color channel. This is the imaginary part of a complex refractive index, scientifically denoted as k".
and edge color of the metallic material.
Roughness
Sharpness of the reflection; perfectly sharp at 0.0 and smoother with higher values.
Anisotropic :guilabel:`Cycles Only`
Amount of anisotropy. Higher values give elongated highlights along the tangent direction;
negative values give highlights shaped perpendicular to the tangent direction.
Anisotropic Rotation :guilabel:`Cycles Only`
Rotates the direction of anisotropy, with 1.0 going full circle.
Compared to the *Glossy BSDF* node, the direction of highlight elongation
is rotated by 90°. Add 0.25 to the value to correct.
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This is called Anisotropy in the UI

This is called Anisotropy in the UI
Normal
Normal used for shading; if nothing is connected the default shading normal is used.
Tangent
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This is called Rotation in the UI

This is called Rotation in the UI
Tangent used for shading; if nothing is connected the default shading tangent is used.
Properties
==========
Distribution
Microfacet distribution to use.
:GGX:
GGX microfacet distribution.
:Multiscatter GGX:
Takes multiple scattering events between microfacets into account.
This gives more energy conserving results, which would otherwise be visible as excessive darkening.
:Beckmann: :guilabel:`Cycles Only`
Beckmann microfacet distribution.
Fresnel Method
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This is called Fresnel Type in the UI

This is called Fresnel Type in the UI
Metallic Fresnel type to use.
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This description does not give more information than the title. We could say "Models for describing metal appearance, by specifying the apparent color or the physical IOR.

This description does not give more information than the title. We could say "Models for describing metal appearance, by specifying the apparent color or the physical IOR.
:F82 Tint:
Uses the Adobe F82-Tint formula for the metallic fresnel.
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Add a link to the F82-Tint model https://helpx.adobe.com/content/dam/substance-3d/general-knowledge/asm/Adobe%20Standard%20Material%20-%20Technical%20Documentation%20-%20May2023.pdf
This allows for artist friendly control of the color near the edge of the material
to simulate a complex IOR.
:Physical Conductor:
Accepts :abbr:`IOR (Index of Refraction)` and Extinction coefficients, measurements from real world
metals to replicate a more accurate rendering of metals than the *F82 Tint* Fresnel type.
:abbr:`IOR (Index of Refraction)` and Extinction coefficients, otherwise known as n, k,
commonly referred to as a complex :abbr:`IOR (Index of Refraction)`, can be found
from source like the `Physically Based database for CG artists <https://physicallybased.info/>`__
and `Refractive Index nk database <https://refractiveindex.info/>`__.
Outputs
=======
BSDF
Standard shader output.