Crash on Append #51211

New Issue

Konstantins Visnevskis · 2017-04-14T16:29:40+02:00

2017-04-14 16:29:40 +02:00

System Information
Win8.1x64, 3x gtx580

Blender Version
2.78c

Short description of error
Blender crashes when trying to append particular object.
Some objects deleted before saving are still saved and shown in the Append for no apparent reason.

Some of actions done before included:
making shaders referring to coordinates of other objects,
using modifiers referring to coordinates of other objects on those objects,
linking, deleting, making single user, separately referring and referral objects between the scenes, including aforementioned objects,
duplicating scenes.

Exact steps for others to reproduce the error

Open blender,
Try to append the scene or object "clouds.base.001" from attached file.
import-ob-e2.blend

**System Information** Win8.1x64, 3x gtx580 **Blender Version** 2.78c **Short description of error** Blender crashes when trying to append particular object. Some objects deleted before saving are still saved and shown in the Append for no apparent reason. Some of actions done before included: making shaders referring to coordinates of other objects, using modifiers referring to coordinates of other objects on those objects, linking, deleting, making single user, separately referring and referral objects between the scenes, including aforementioned objects, duplicating scenes. **Exact steps for others to reproduce the error** - Open blender, - Try to append the scene or object "clouds.base.001" from attached file. [import-ob-e2.blend](https://archive.blender.org/developer/F545406/import-ob-e2.blend)

Konstantins Visnevskis commented

2017-04-14 16:29:40 +02:00

Changed status to: 'Open'

Konstantins Visnevskis commented

2017-04-14 16:29:40 +02:00

Added subscriber: @KonstantinsVisnevskis

Aaron Carlisle commented

2017-04-14 18:06:04 +02:00

Added subscriber: @Blendify

Aaron Carlisle commented

2017-04-14 18:06:04 +02:00

I cannot confirm the issue, some things to try:

Start blender with factory settings
Try a daily build from https://builder.blender.org/download/

I cannot confirm the issue, some things to try: - Start blender with factory settings - Try a daily build from https://builder.blender.org/download/

Konstantins Visnevskis commented

2017-04-14 21:47:06 +02:00

Indeed. On linux, the daily build works fine, the 2.78c crashes.
Still though - daily build keeps non-linked objects present in the file after saving.

Indeed. On linux, the daily build works fine, the 2.78c crashes. Still though - daily build keeps non-linked objects present in the file after saving.

Bastien Montagne was assigned by Aaron Carlisle

2017-04-14 21:50:33 +02:00

Bastien Montagne commented

2017-05-23 14:20:24 +02:00

Don’t understand what is the issue here, when I append clouds.base.001 I get three other objects, because those are used by node material of appended one. Nothing fancy here.

Please be more specific about what happens for you, what result you would expect, etc.

Don’t understand what is the issue here, when I append `clouds.base.001` I get three other objects, because those are used by node material of appended one. Nothing fancy here. Please be more specific about what happens for you, what result you would expect, etc.

Konstantins Visnevskis commented

2017-05-23 22:13:51 +02:00

Open the attached file and re-save it. The file has only one object present (as seen in the viewport and outliner), the rest were deleted. But a bunch of objects remain saved in the file as can be seen when trying to append or browsing data blocks.

Bastien Montagne commented

2017-05-24 10:50:56 +02:00

All those objects are still in use, either by a group or a nodetree (type for k, v in D.user_map(D.objects).items(): print(k, v) in the python console to see all objetcs' users).

So all object being kept across save/Reload is totally normal. Not sure how you deleted your objects from scene, but issue is/was probably there, so that’s what we'd need to be able to reproduce (how you got to such a file with bunch of objects deleted from scenes but still used by other data-blocks).

All those objects are still in use, either by a group or a nodetree (type `for k, v in D.user_map(D.objects).items(): print(k, v)` in the python console to see all objetcs' users). So all object being kept across save/Reload is totally normal. Not sure how you deleted your objects from scene, but issue is/was probably there, so that’s what we'd need to be able to reproduce (how you got to such a file with bunch of objects deleted from scenes but still used by other data-blocks).

Konstantins Visnevskis commented

2017-05-24 14:08:38 +02:00

Maybe got it -

When a texture coordinate shader node refers to an object and the scene is made a full copy of, the material itself gets duplicated, but the nodes still refer to an object in a previous scene, not the duplicate.
When the original scene gets deleted in such scenario (or sometimes, not yet sure what it correlates with, when the object is pointed from another scene directly) for some reason, the object a texture coordinate node was referring to remains. And it sometimes (again, not yet tested when) remains after multiple re-savings even if the scene is completely empty.

Maybe got it - 1. When a texture coordinate shader node refers to an object and the scene is made a full copy of, the material itself gets duplicated, but the nodes still refer to an object in a previous scene, not the duplicate. 2. When the original scene gets deleted in such scenario (or sometimes, not yet sure what it correlates with, when the object is pointed from another scene directly) for some reason, the object a texture coordinate node was referring to remains. And it sometimes (again, not yet tested when) remains after multiple re-savings even if the scene is completely empty.

Bastien Montagne commented

2017-05-24 14:21:54 +02:00

Added subscriber: @ideasman42

Bastien Montagne commented

2017-05-24 14:21:54 +02:00

Well… there is no bug here really… Nodes are refcounting users of their ID, which means if a node uses and object, it increases its user count, which hence remains >= 1 even when object is fully deleted from scene. So obviously that object won't be discarded on save, no matter how many times you save it - not until all nodes using it get removed.

We could do same kind of hacks as with groups to ensure an object used in nodes cannot be deleted from all scenes - but am starting to be very annoyed by this Object ID exception, think real TODO here is to provide better ID management access for user, and to allow them to re-instantiate an object in a scene from scratch, and to allow them to properly delete them even when not instantiated in any scene (this should be doable in Outliner already), etc.

Unless @Sergey or @ideasman42 have something to add here, will close this report, again this is expected behavior in current code, so that’s (known) design task, not a bug.

Well… there is no bug here really… Nodes are refcounting users of their ID, which means if a node uses and object, it increases its user count, which hence remains >= 1 even when object is fully deleted from scene. So obviously that object won't be discarded on save, no matter how many times you save it - not until all nodes using it get removed. We *could* do same kind of hacks as with groups to ensure an object used in nodes cannot be deleted from all scenes - but am starting to be **very** annoyed by this Object ID exception, think real TODO here is to provide better ID management access for user, and to allow them to re-instantiate an object in a scene from scratch, and to allow them to properly delete them even when not instantiated in any scene (this should be doable in Outliner already), etc. Unless @Sergey or @ideasman42 have something to add here, will close this report, again this is expected behavior in current code, so that’s (known) design task, not a bug.

Bastien Montagne commented

2017-05-24 14:28:44 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2017-05-24 14:50:04 +02:00

Think it is more important to prevent loosing your data here. Having some editor which visualized what IDs are used for would help here, but it's out of the scope of bug tracker. So it is indeed a TODO.

Bastien Montagne commented

2017-05-24 14:51:07 +02:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2017-05-24 14:51:07 +02:00

Konstantins Visnevskis commented

2017-05-24 15:52:27 +02:00

"When a texture coordinate shader node refers to an object and the scene is made a full copy of, the material itself gets duplicated, but the nodes still refer to an object in a previous scene, not the duplicate."
Isn't this a bug?
Mentioned TODO ideas are good and I understand (albeit loosely) the mechanism behind the object remaining, but I didn't suggest that's necessarily the problem. What seems obvious from users perspective however is that when an object is deleted together with a whole scene, it should disappear from all the shader nodes, modifiers etc. referring to it, just like when it is deleted individually. Which, while not a global solution for all linking problems, like already existing orphaned objects, would stop producing them at least in this case.

1. "When a texture coordinate shader node refers to an object and the scene is made a full copy of, the material itself gets duplicated, but the nodes still refer to an object in a previous scene, not the duplicate." Isn't this a bug? 2. Mentioned TODO ideas are good and I understand (albeit loosely) the mechanism behind the object remaining, but I didn't suggest that's necessarily the problem. What seems obvious from users perspective however is that when an object is deleted together with a whole scene, it should disappear from all the shader nodes, modifiers etc. referring to it, just like when it is deleted individually. Which, while not a global solution for all linking problems, like already existing orphaned objects, would stop producing them at least in this case.

Konstantins Visnevskis commented

2017-05-25 17:04:07 +02:00

Ok, sorry - this is a mess and rather unrelated to initial report. I'll try to make it to the point:
https://developer.blender.org/T51624
https://developer.blender.org/T51625

Ok, sorry - this is a mess and rather unrelated to initial report. I'll try to make it to the point: https://developer.blender.org/T51624 https://developer.blender.org/T51625

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Crash on Append #51211