BPY: Cannot link new Mix Node Output to any other node if data_type is changed #117966

New Issue

samlovesmath · 2024-02-07T23:22:37+01:00

samlovesmath commented

2024-02-07 23:22:37 +01:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3070 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.23

Blender Version
Broken: version: 3.6.8, branch: blender-v3.6-release, commit date: 2024-01-15 12:55, hash: f6ae60f3eeda
Worked: N/A (only versions after 3.3LTS use the new Mix node. Attempted on Blender's latest Steam version, 4.0.2. Same error still exists + can be replicated using the same file.)

Short description of error
Currently trying to build a set of nodes for a new material using Blender's Python coding. After using Python to create a new Mix Node (not the legacy Mix Node) with the Color type ("RGBA" via Python) and try to link the output to my Principled BSDF's "Base Color" input, the two nodes do not get connected. Instead, the BSDF's Base Color input has a "visual link" that connects to a spot behind its own BSDF. It is not visible unless you pull the link away from the BSDF Base Color input. The Mix does not get connected, as the BSDF's Base Color does not change.

This issue also exists when changing the Mix Node to "VECTOR" via Python.
This issue still exists when connecting the Mix Node's output to any other input.
There is no issue trying to connect it using the Factor/Float version that is used by default. It is only after I change the Data Type of the Mix node that there is an issue.
The legacy mix node does not have this issue.

Exact steps for others to reproduce the error

Manually create a new object, and ensure it has a new material. Make sure Use Nodes is enabled for the material.
Using Python (or manually), remove all of the nodes within your new material.
Via Python:
a. Create a new Shader node and a new Mix node (the new version, "ShaderNodeMix", not the legacy "ShaderNodeMixRGB").
b. Change the data type of the Mix node to Color (data_type = "RGBA").
c. Link the output of the "Result" in Mix node to your input of another node (using links.new())

This is my first time reporting, but I've used Blender for quite a long time, and this seems like a bug to me. Let me know if I'm wrong.

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3070 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.23 **Blender Version** Broken: version: 3.6.8, branch: blender-v3.6-release, commit date: 2024-01-15 12:55, hash: `f6ae60f3eeda` Worked: N/A (only versions after 3.3LTS use the new Mix node. Attempted on Blender's latest Steam version, 4.0.2. Same error still exists + can be replicated using the same file.) **Short description of error** Currently trying to build a set of nodes for a new material using Blender's Python coding. After using Python to create a new Mix Node (_not_ the legacy Mix Node) with the Color type ("RGBA" via Python) and try to link the output to my Principled BSDF's "Base Color" input, the two nodes do not get connected. Instead, the BSDF's Base Color input has a "visual link" that connects to a spot behind its own BSDF. It is not visible unless you pull the link away from the BSDF Base Color input. The Mix does not get connected, as the BSDF's Base Color does not change. This issue also exists when changing the Mix Node to "VECTOR" via Python. This issue still exists when connecting the Mix Node's output to any other input. There is no issue trying to connect it using the Factor/Float version that is used by default. It is only after I change the Data Type of the Mix node that there is an issue. The legacy mix node does not have this issue. ![image](/attachments/7f8df590-9ac5-4c34-82f5-5bc93a2e283f) **Exact steps for others to reproduce the error** 1. Manually create a new object, and ensure it has a new material. Make sure Use Nodes is enabled for the material. 2. Using Python (or manually), remove all of the nodes within your new material. 3. Via Python: a. Create a new Shader node and a new Mix node (the new version, "ShaderNodeMix", not the legacy "ShaderNodeMixRGB"). b. Change the data type of the Mix node to Color (data_type = "RGBA"). c. Link the output of the "Result" in Mix node to your input of another node (using links.new()) This is my first time reporting, but I've used Blender for quite a long time, and this seems like a bug to me. Let me know if I'm wrong.

mixnode_test.txt

885 B

image.png

94 KiB

blender3.6.8LTS_MixBSDFNode_Python_report.blend

703 KiB

system-info.txt

26 KiB

samlovesmath added the

labels 2024-02-07 23:22:38 +01:00

Scurest commented

2024-02-08 00:21:55 +01:00

I don't see the misdrawn noodle, but the socket not being connected is an error in your script. Dupe of #103395.

tldr Use _node_mix.outputs[2] for the Result output socket in Color mode.

I don't see the misdrawn noodle, but the socket not being connected is an error in your script. Dupe of #103395. tldr Use `_node_mix.outputs[2]` for the Result output socket in Color mode.

samlovesmath commented

2024-02-08 00:42:25 +01:00

Very interesting, thank you. I originally didn't notice there were more than one output listed, since trying to get the console to auto-complete always returns the same word (since, of course, all of those outputs have the same name, silly me). Made me think it only had one output at all times.

The misdrawn noodle only shows when you drag it off of the input node that the Result goes into. When I did it with the Principled Shader, the "input spot" that Python tried create with a link was hiding behind the shader, so I didn't even notice it until I tried to take out the link part that goes into Base Color. So in the end, Python still tried to link it anyways. Not sure if that is a particular visual bug only on my end.

Thank you for the correction, and apologies for the incorrect report!

Very interesting, thank you. I originally didn't notice there were more than one output listed, since trying to get the console to auto-complete always returns the same word (since, of course, all of those outputs have the same name, silly me). Made me think it only had one output at all times. ![image](/attachments/63b6fbd9-8f34-4230-9371-11a3e4252cfc) The misdrawn noodle only shows when you drag it off of the input node that the Result goes into. When I did it with the Principled Shader, the "input spot" that Python tried create with a link was hiding behind the shader, so I didn't even notice it until I tried to take out the link part that goes into Base Color. So in the end, Python still tried to link it anyways. Not sure if that is a particular visual bug only on my end. Thank you for the correction, and apologies for the incorrect report!

image.png

6.1 KiB

Iliya Katushenock commented

2024-02-08 15:58:40 +01:00

So i'll close as duplicate of #103395.

Iliya Katushenock closed this issue

2024-02-08 15:58:43 +01:00

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