Shader: Add Conductor BSDF Node #114958

Alaska · 2023-11-16T05:24:10+01:00

Alaska commented

2023-11-16 05:24:10 +01:00

Add Conductor BSDF Node to the shader editor.

This node is basically the Glossy BSDF, but with different Fresnel
options, and the anisotropy input is interpreted differently to match
the Principled BSDF's interpretation of these inputs.

This node supports F82 and Conductor fresnel options.

F82 allows for the replication of Principled BSDF Metallic materials
The Conductor fresnel allows users to input n, k values to easily
recreate real life metals.
- A "artist friendly" Conductor Fresnel has also been added
  to allow users to work in colors instead of n, k values.

Images:

Node with the 3 fresnel types:

F82 Tint	Conductor - Artistic	Conductor

When using the same settings, the F82 Tint mode will produce the same result as a Metallic Principled BSDF.

F82 Fresnel on Conductor BSDF	Metallic Principled BSDF

Comparing the F82 Tint mode to Conductor - Artistic, the most notable thing is that Conductor - Artistic can't produce as strong of an edge tint as F82 Tint, with many combinations producing no noticable tint (like the example image below). This generally matches the MaterialX setup for a Artistic Conductor.

F82 Fresnel	Conductor - Artistic "Fresnel"

The Conductor mode can reproduce any material that can be created with the Conductor - Artistic mode, and possibly more? This is done by defining the n, k values directly rather than defining colors and turning them into n, k values. The main benefit this offers is that it allows people to take n, k values from real life materials if material accuracy is important. A list containing some n, k values can be found here: https://physicallybased.info/

Copper `n, k`	Gold `n, k`	Chromium `n, k`

Add Conductor BSDF Node to the shader editor. This node is basically the Glossy BSDF, but with different Fresnel options, and the anisotropy input is interpreted differently to match the Principled BSDF's interpretation of these inputs. This node supports F82 and Conductor fresnel options. - F82 allows for the replication of Principled BSDF Metallic materials - The Conductor fresnel allows users to input `n, k` values to easily recreate real life metals. - A "artist friendly" Conductor Fresnel has also been added to allow users to work in colors instead of `n, k` values. --- Images: Node with the 3 fresnel types: |F82 Tint|Conductor - Artistic|Conductor| |-|-|-| |![F82 Fresnel - Node.png](/attachments/863b1bbd-8542-4201-b5f9-5bc0a9b6af92)|![Conductor Artistic - Node.png](/attachments/1bbcb6db-37c7-44f3-a4e8-9594dbefc569)|![Conductor Fresnel - Node.png](/attachments/418ef332-837d-4d30-ab17-288baa71b59c)| When using the same settings, the `F82 Tint` mode will produce the same result as a Metallic Principled BSDF. |F82 Fresnel on Conductor BSDF|Metallic Principled BSDF| |-|-| |![F82 Conductor - Render.png](/attachments/bc91d63f-bb06-42b7-ba00-0622e04374fe)|![Metallic Principled - Render.png](/attachments/9582fd4f-79b5-41b0-a6bd-8bb02a3b9c6c)| Comparing the `F82 Tint` mode to `Conductor - Artistic`, the most notable thing is that `Conductor - Artistic` can't produce as strong of an edge tint as `F82 Tint`, with many combinations producing no noticable tint (like the example image below). This generally matches the MaterialX setup for a Artistic Conductor. |F82 Fresnel|Conductor - Artistic "Fresnel"| |-|-| |![F82 Conductor - Render.png](/attachments/bc91d63f-bb06-42b7-ba00-0622e04374fe)|![Conductor - Artistic "Fresnel" - Render.png](/attachments/64fc665f-9dfd-4a62-894f-76213977ba5b)| The `Conductor` mode can reproduce any material that can be created with the `Conductor - Artistic` mode, and possibly more? This is done by defining the `n, k` values directly rather than defining colors and turning them into `n, k` values. The main benefit this offers is that it allows people to take `n, k` values from real life materials if material accuracy is important. A list containing some `n, k` values can be found here: https://physicallybased.info/ |Copper `n, k`| Gold `n, k`|Chromium `n, k`| |-|-|-| |![Copper nk - Render.png](/attachments/678befa2-e4df-4eda-9511-a89ba539c13f)|![Gold nk - Artistic "Fresnel" - Render.png](/attachments/117481ec-e128-425d-8c94-6634aa97f203)|![Chromium nk - Artistic "Fresnel" - Render.png](/attachments/c14fbf75-696e-49ee-bac4-cef7a5dac792)|

Conductor Fresnel - Artistic - Node.png

349 KiB

F82 Fresnel - Node.png

344 KiB

Metallic Principled - Render.png

355 KiB

F82 Conductor - Render.png

355 KiB

Conductor Fresnel - Node.png

403 KiB

Copper nk- Render.png

316 KiB

Chromium nk- Render.png

289 KiB

Conductor Fresnel - Artistic - Render.png

341 KiB

Gold nk- Render.png

314 KiB

👍 1

Alaska added the

Module

Render & Cycles

label 2023-11-16 05:24:10 +01:00

Alaska added 6 commits 2023-11-16 05:24:22 +01:00

46bec5539d Intial Implementation of Conductor BSDF

- Node appears in shader editor
- Material renders in EEVEE

TODO: Work on Cycles

5d6f651aef Intial Implementation of Conductor BSDF

- Node appears in shader editor
- Material renders in EEVEE

TODO: Work on Cycles

54c91f8bd3 Intial Cycles support

The material now (incorrectly) renders in Cycles in both SVM and OSL

TODO:
 - Add support for Tint to SVM
 - Use seperate "Conductor BSDF" case instead of reusing glossy closures.
 - Update SVM and OSL to be based on the Principled BSDF Metallic instead of the Glossy BSDF

0d0c0df3d9 Remove unused Microfacet options

482fb698a2 Switch Cycles to it's own unique shader type

6ace770d3b Merge branch 'main' into metallic-bsdf

Alaska requested review from Brecht Van Lommel 2023-11-16 05:24:29 +01:00

Alaska requested review from Lukas Stockner 2023-11-16 05:24:37 +01:00

Alaska commented

2023-11-16 05:25:39 +01:00

Intially when I mentioned adding this to Blender, it was going to be called the "Metallic BSDF". But I renamed it to the "Conductor BSDF" in line with MaterialX.

Please let me know if you want the name changed.

Intially when I mentioned adding this to Blender, it was going to be called the "Metallic BSDF". But I renamed it to the "Conductor BSDF" in line with MaterialX. Please let me know if you want the name changed.

xZaki commented

2023-11-16 15:35:36 +01:00

First-time contributor

What is the difference between this and Glossy BSDF?

Alaska commented

2023-11-16 20:14:28 +01:00

What is the difference between this and Glossy BSDF?

The Conductor BSDF has support for the F82 tint like the Principled BSDF.
Anisotropy is interpreted differently from the Glossy BSDF.
Fewer Microfacet Distributions are supported.

> What is the difference between this and Glossy BSDF? - The Conductor BSDF has support for the F82 tint like the Principled BSDF. - Anisotropy is interpreted differently from the Glossy BSDF. - Fewer Microfacet Distributions are supported.

Lukas Stockner commented

2023-11-18 19:38:11 +01:00

Generally this is good to have, but I think we should a) support the full range of Microfacet distributions and b) have an enum for switching between F82 Fresnel and the proper conductive Fresnel (which currently is only available through OSL), potentially also the Artist-Friendly Base/Edge Color reparametrization since enough other tools use it and it's quite straightforward to add without a new closure.

Alaska commented

2023-11-19 04:08:12 +01:00

b) have an enum for switching between F82 Fresnel and the proper conductive Fresnel (which currently is only available through OSL)

Is the OSL "proper conductive Fresnel" osl_closure_conductor_bsdf_setup() in /intern/cycles/kernel/osl/closures_setup.h or is it something else?

potentially also the Artist-Friendly Base/Edge Color reparametrization since enough other tools use it and it's quite straightforward to add without a new closure.

Sorry, it's not clear to me what you mean by this. Do you mean add an option to switch between a Base/Edge color input, and a n, k input? For both the F82 Fresnel and the Conductive Fresnel?

> b) have an enum for switching between F82 Fresnel and the proper conductive Fresnel (which currently is only available through OSL) Is the OSL "proper conductive Fresnel" `osl_closure_conductor_bsdf_setup()` in `/intern/cycles/kernel/osl/closures_setup.h` or is it something else? > potentially also the Artist-Friendly Base/Edge Color reparametrization since enough other tools use it and it's quite straightforward to add without a new closure. Sorry, it's not clear to me what you mean by this. Do you mean add an option to switch between a Base/Edge color input, and a `n, k` input? For both the F82 Fresnel and the Conductive Fresnel?

Alaska added 2 commits 2023-11-19 05:06:15 +01:00

871d0fba84 Merge branch 'main' into metallic-bsdf

b48090ecad Add Beckmann dsitrobution to Conductor BSDF node

Alaska added 3 commits 2023-11-20 12:25:38 +01:00

9b1a441acb Add Conductor Fresnel to Conductor BSDF

Notable changes from previous revision of Conductor BSDF:
- There are three "Fresnel Types" that can be selected on the node.
- Conductor Fresnel - Artistic (Default)
- Uses `bsdf_microfacet_setup_fresnel_conductor()` in Cycles. Takes a Color `Base` and `Tint` input with automatic code to turn it into `n, k` values (fresnel_conductor uses `n, k` values).
- F82 Tint Fresnel (Old default)
- Uses `bsdf_microfacet_setup_fresnel_f82_tint()` in Cycles. Takes a Color "Base" and "Tint" input. This option should match the a metallic Principled BSDF material.
- Conductor Fresnel
- Uses `bsdf_microfacet_setup_fresnel_conductor()` in Cycles. Takes in `n, k` values.
- Various functions have been added to support the new `Conductor Fresnel - Artistic`.
- For example, I've added `conductor_ior_from_color` and `conductor_extinction_from_color` fucntions to get `n, k` values from color `Base` and `Tint` inputs.
- Formula is taken from the paper `"Artist Friendly Metallic Fresnel", Ole Gulbrandsen, 2014`.
- These are the same formulas used by MaterialX in the `artistic_ior` node.
- General other changes (E.G. Change names of certain inputs, adjust default values, etc.)

TODO:
1. Fix the MaterialX node setup for when we're using the "Conductor Fresnel Type".
2. Adjust names and the descriptions of inputs to explain things. (Feedback from developers would be appreciated).
3. Check with Cycles developers to see if the names of the newly added functions are alright.
4. Wait for general code review. See if any other changes are wanted.

cb261fa16a Merge branch 'main' into metallic-bsdf

21ffc1d77d Adjust names of inputs

Add a code comment

Alaska commented

2023-11-20 12:29:38 +01:00

I just wanted to add the commit message of one of the recent commits to explain recent changes. Also it includes a list of TODOs that I couldn't figure out. Help on the TODOs would be appreciated.

Notable changes from previous revision of Conductor BSDF:

There are three "Fresnel Types" that can be selected on the node.
- Conductor Fresnel - Artistic (Default)
  - Uses bsdf_microfacet_setup_fresnel_conductor() in Cycles. Takes a Color Base and Tint input making it "artist friendly" compared to the Conductor Fresnel option (see below). Automatic code is run to turn these colors into n, k values for fresnel_conductor (which uses n, k values).
  - EEVEE behaves the same as F82 Tint. This causes rendering differences between EEVEE and Cycles.
- F82 Tint Fresnel (Old default)
  - Uses bsdf_microfacet_setup_fresnel_f82_tint() in Cycles. Takes a Color "Base" and "Tint" input. This option should match a metallic Principled BSDF material.
- Conductor Fresnel
  - Uses bsdf_microfacet_setup_fresnel_conductor() in Cycles. Takes n, k values as inputs.
  - EEVEE takes the n, k values and turns them into Base and F82 tint colors and uses them in the F82 tint formula. This causes rendering differences between EEVEE and Cycles.
Various functions have been added to support the new Conductor Fresnel - Artistic.
- For example, I've added conductor_ior_from_color and conductor_extinction_from_color functions to get n, k values from color Base and Tint inputs.
  - Formula is taken from the paper "Artist Friendly Metallic Fresnel", Ole Gulbrandsen, 2014.
  - These are the same formulas used by MaterialX in the artistic_ior node.
General other changes (E.G. Change names of certain inputs, adjust default values, etc.)

TODO:

Fix the MaterialX node setup for when we're using the "Conductor Fresnel Type". (I couldn't figure out how to detect which "Fresnel Type" was being used. So I couldn't switch between using colors and using the n, k values in MaterialX. Help would be appreciated)
Adjust names and the descriptions of inputs to explain things. (I don't know what to put in the description for most of these. And the feedback on the names would be appreciated).
Check with developers to see if the names of the newly added functions are alright.
Wait for general code review. See if any other changes are wanted.

I just wanted to add the commit message of one of the recent commits to explain recent changes. Also it includes a list of TODOs that I couldn't figure out. Help on the TODOs would be appreciated. --- Notable changes from previous revision of Conductor BSDF: - There are three "Fresnel Types" that can be selected on the node. - Conductor Fresnel - Artistic (Default) - Uses `bsdf_microfacet_setup_fresnel_conductor()` in Cycles. Takes a Color `Base` and `Tint` input making it "artist friendly" compared to the `Conductor Fresnel` option (see below). Automatic code is run to turn these colors into `n, k` values for `fresnel_conductor` (which uses `n, k` values). - EEVEE behaves the same as F82 Tint. This causes rendering differences between EEVEE and Cycles. - F82 Tint Fresnel (Old default) - Uses `bsdf_microfacet_setup_fresnel_f82_tint()` in Cycles. Takes a Color "Base" and "Tint" input. This option should match a metallic Principled BSDF material. - Conductor Fresnel - Uses `bsdf_microfacet_setup_fresnel_conductor()` in Cycles. Takes `n, k` values as inputs. - EEVEE takes the n, k values and turns them into `Base` and `F82 tint` colors and uses them in the F82 tint formula. This causes rendering differences between EEVEE and Cycles. - Various functions have been added to support the new `Conductor Fresnel - Artistic`. - For example, I've added `conductor_ior_from_color` and `conductor_extinction_from_color` functions to get `n, k` values from color `Base` and `Tint` inputs. - Formula is taken from the paper `"Artist Friendly Metallic Fresnel", Ole Gulbrandsen, 2014`. - These are the same formulas used by MaterialX in the `artistic_ior` node. - General other changes (E.G. Change names of certain inputs, adjust default values, etc.) TODO: 1. Fix the MaterialX node setup for when we're using the "Conductor Fresnel Type". (I couldn't figure out how to detect which "Fresnel Type" was being used. So I couldn't switch between using colors and using the n, k values in MaterialX. Help would be appreciated) 2. Adjust names and the descriptions of inputs to explain things. (I don't know what to put in the description for most of these. And the feedback on the names would be appreciated). 3. Check with developers to see if the names of the newly added functions are alright. 4. Wait for general code review. See if any other changes are wanted.

Brecht Van Lommel commented

2024-01-10 20:02:32 +01:00

@LukasStockner, can you review this one?

Alaska added 1 commit 2024-01-11 01:17:09 +01:00

45b1a5906a Merge branch 'main' into metallic-bsdf

Lukas Stockner self-assigned this 2024-01-22 03:05:27 +01:00

Alaska referenced this pull request

2024-01-29 02:05:32 +01:00

Shader: Add specular tint to Glass BSDF #114354

Alaska added 1 commit 2024-02-23 12:18:51 +01:00

aa10c5d56d Merge branch 'main' into metallic-bsdf

Alaska added 1 commit 2024-02-23 12:20:58 +01:00