Python API: Geometry Nodes object and collection inputs appear disabled in custom panel #89876

New Issue

Antti Tikka · 2021-07-15T15:47:19+02:00

Antti Tikka commented

2021-07-15 15:47:19 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-07-15 12:22, hash: 468d59e496
Worked: -

Short description of error
Geometry Nodes object and collection inputs appear disabled when they are shown in a custom panel. Other types of properties do work. The properties can be accessed as follows: layout.prop(modifier, '["Input_2"]').

Exact steps for others to reproduce the error
Based on the attached file:

Run the script in the text editor to create a panel into the sidebar into a category called "Geometry Nodes"
See that the panel shows the object and collection inputs of the Geometry Nodes modifier of the active cube as disabled

geometry_nodes_object_and_collection_inputs_disabled_bug.blend

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89 **Blender Version** Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-07-15 12:22, hash: `468d59e496` Worked: - **Short description of error** Geometry Nodes object and collection inputs appear disabled when they are shown in a custom panel. Other types of properties do work. The properties can be accessed as follows: layout.prop(modifier, '["Input_2"]'). **Exact steps for others to reproduce the error** Based on the attached file: 1. Run the script in the text editor to create a panel into the sidebar into a category called "Geometry Nodes" 2. See that the panel shows the object and collection inputs of the Geometry Nodes modifier of the active cube as disabled [geometry_nodes_object_and_collection_inputs_disabled_bug.blend](https://archive.blender.org/developer/F10225113/geometry_nodes_object_and_collection_inputs_disabled_bug.blend)

Antti Tikka commented

2021-07-15 15:47:19 +02:00

Added subscriber: @Symstract

Stéphane Chataignié commented

2021-07-15 16:41:53 +02:00

Added subscriber: @Stefakapapy

Stéphane Chataignié commented

2021-07-15 16:41:53 +02:00

This is really an annoying problem. Please fix it.
Thank you for reporting

This is really an annoying problem. Please fix it. Thank you for reporting

Philipp Oeser commented

2021-07-15 17:01:03 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-07-15 17:01:03 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2021-07-15 17:01:03 +02:00

Probably has the same roots as #88655 (PyAPI: template_modifiers doesn't work in the viewport)

Hans Goudey commented

2021-07-20 21:19:31 +02:00

Added subscriber: @HooglyBoogly

Hans Goudey commented

2021-07-20 21:19:31 +02:00

I'm not sure about that conclusion. Here's my guess:

The nodes modifier settings properties are dynamic IDProperties rather than regular RNA pointer properties
That means they don't have the builtin "type" information, like which IDs to look for in search lists.
In the modifier panel they are drawn with uiItemPointerR (prop_search in Python) to avoid this problem
Without that information they are disabled somewhere in the drawing process.

I remember that last part from investigating this when writing the code to display them in the modifier before, but I didn't actually see it when stepping through the code this time. (It's easy to miss though).
I was hoping the IDProperty UI data refactor in D9697 might give us a better way to tell the UI what ID type to show in search lists. We'll see, not sure yet.

I'm not sure about that conclusion. Here's my guess: - The nodes modifier settings properties are dynamic IDProperties rather than regular RNA pointer properties - That means they don't have the builtin "type" information, like which IDs to look for in search lists. - In the modifier panel they are drawn with `uiItemPointerR` (`prop_search` in Python) to avoid this problem - Without that information they are disabled somewhere in the drawing process. I remember that last part from investigating this when writing the code to display them in the modifier before, but I didn't actually see it when stepping through the code this time. (It's easy to miss though). I was hoping the IDProperty UI data refactor in [D9697](https://archive.blender.org/developer/D9697) might give us a better way to tell the UI what ID type to show in search lists. We'll see, not sure yet.

Jacques Lucke commented

2021-07-23 12:45:56 +02:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2021-07-23 12:45:56 +02:00

Just to make more explicit what Hans already said. This problem can be worked around in Python by using prop_search. More specifically layout.prop_search(mod, f'["{prop_id}"]', bpy.data, "collections", text=name). Obviously "collections" should be repaced with "objects" for object sockets.

Just to make more explicit what Hans already said. This problem can be worked around in Python by using `prop_search`. More specifically `layout.prop_search(mod, f'["{prop_id}"]', bpy.data, "collections", text=name)`. Obviously `"collections"` should be repaced with `"objects"` for object sockets.

Antti Tikka commented

2021-08-01 23:00:44 +02:00

@JacquesLucke Thanks for the workaround!

Hans Goudey commented

2021-11-09 21:58:56 +01:00

Normally I'd close this, since I think in this case there is no real bug, all of the involved code is working as expected. But keeping this around as a known issue might help in case someone else runs into this.

We were discussing changing the way geometry nodes inputs are stored. If we do that, there's a chance there could be an API for drawing the input.

If another developer would prefer to close this issue, that's okay for me.

Normally I'd close this, since I think in this case there is no real bug, all of the involved code is working as expected. But keeping this around as a known issue might help in case someone else runs into this. We were discussing changing the way geometry nodes inputs are stored. If we do that, there's a chance there could be an API for drawing the input. If another developer would prefer to close this issue, that's okay for me.

Philipp Oeser removed the

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Python API: Geometry Nodes object and collection inputs appear disabled in custom panel #89876