GLB mesh uploads have incorrect rotation on 26.4 version of viewer
tracked
AWalphaomega Resident
- Apply a rotation in Blender for a mesh, so that it is at zero rotation.
- Upload this mesh to SL using glb.
- Upload the SAME EXACT mesh using Collada.
- The Collada will be correct. The glb will have a 90 degree offset on the X-axis (rendering it useless if part of a scripted object)
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Dan Linden
updated the status to
tracked
Dan Linden
Thank you for the report, AWalphaomega, and for investigation, Gaia and Nyx!
Issue tracked at https://github.com/secondlife/viewer/issues/6618
Gaia Clary
So I became curious...
The SL viewer 26.1.0.22335142152, built on February 24, 2026, does not show the reported issue. I verified that the change for issue #5431 was merged after that build.
I also tested two local builds of the viewer develop commit (6909b2667a):
- With the change for #5431, the unrigged GLB has a 90° X rotation offset.
- Reverting only that change removes the offset.
BTW: Our recent skeleton fixes remain present in both test builds. Just saying :)
Nyx Onyx
The issue Gaia refers to relates to this Canny issue: https://secondlife.canny.io/bug-reports/p/corrupted-rotation-values-at-mesh-upload so the problem could have been present in SLV since 7.26.2 already, only reaching Firestorm in its version 7.2.5. Andrey Kleshchev might wanna have a look at this issue.
Gaia Clary
Meanwhile, i also compared the source codes of Firestorm 7.2.4 (which seems to not have the issue) and 7.2.5 (which apparently has the issue) and i could confirm that the change for #5431 was introduced between those releases. Nyx Onyx : This matches your reported behavior (FS 7.2.4 vs 7.2.5) and makes #5431 the likely cause.
Gaia Clary
I can reproduce this too. I created a 1 × 2 × 4 m box, exported from Blender as both DAE and GLB with unit scale and zero object rotation. the objects Rez similarly in world, but indeed the glb import contains a 90 degree rotation in its object data.
This behavior possibly predates the viewer version 26.4. I suspect the extra object rotation comes from this change:
That change moved the glTF-to-SL coordinate conversion from the mesh vertices into the object transform for static meshes. This appears consistent with the 90-degree rotation we are seeing.
BTW: Our recent fixes affect skeleton and skinning calculations. This test mesh has no rig or skinning data, so those code paths are not involved.
Nyx Onyx
I can confirm that there is a 90 degrees rotation on the X axis in the Edit window, even uploading a regular cube as GLB (I've only stretched it here)
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AWalphaomega Resident
no avastar
Nyx Onyx
Are you using the Avastar Exporter? If so, try untick this. I also include the section for GLB in the Avastar Exporter. I tend to stick to exporting static mesh with the built-in exporter.
Examine your exported DAE/GLB by reimporting them to Blender.
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