Joining objects results in an error #112218

New Issue

Robin-Hogerhuis · 2023-09-11T09:26:52+02:00

Robin-Hogerhuis commented

2023-09-11 09:26:52 +02:00

System Information
Operating system: Windows 10 Enterprise
Graphics card: NVIDIA Quadro K600 and NVIDIA GeForce GT 610 (for two monitor setup)

Blender Version
Broken: 3.5.1, hash: e1ccd9d4a1

Short description of error
RuntimeError: Operator bpy.ops.object.join.poll() failed, context is incorrect

Exact steps for others to reproduce the error
I execute my python file from Visual Studio Code to Blender. I have followed this tutorial to accomplish this: https://www.youtube.com/watch?v=YUytEtaVrrc. I get the error when trying to join all meshes of my imported gltf object.

In specific
I'm trying to join multiple meshes of my imported GLTF object. This object consists of multiple meshes/parts and I want to join them via the python API to know the complete dimensions of the joined object. When trying to do this with code it didn't work and I got the above message. To test further I tried to join all objects in my scene as a simpler use case. But, I still got the same error. Thirdly, I tried to join the objects in Blender directly by using 'a' -> 'ctrl + j'. What I found are some inconsistencies. When trying it, sometimes it works and sometimes it doesn't. I often get it working when deselecting and selecting everything and trying it again until it works. See code for more specifics.

Goal
I'm trying to join all meshes within my loaded GLTF object. But, it seems that there is a bug within Blender that stops me from doing this.

Code

def load_gltf_object(filepath: str) -> None:
   # Import gltf object 
   bpy.ops.import_scene.gltf(filepath=filepath)

   # Select all objects for a simpler use case 
   bpy.ops.object.select_all(action='SELECT')

   # Join all objects 
   bpy.ops.object.join()

load_gltf_object(filepath)

**System Information** Operating system: Windows 10 Enterprise Graphics card: NVIDIA Quadro K600 and NVIDIA GeForce GT 610 (for two monitor setup) **Blender Version** Broken: 3.5.1, hash: e1ccd9d4a1d3 **Short description of error** `RuntimeError: Operator bpy.ops.object.join.poll() failed, context is incorrect` **Exact steps for others to reproduce the error** I execute my python file from Visual Studio Code to Blender. I have followed this tutorial to accomplish this: https://www.youtube.com/watch?v=YUytEtaVrrc. I get the error when trying to join all meshes of my imported gltf object. **In specific** I'm trying to join multiple meshes of my imported GLTF object. This object consists of multiple meshes/parts and I want to join them via the python API to know the complete dimensions of the joined object. When trying to do this with code it didn't work and I got the above message. To test further I tried to join all objects in my scene as a simpler use case. But, I still got the same error. Thirdly, I tried to join the objects in Blender directly by using 'a' -> 'ctrl + j'. What I found are some inconsistencies. When trying it, sometimes it works and sometimes it doesn't. I often get it working when deselecting and selecting everything and trying it again until it works. See code for more specifics. **Goal** I'm trying to join all meshes within my loaded GLTF object. But, it seems that there is a bug within Blender that stops me from doing this. **Code** ```python def load_gltf_object(filepath: str) -> None: # Import gltf object bpy.ops.import_scene.gltf(filepath=filepath) # Select all objects for a simpler use case bpy.ops.object.select_all(action='SELECT') # Join all objects bpy.ops.object.join() load_gltf_object(filepath) ```

joing_objects_error.png

62 KiB

object_with_multiple_meshes.png

1.3 MiB

Robin-Hogerhuis added the

labels 2023-09-11 09:26:53 +02:00

YimingWu commented

2023-09-11 10:07:06 +02:00

object.join requires there's at least an active window and screen, so you probably need to find an active screen and use it as a context override. Try doing this:

wnd=bpy.data.window_managers[0].windows[0]
scr=bpy.data.screens[0]
with bpy.context.temp_override(window=wnd,screen=scr):
    bpy.ops.object.join()

After some digging I don't think I have seen any of the window/screen being referenced in the join function, nor does any of the called ones inside there, so I'm not quite sure why that's needed. The related bits in object_join_poll doesn't seem to have changed in at least 4 years, I think it's technically safe to not require a window and screen.

`object.join` requires there's at least an active window and screen, so you probably need to find an active screen and use it as a context override. Try doing this: ``` wnd=bpy.data.window_managers[0].windows[0] scr=bpy.data.screens[0] with bpy.context.temp_override(window=wnd,screen=scr): bpy.ops.object.join() ``` After some digging I don't think I have seen any of the window/screen being referenced in the join function, nor does any of the called ones inside there, so I'm not quite sure why that's needed. The related bits in `object_join_poll` doesn't seem to have changed in at least 4 years, I think it's technically safe to not require a window and screen.

YimingWu added

Module

Modeling

Status

Needs Info from Developers

and removed

Status

Needs Triage

labels 2023-09-11 10:07:24 +02:00

Philipp Oeser commented

2023-09-11 10:09:50 +02:00

Looks like there are Empties involved in the join operation (e.g. the Sketchfab nmodel object)

It would be normal that the operation is cancelled in this case
So to get that out of the way, does it work for you if you substitute

bpy.ops.object.select_all(action='SELECT')

with

bpy.ops.object.select_by_type(type='MESH') ?

Looks like there are Empties involved in the join operation (e.g. the `Sketchfab nmodel` object) It would be normal that the operation is cancelled in this case So to get that out of the way, does it work for you if you substitute `bpy.ops.object.select_all(action='SELECT')` with `bpy.ops.object.select_by_type(type='MESH')` ?

Robin-Hogerhuis commented

2023-09-11 10:59:02 +02:00

@ChengduLittleA , Thank you for your reply. I have tried to manually set the active window and screen with your code, but the error still occurs.

@lichtwerk. Also thank you for your reply. I have tried it before by only selecting the meshes indeed, but no luck then. But I tried it again with your code and still got the same error.

Also I have tried both your ideas combined for testing sake but still received the same error. To maybe replicate the same error this is the object I'm currently testing with (see uploaded file)

@ChengduLittleA , Thank you for your reply. I have tried to manually set the active window and screen with your code, but the error still occurs. @lichtwerk. Also thank you for your reply. I have tried it before by only selecting the meshes indeed, but no luck then. But I tried it again with your code and still got the same error. Also I have tried both your ideas combined for testing sake but still received the same error. To maybe replicate the same error this is the object I'm currently testing with (see uploaded file)

plant (11).zip

4.9 MiB

YimingWu commented

2023-09-11 11:37:13 +02:00

From testing your file and script, it's likely that you don't have an active object as mesh at the time of importing.

Thus you will need to manually find and assign an active_object as context override as well:

def load_gltf_object(filepath: str) -> None:
    # Import gltf object 
    bpy.ops.import_scene.gltf(filepath=filepath)

    # Select all objects for a simpler use case 
    bpy.ops.object.select_all(action='SELECT')

    # Join all objects 
    wnd=bpy.data.window_managers[0].windows[0]
    scr=bpy.data.screens[0]
    obj=None
    for ob in bpy.data.objects:
        if ob.type=='MESH':
            obj=ob
            break
    if obj is None:
        return
    
    with bpy.context.temp_override(window=wnd,screen=scr,active_object=obj):
        bpy.ops.object.join()

It should not require window and screen to be present, I will make a patch to get rid of that part.

From testing your file and script, it's likely that you don't have an active object as mesh at the time of importing. Thus you will need to manually find and assign an `active_object` as context override as well: ``` def load_gltf_object(filepath: str) -> None: # Import gltf object bpy.ops.import_scene.gltf(filepath=filepath) # Select all objects for a simpler use case bpy.ops.object.select_all(action='SELECT') # Join all objects wnd=bpy.data.window_managers[0].windows[0] scr=bpy.data.screens[0] obj=None for ob in bpy.data.objects: if ob.type=='MESH': obj=ob break if obj is None: return with bpy.context.temp_override(window=wnd,screen=scr,active_object=obj): bpy.ops.object.join() ``` It _should_ not require window and screen to be present, I will make a patch to get rid of that part.

👍 1 🎉 1

Robin-Hogerhuis commented

2023-09-11 11:49:42 +02:00

@ChengduLittleA , thank you very much. I tested it and it works!!

YimingWu referenced a pull request that will close this issue

2023-09-11 15:53:19 +02:00

Fix #112218: Do not require screen in `object_join_poll` #112244

YimingWu referenced this issue from a commit

2023-09-11 15:54:35 +02:00

Fix #112218: Do not require screen in `object_join_poll`

YimingWu closed this issue

2023-09-11 15:54:37 +02:00