Group instantiation problem with mesh objects created in inactive scene. #54358

New Issue

Bill Currie · 2018-03-19T11:58:20+01:00

Bill Currie commented

2018-03-19 11:58:20 +01:00

System Information
Linux, Nvidia 1080

Blender Version
Broken: 2.79 (2018-03-15 hash 995ccf8168)

Short description of error
When a mesh object is created in an inactive scene and instantiated via group instantiation, the mesh does not show until the inactive scene is visited.

Exact steps for others to reproduce the error
In the attached scenetest.blend, hit alt-p in the text editor. The created object will be just an empty until test_scene is visited.scenetest.blend

**System Information** Linux, Nvidia 1080 **Blender Version** Broken: 2.79 (2018-03-15 hash 995ccf81688) **Short description of error** When a mesh object is created in an inactive scene and instantiated via group instantiation, the mesh does not show until the inactive scene is visited. **Exact steps for others to reproduce the error** In the attached scenetest.blend, hit alt-p in the text editor. The created object will be just an empty until test_scene is visited.[scenetest.blend](https://archive.blender.org/developer/F2463550/scenetest.blend)

Bill Currie commented

2018-03-19 11:58:20 +01:00

Added subscriber: @taniwha

Paweł Żukowski commented

2018-03-26 21:20:36 +02:00

Added subscriber: @idlecode

Philipp Oeser commented

2018-04-19 22:27:57 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2018-04-19 22:27:57 +02:00

Confirming the issue on first sight.

Before looking at this further: Is there actually a reason to not change scenes via python [to circumvent this issue?]

import bpy
from mathutils import Vector

test_verts = [
    Vector(( 1,  1,  1)),
    Vector((-1, -1,  1)),
    Vector(( 1, -1, -1)),
    Vector((-1,  1, -1)),
]
test_faces = [
    (0, 1, 2),
    (0, 2, 3),
    (0, 3, 1),
    (3, 2, 1),
]

if "test_scene" not in bpy.data.scenes:
    scene = bpy.data.scenes.new("test_scene")
else:
    scene = bpy.data.scenes["test_scene"]

bpy.context.screen.scene = scene

mesh = bpy.data.meshes.new("testmesh")
mesh.from_pydata(test_verts, [], test_faces)

obj = bpy.data.objects.new("testobj", mesh)
scene.objects.link(obj)

group = bpy.data.groups.new("test_group")
group.objects.link(obj)

bpy.context.screen.scene = bpy.data.scenes["Scene"]

iobj = bpy.data.objects.new("group_object", None)
iobj.dupli_type = 'GROUP'
iobj.dupli_group = group
bpy.context.scene.objects.link(iobj)

Confirming the issue on first sight. Before looking at this further: Is there actually a reason to **not** change scenes via python [to circumvent this issue?] ``` import bpy from mathutils import Vector test_verts = [ Vector(( 1, 1, 1)), Vector((-1, -1, 1)), Vector(( 1, -1, -1)), Vector((-1, 1, -1)), ] test_faces = [ (0, 1, 2), (0, 2, 3), (0, 3, 1), (3, 2, 1), ] if "test_scene" not in bpy.data.scenes: scene = bpy.data.scenes.new("test_scene") else: scene = bpy.data.scenes["test_scene"] bpy.context.screen.scene = scene mesh = bpy.data.meshes.new("testmesh") mesh.from_pydata(test_verts, [], test_faces) obj = bpy.data.objects.new("testobj", mesh) scene.objects.link(obj) group = bpy.data.groups.new("test_group") group.objects.link(obj) bpy.context.screen.scene = bpy.data.scenes["Scene"] iobj = bpy.data.objects.new("group_object", None) iobj.dupli_type = 'GROUP' iobj.dupli_group = group bpy.context.scene.objects.link(iobj) ```

Bill Currie commented

2018-04-26 14:42:22 +02:00

I sort of do a similar thing by creating the object in the current scene then moving it to the utility scene, but that's only because the created object may or may not be moved depending on other factors.

Of course, I could just briefly switch to the utility scene when creating the object, but that feels too hacky for me to be comfortable with it, and also I worry about the possibility that there may be other lurking issues that will need addressing anyway. That is, it seems cleaner to fix the root problem rather than just work around it.

I sort of do a similar thing by creating the object in the current scene then moving it to the utility scene, but that's only because the created object may or may not be moved depending on other factors. Of course, I could just briefly switch to the utility scene when creating the object, but that feels too hacky for me to be comfortable with it, and also I worry about the possibility that there may be other lurking issues that will need addressing anyway. That is, it seems cleaner to fix the root problem rather than just work around it.

Philipp Oeser self-assigned this 2018-04-26 15:07:41 +02:00

Philipp Oeser commented

2018-04-26 15:07:41 +02:00

OK, will have a closer look later [and shout for help if that doesnt succeed :)]

Philipp Oeser was unassigned by Dalai Felinto

2019-12-23 16:36:16 +01:00

Philipp Oeser commented

2020-01-30 13:47:27 +01:00

Changed status from 'Confirmed' to: 'Resolved'

Philipp Oeser closed this issue

2020-01-30 13:47:27 +01:00

Philipp Oeser self-assigned this 2020-01-30 13:47:27 +01:00

Philipp Oeser commented

2020-01-30 13:47:27 +01:00

Hi there (sorry this has been lying around for so long...)

I have updated the file/script to 2.8 syntax
https://wiki.blender.org/wiki/Reference/Release_Notes/2.80/Python_API/Scene_and_Object_API

scenetest_28.blend

This now seems to work just fine, the mesh does show up immediately, the inactive scene doesnt have to be visited.

So will close as resolved then (feel free though to comment again if issues persist....)

Hi there (sorry this has been lying around for so long...) I have updated the file/script to 2.8 syntax https://wiki.blender.org/wiki/Reference/Release_Notes/2.80/Python_API/Scene_and_Object_API [scenetest_28.blend](https://archive.blender.org/developer/F8313622/scenetest_28.blend) This now seems to work just fine, the mesh does show up immediately, the inactive scene doesnt have to be visited. So will close as resolved then (feel free though to comment again if issues persist....)

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Group instantiation problem with mesh objects created in inactive scene. #54358