2.9 bug on objects: user > 1?

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#1

Hi all !

I come here with this:
user_bug.zip (1.4 MB)

This file comes from 2.9.1

It contains only 1 object and many meshes… (???)

1st, have a look at the object. You’ll notice i has 2 users. what da f*ck ???

2users
2users1276×969 216 KB

2nd, this scene, though it is correct, contains useless ( and unused ) meshes !
Look at this:

WTF_useless_meshes
WTF_useless_meshes1265×963 215 KB

What are those ( previously deleted ) meshes doing here ???
is this a normal 2.9 feature ? ( lol like many others :stuck_out_tongue: ) or some kind of bug ?

Can anybody tell me more about this ?

On blender side, this seems to be not a problem: blender works fine with 10MB of useless garbage saved in file and all is transparent.
But on a more professional app ( hehe sry for that you dev guyz :stuck_out_tongue: ) like unity3D this makes a mess and prevents the .blend ( and even the .fbx ) to be imported.

The whole blend has to be recreated from scratch with importing all objects 1 by one !

One a one scene object it’s no prob but when you have hundreds of objects this is hell !!!

Please help on this ! and if it come to be a bug, i’ll file a report on the dev website.

Happy blending !

#2

well, it’s got me stumped. there appear to be several orphaned objects, which use these geometries, but they don’t look like they belong to any scene:

image

(outliner set to “blender file”)

You can delete these orphaned objects manually in the outliner, though looking through the known issues I didn’t find anything like this, so perhaps (unless someone else here knows something) you could write up how you ended up in that state and leave a bug report at developer.blender.org

#3

Thanks a lot @stuebinm for taking time to look a this :slight_smile:

Yes there are some kinda orphans and they appear to be no problem at all for blender as blender works fine with this.

On this .blend you can easily notice what the unexpected objects and meshes are, but on my scene i got more than 100 objects and meshes. And without a way to locate orphans/bugged objects i’m kinda stuck !
And this thing, though it make no problem for blender to work fine, prevents my target app ( unity3D ) from importing the objects.

I’ll wait for some other ppl info about this and if you got any idea… please write it here :wink:

happy blending !

#4

There’s a weird custom property on that object (on all of them, in fact), which stores a self-reference. Which suggests some add-on might’ve done something horribly wrong.

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#5

Run this on your actual file:

import bpy

col = bpy.data.collections.new("Garbage")

scene = bpy.context.scene

scene.collection.children.link(col)

for o in bpy.data.objects:
    if 'parent' in o.keys():
        col.objects.link(o)
        del o['parent']

It’s a one-shot script, it’ll fail if you try to run it multiple times. It should create a new collection in your scene and put all such objects in it, also removing that strange self-reference from them.

#6

Hi @Stan_Pancakes !

Nice to see you around here :smiley:

You just confirm my thoughts: something is kinda messed-up. But…
The thing is that i got no addon installed at all :face_with_raised_eyebrow:
my 2.9.1 is as pure as possible; just like it was at the install time.

I gonna give a try to your lil script this afternoon and see wether it solves my problem :slight_smile:

What i can say it that those self referencing objects were created from one object from wich i took a face, separated it and edited it or merged it with another object.

The bad thing is that i didn’t manage to reproduce this weird bug.
I’ll try again with various actions just to see.

At last but mebe not least i have to mention that this scene was created with 2.79 and then edited with 2.9.1 ( wich is now my standard blender version ).

happy blending ! :smiley:

EDIT:
WOWOWOWOOOO :cold_face: hmmmm i think i got an idea on how to reproduce the bug :stuck_out_tongue:

I got to go now but i’ll be back this afternoon with more info :smiley:
I suspect a parenting problem :stuck_out_tongue:

happy blending !

#7

You too, @pitibonom, you too :slight_smile: I’m on and off months at a time. Hopefully for now I’ll stick around for a while.

If that problem is indeed not an add-on’s doing then this definitely needs to be brought to the devs’ attention. Be awesome if you manage to figure out what’s causing this.

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#8

YAY !!!

I think i got it !!!
As i thought it’s about parenting objects…

Now i have to reproduce the thing with clean blender file, cube and sphere objects…
I’ll post more here soon :stuck_out_tongue:

happy blending !

#9

perfect :slight_smile:

I finally found the thing @Stan_Pancakes :slight_smile:

I made a small vid for showing the thing:

I confess this appears to be a misuse of blender.
I can believe blender devs didn’t prevent stupid users ( like me ) from doing stupid things. I think i did it by error but i did it. and this messed up my scene.
at the 0:11 time, you see in the vid the parenting of the cube to itself…

Reproducing the thing is quite easy :slight_smile:
new scene
create cube
create sphere
select sphere then cube so that both are selected and cube is the active obj
parent with CTRL+P
select the cube
open relations tab
click on probe in parent fiel and select the cube

here you see ‘no parenting done’ ( wich is normal ) but the cube obj now have 2 users !!!

select the cube
hit ‘Suppr’ key
the cube disappears but the sphere parent seems ti still be here
and the cube data is still present in the blender file tab of the outliner.

This scene with deleted cube cannot be imported into unity3D.

However, blender still works like a charm as if nothing was wrong :slight_smile:

Hope you like it :stuck_out_tongue:

Happy blending !

EDIT:
ahahaha :rofl: sorry fro the green vid !!! it comes from the webm ( the forum don’t show MP4s ) coming itself from a gif capture app… :confused:
reminds me the old days when we were working on autocad on green displays :stuck_out_tongue:

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#10

Wow. Thanks, I’ll relay that to the tracker.

PS You don’t really need the sphere, the eyedropper alone on the default cube already does this. Technically yes, it’s shouldn’t break anything (in Blender, at least), but it does mean that objects stay zombies forever because they hold a reference to themselves.

#11

my pleasure @Stan_Pancakes !
I use to rumble about blender but i too rarely help on problems that i can help solving ^^
And am glad i can do it to make blender better :wink:

Thanks a lot for relaying this to the tracker :slight_smile:

Okay for the sphere. i thought about it but just wanted to show as fast as possible the way i found correct to reproduce the bug.

This is a good day :smiley: now i can go back to my cathedral modeling :slight_smile:

Thanks again @Stan_Pancakes !
have a nice day and happy blending !

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