Object modes are not loaded correctly in inactive scenes #91243

New Issue

Falk David · 2021-09-07T17:06:26+02:00

Falk David commented

2021-09-07 17:06:26 +02:00

System Information
Operating system: Linux-5.11.0-7633-generic-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.57.02

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-09-07 08:18, hash: 8cc3d2d6f5
Broken: 2.93 LTS
Broken: 2.83 LTS
Worked: ?

Short description of error
When loading a .blend file with objects in another scene, the modes for these objects are not initialized correctly. The objects will be reset to object mode.
This affects all object types and all modes, except for (obviously) object mode and, interestingly, pose mode for armatures.

Exact steps for others to reproduce the error

Open Blender and create a full copy of the current scene.
Switch to the newly created scene, select the cube and go to e.g. sculpt mode.
Go back to the other scene, select the lamp, then save the file.
Reopen the file and go to the second scene.

The cube is in object mode, not sculpt mode.

If you save the file without selecting the lamp, the cube is in sculpt mode, but the toolsystem is not initialized (e.g. no cursor appears and the toolbar is empty). This also triggers and assert in debug builds.
BLI_assert failed: source/blender/windowmanager/intern/wm_toolsystem.c:86, WM_toolsystem_ref_from_context(), at 'tref == area->runtime.tool'

Investigation

I was digging into this issue because of this report: #89514. Here is what I found:
The core issue is happening in blender/source/blender/editors/util/ed_util.c:86 when ED_editors_init is called (from wm_file_read_post "updates to make after reading a file").
This function is supposed to enter the different modes for the objects. (Note that this is really important for multi-edit and multi-pose to work. All the objects need to be checked against the active object to also enter that mode.) Here is a summary of the structure of that function:

void ED_editors_init(bContext *C)
{
  ...
  Object *obact = CTX_data_active_object(C);
  for (Object *ob = bmain->objects.first; ob; ob = ob->id.next) {
    int mode = ob->mode;
    if (mode == OB_MODE_OBJECT) {
      continue;
    }
    ...
    ob->mode = OB_MODE_OBJECT;
    if (obact && (ob->type == obact->type) && ...) {
       // Do the mode switching
    }
  }
  ...
}

The first issue seems to be that this loop iterates over all the objects (that are not in object mode) in the entire file. This is a problem, because we are comparing the mode of ob to obact which is the active object in the current scene. So this part of the code only really makes sense if obact is the active object in the scene that ob is also in.
Additionally we are overwriting the mode of that object ob and resetting it to object mode.

**System Information** Operating system: Linux-5.11.0-7633-generic-x86_64-with-glibc2.33 64 Bits Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 470.57.02 **Blender Version** Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-09-07 08:18, hash: `8cc3d2d6f5` Broken: 2.93 LTS Broken: 2.83 LTS Worked: ? **Short description of error** When loading a `.blend` file with objects in another scene, the modes for these objects are not initialized correctly. The objects will be reset to object mode. This affects *all* object types and all modes, *except* for (obviously) object mode and, interestingly, pose mode for armatures. **Exact steps for others to reproduce the error** - Open Blender and create a full copy of the current scene. - Switch to the newly created scene, select the cube and go to e.g. sculpt mode. - Go back to the other scene, **select the lamp**, then save the file. - Reopen the file and go to the second scene. # The cube is in object mode, not sculpt mode. If you save the file without selecting the lamp, the cube is in sculpt mode, but the toolsystem is not initialized (e.g. no cursor appears and the toolbar is empty). This also triggers and assert in debug builds. `BLI_assert failed: source/blender/windowmanager/intern/wm_toolsystem.c:86, WM_toolsystem_ref_from_context(), at 'tref == area->runtime.tool'` **Investigation** I was digging into this issue because of this report: #89514. Here is what I found: The core issue is happening in `blender/source/blender/editors/util/ed_util.c:86` when `ED_editors_init` is called (from `wm_file_read_post` "updates to make after reading a file"). This function is supposed to enter the different modes for the objects. (Note that this is really important for multi-edit and multi-pose to work. All the objects need to be checked against the active object to also enter that mode.) Here is a summary of the structure of that function: ``` void ED_editors_init(bContext *C) { ... Object *obact = CTX_data_active_object(C); for (Object *ob = bmain->objects.first; ob; ob = ob->id.next) { int mode = ob->mode; if (mode == OB_MODE_OBJECT) { continue; } ... ob->mode = OB_MODE_OBJECT; if (obact && (ob->type == obact->type) && ...) { // Do the mode switching } } ... } ``` The first issue seems to be that this loop iterates over all the objects (that are not in object mode) in the entire file. This is a problem, because we are comparing the mode of `ob` to `obact` which is the active object *in the current scene*. So this part of the code only really makes sense if `obact` is the active object in the scene that `ob` is also in. Additionally we are overwriting the mode of that object `ob` and resetting it to object mode.

Falk David commented

2021-09-07 17:06:26 +02:00

Added subscriber: @filedescriptor

Philipp Oeser commented

2021-09-30 10:11:28 +02:00

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

Bastien Montagne commented

2021-10-07 15:44:15 +02:00

Added subscribers: @ideasman42, @brecht, @mont29

Bastien Montagne commented

2021-10-07 15:44:15 +02:00

Wouldn't mind @ideasman42 or @brecht advice on this, but I would say always switching back objects in inactive scenes to Object mode is a decent compromise of safety/simplicity here... And then only do the mode switching if the object is in current active scene?

Otherwise in case some objects are instantiated in several scenes at the same time, correctly dealing with this can become fairly tricky and error prone am afraid.

Wouldn't mind @ideasman42 or @brecht advice on this, but I would say always switching back objects in inactive scenes to `Object` mode is a decent compromise of safety/simplicity here... And then only do the mode switching if the object is in current active scene? Otherwise in case some objects are instantiated in several scenes at the same time, correctly dealing with this can become fairly tricky and error prone am afraid.

Brecht Van Lommel commented

2021-10-11 19:55:51 +02:00

It would be nice to preserve the modes in other scenes, but it seems complicated and I would not consider that a bug. Resetting to object mode seems reasonable to me.

blender-admin commented

2021-10-20 12:50:39 +02:00

This issue was referenced by dfb193f634

This issue was referenced by dfb193f634bf2d4b6a28b458d7d23b79bcd45633

Bastien Montagne commented

2021-10-20 14:59:48 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Bastien Montagne closed this issue

2021-10-20 14:59:48 +02:00

Bastien Montagne self-assigned this 2021-10-20 14:59:48 +02:00

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Object modes are not loaded correctly in inactive scenes #91243

The cube is in object mode, not sculpt mode.