# GLTF Export Bug: Skinning has errors
**URL:** https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744
**Category:** Bugs
**Created:** [August 28, 2020, 8:30am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744 "2020-08-28T08:30:13Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@mrlooi](https://forum.babylonjs.com/u/mrlooi)
#### Post date: [August 28, 2020, 8:30am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/1 "2020-08-28T08:30:13Z")
So I exported a GLB via BJS GLB serializer, and re-imported it back in BJS to test it. Turns out the mesh skinning has issues. I could show a video but it says “new users cannot upload attachments”
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### Author:  [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)
#### Post date: [August 28, 2020, 8:47am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/2 "2020-08-28T08:47:46Z")
I think a PG will help looking for the problem on our end.
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### Author:  [@mrlooi](https://forum.babylonjs.com/u/mrlooi)
#### Post date: [August 28, 2020, 8:53am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/3 "2020-08-28T08:53:19Z")
How should I do this then. Show a PG that loads the original mesh, then exports it as a GLB, then re-imports the newly exported GLB?
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### Author:  [@mrlooi](https://forum.babylonjs.com/u/mrlooi)
#### Post date: [August 28, 2020, 8:53am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/4 "2020-08-28T08:53:54Z")
Probably easier if I just send the mesh itself?
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### Author:  [@mrlooi](https://forum.babylonjs.com/u/mrlooi)
#### Post date: [August 28, 2020, 8:58am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/5 "2020-08-28T08:58:44Z")
Here’s the link to the “mutant.glb” btw
> **[mutant.glb](https://drive.google.com/file/d/1yqXYDk4mE_doSYV-c6l-PHdcGpm9yqHp/view?usp=sharing)**
>
> Google Drive file.
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### Author:  [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)
#### Post date: [August 28, 2020, 9:39am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/6 "2020-08-28T09:39:16Z")
A nice repro would be to host your file in a server and udpate this PG to point to it:
[https://playground.babylonjs.com/#SYQW69#391](https://playground.babylonjs.com/#SYQW69#391)
This doc can help you regarding hosting the asset:
[https://doc.babylonjs.com/resources/external\_pg\_assets](https://doc.babylonjs.com/resources/external_pg_assets)
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### Author:  [@mrlooi](https://forum.babylonjs.com/u/mrlooi)
#### Post date: [August 28, 2020, 10:54am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/8 "2020-08-28T10:54:20Z")
There you go [https://playground.babylonjs.com/#SYQW69#397](https://playground.babylonjs.com/#SYQW69#397)
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### Author:  [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)
#### Post date: [August 28, 2020, 10:58am UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/9 "2020-08-28T10:58:19Z")
Thanks.
I think at this point I need to summon @Drigax 🙂
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### Author:  [@Drigax](https://forum.babylonjs.com/u/Drigax)
#### Post date: [August 28, 2020, 3:55pm UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/10 "2020-08-28T15:55:26Z")
Bizarre, the gizmo is broken after reimporting and even throws exceptions if you try to see whats up with the bone node positions…
[https://playground.babylonjs.com/#SYQW69#399](https://playground.babylonjs.com/#SYQW69#399)
I’ll try to take a look today
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### Author:  [@Drigax](https://forum.babylonjs.com/u/Drigax)
#### Post date: [August 31, 2020, 10:13pm UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/12 "2020-08-31T22:13:13Z")
I think I figured out what’s going on here, currently the vertices appear to be improperly skinned to joints in the skeleton:
[https://playground.babylonjs.com/#SYQW69#405](https://playground.babylonjs.com/#SYQW69#405)
Looking at the working source glb we can see that the joints array is in descending order:
Which breaks our output glb, since we didn’t modify the JOINTS\_0 attribute to match the new joints array:
I’ll look at how we can rewrite this attribute to match the actual scene, this probably should not be preserved from the source mesh data.
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### Author:  [@Drigax](https://forum.babylonjs.com/u/Drigax)
#### Post date: [September 1, 2020, 5:19pm UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/13 "2020-09-01T17:19:24Z")
Problem was definitely with how we were exporting our joint order:
Turns out we shouldn’t assume that order of elements in `Skeleton.bones` is equivalent to the actual Skeleton joint order, which is indicated by the individual joints via `Bone.getIndex()`.
>
Changing this logic so that we now properly export bones in increasing index value appears to address the issue properly.
>
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### Author:  [@Pryme8](https://forum.babylonjs.com/u/Pryme8)
#### Post date: [September 1, 2020, 5:45pm UTC](https://forum.babylonjs.com/t/gltf-export-bug-skinning-has-errors/13744/14 "2020-09-01T17:45:51Z")
YASSS!