Python UI inconsistent with the documentation #113732

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Ethical Vegan · 2023-10-15T02:35:15+02:00

Ethical Vegan commented

2023-10-15 02:35:15 +02:00

Blender Version
Broken: 3.6.1
Worked: NA

When baking a texture using Python, the following code correctly bakes the normal map:
import bpy
bpy.ops.object.bake(type='NORMAL')

On the other hand, the following does not work:
import bpy
bpy.context.scene.cycles.bake_type = 'NORMAL'
bpy.ops.object.bake()

But as you can see in the image, the interface is telling us to write "bpy.context.scene.cycles.bake_type = 'NORMAL'"

**Blender Version** Broken: 3.6.1 Worked: NA When baking a texture using Python, the following code correctly bakes the normal map: import bpy bpy.ops.object.bake(type='NORMAL') On the other hand, the following does not work: import bpy bpy.context.scene.cycles.bake_type = 'NORMAL' bpy.ops.object.bake() But as you can see in the image, the interface is telling us to write "bpy.context.scene.cycles.bake_type = 'NORMAL'"

Python UI.png

375 KiB

Ethical Vegan added the

labels 2023-10-15 02:35:15 +02:00

Thomas Barlow commented

2023-10-15 05:29:20 +02:00

Calling bpy.ops.object.bake() will use the default value of its type argument which is 'COMBINED'.

Setting scene.cycles.bake_type changes the type argument of the bpy.ops.object.bake operator that is displayed in the UI: https://projects.blender.org/blender/blender/src/branch/blender-v3.6-release/intern/cycles/blender/addon/ui.py#L1928

Hovering the mouse over with Bake button shows the type argument:

No bug here as far as I can tell.

Calling `bpy.ops.object.bake()` will use the default value of its `type` argument which is `'COMBINED'`. Setting `scene.cycles.bake_type` changes the `type` argument of the `bpy.ops.object.bake` operator that is displayed in the UI: https://projects.blender.org/blender/blender/src/branch/blender-v3.6-release/intern/cycles/blender/addon/ui.py#L1928 Hovering the mouse over with Bake button shows the `type` argument: ![image](/attachments/6dae800e-f989-4843-b5c1-2bde65b446ae) No bug here as far as I can tell.

image.png

8.2 KiB

Ethical Vegan commented

2023-10-15 19:07:17 +02:00

I think I understand what the problem is, let me explain.
I should have mentioned that "type" is the only parameter that works like that. For all the other parameters, modifying what is displayed in the UI affects bpy.ops.object.bake(). In the documentation https://docs.blender.org/api/current/bpy.ops.object.html, we have the following:

bpy.ops.object.bake(type='COMBINED', pass_filter={}, filepath='', width=512, height=512, margin=16, margin_type='EXTEND', use_selected_to_active=False, max_ray_distance=0.0, cage_extrusion=0.0, cage_object='', normal_space='TANGENT', normal_r='POS_X', normal_g='POS_Y', normal_b='POS_Z', target='IMAGE_TEXTURES', save_mode='INTERNAL', use_clear=False, use_cage=False, use_split_materials=False, use_automatic_name=False, uv_layer='')

In the description of the parameters, nothing tells us that the "type" parameter works differently than all others.

Write now we have to write the following:
import bpy
bpy.context.scene.cycles.bake_type = 'NORMAL'
bpy.context.scene.render.bake.normal_g = 'NEG_Y'
bpy.context.scene.render.bake.use_selected_to_active = True

bpy.ops.object.bake(type=bpy.context.scene.cycles.bake_type)

For example, "bpy.context.scene.render.bake.normal_g" modifies the UI dropdown, and it does not need to be written again inside bpy.ops.object.bake().
The paramater "type" is the only one that needs to be inside bpy.ops.object.bake().

Shouldn't it be "bpy.context.scene.render.bake_type" instead of "bpy.context.scene.cycles.bake_type"?
So "render" instead of "cycles"?

"bpy.context.scene.cycles" I think was used in older Blender versions, as you can see here: https://docs.blender.org/api/2.80/bpy.types.CyclesRenderSettings.html

I think I understand what the problem is, let me explain. I should have mentioned that "type" is the only parameter that works like that. For all the other parameters, modifying what is displayed in the UI affects bpy.ops.object.bake(). In the documentation https://docs.blender.org/api/current/bpy.ops.object.html, we have the following: bpy.ops.object.bake(type='COMBINED', pass_filter={}, filepath='', width=512, height=512, margin=16, margin_type='EXTEND', use_selected_to_active=False, max_ray_distance=0.0, cage_extrusion=0.0, cage_object='', normal_space='TANGENT', normal_r='POS_X', normal_g='POS_Y', normal_b='POS_Z', target='IMAGE_TEXTURES', save_mode='INTERNAL', use_clear=False, use_cage=False, use_split_materials=False, use_automatic_name=False, uv_layer='') In the description of the parameters, nothing tells us that the "type" parameter works differently than all others. Write now we have to write the following: import bpy bpy.context.scene.cycles.bake_type = 'NORMAL' bpy.context.scene.render.bake.normal_g = 'NEG_Y' bpy.context.scene.render.bake.use_selected_to_active = True bpy.ops.object.bake(type=bpy.context.scene.cycles.bake_type) For example, "bpy.context.scene.render.bake.normal_g" modifies the UI dropdown, and it does not need to be written again inside bpy.ops.object.bake(). The paramater "type" is the only one that needs to be inside bpy.ops.object.bake(). Shouldn't it be "bpy.context.scene.render.bake_type" instead of "bpy.context.scene.cycles.bake_type"? So "render" instead of "cycles"? "bpy.context.scene.cycles" I think was used in older Blender versions, as you can see here: https://docs.blender.org/api/2.80/bpy.types.CyclesRenderSettings.html

Thomas Barlow commented

2023-10-15 20:27:34 +02:00

Hmm, I wouldn't have expected that calling bpy.ops.object.bake() would use any of the bpy.context.scene.render.bake.normal_g and similar properties because the default execution context for Operators called from code is 'EXEC_DEFAULT' which does not call invoke functions.

Looking at the source, both the execute and invoke functions call bake_set_props(). I think it may be a bug that the execute function also calls bake_set_props().

Rather than the type argument being the argument with odd behaviour, I think it would be better to say that all the other arguments are the ones with odd behaviour because their default values are ignored and instead replaced by values from bpy.context.scene.render.bake.

Call in execute: b6131cc338/source/blender/editors/object/object_bake_api.cc (L1868)
Call in invoke: b6131cc338/source/blender/editors/object/object_bake_api.cc (L2105)

Hmm, I wouldn't have expected that calling `bpy.ops.object.bake()` would use any of the `bpy.context.scene.render.bake.normal_g` and similar properties because the default execution context for Operators called from code is `'EXEC_DEFAULT'` which does not call `invoke` functions. Looking at the source, both the `execute` and `invoke` functions call `bake_set_props()`. I think it may be a bug that the `execute` function also calls `bake_set_props()`. Rather than the `type` argument being the argument with odd behaviour, I think it would be better to say that all the other arguments are the ones with odd behaviour because their default values are ignored and instead replaced by values from `bpy.context.scene.render.bake`. Call in `execute`: https://projects.blender.org/blender/blender/src/commit/b6131cc338ab05b5c59f34ae3fc174e4c45d73ba/source/blender/editors/object/object_bake_api.cc#L1868 Call in `invoke`: https://projects.blender.org/blender/blender/src/commit/b6131cc338ab05b5c59f34ae3fc174e4c45d73ba/source/blender/editors/object/object_bake_api.cc#L2105

Ethical Vegan commented

2023-10-15 20:57:47 +02:00

I agree.

And shouldn't bake_type be inside "bpy.context.scene.render" or "bpy.context.scene.render.bake" instead of "bpy.context.scene.cycles"?

Because CyclesRenderSettings is inside Blender 2.8 documentation: https://docs.blender.org/api/2.80/bpy.types.CyclesRenderSettings.html

But it is not inside Blender 3.6 documentation: https://docs.blender.org/api/current/bpy.types.html

I agree. And shouldn't bake_type be inside "bpy.context.scene.render" or "bpy.context.scene.render.bake" instead of "bpy.context.scene.cycles"? Because CyclesRenderSettings is inside Blender 2.8 documentation: https://docs.blender.org/api/2.80/bpy.types.CyclesRenderSettings.html But it is not inside Blender 3.6 documentation: https://docs.blender.org/api/current/bpy.types.html

Pratik Borhade commented

2023-10-16 11:24:41 +02:00

I think bpy.ops.object.bake() should bake with default arguments (i.e. type=combined and other default parameters)
@lichtwerk , any idea about the expected result?

I think `bpy.ops.object.bake()` should bake with default arguments (i.e. type=combined and other default parameters) @lichtwerk , any idea about the expected result?

Pratik Borhade added

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Python UI inconsistent with the documentation #113732