ByteBack

Fair point, Josh. I'm not 100% convinced but at the same time, this isn't a hill I want to die on The solution is just to apply the transforms to the mesh and armature in Blender, and then it will more or less import as expected. If there's a wiki or something somewhere about importing models, I think it would be worth adding that info there if it's not already been noted. I originally imported it from a FBX into blender to export as gltf into the engine. So if you're seeing similar issues, import into blender and apply rotations and scales to your mesh and skeleton. Either gltf doesn't have the scope to deal with certain transforms from FBX or many gltf implementations/loaders just don't deal with it accordingly. And given that mixamo is now owned by Autodesk, it probably uses whatever internal fbx handling they have to deal with manipulating the model in the app. @Josh Do you think it would be worth adding certain post-process tools into the model viewer such as "Scale meshes and animations" to deal with any hiccups when exporting from Blender? I get the feeling that a lot of users are going to be using assets that they bought from asset stores that have a variety of issues that are not easy to fix in the tools available to them such as Blender. For example, I tried to apply the scale to the transforms but it messed up my model really badly, and I couldn't work out why. So I just exported "as is" and figured I'd have to scale it some way in the engine. But because Blenders handling of units sucks, it exported at its normal size. It was a bit of a gamble though., and as I said; a lot of users are probably going to have similar issues.

As I mentioned in the original post, I did manage to get the model to look almost right by mucking around with the mesh rotation and root joint rotations in Blender and re-exporting. I figured that's going to be the way forward - don't have root joint rotations or mesh rotations. I will add though that the issue I'm seeing with the joints is pretty much the same if I were to export as an FBX and not take into account for the joint offset matrix in the skinning weights. This was an issue I had a while ago in my little toy-engine when I used this as a test asset. In the preview png in the editor, that looks to have had the model baked out as a static mesh without joint deformations; it's rotated exactly the way I would expect to be without taking into account for the joint offsets. Because this was how the mesh looked when I first tried it, and didn't bother with those matrices. I also think that the issue with Windows 3D viewer is that it's also not handling the joint offset matrices correctly. Because without the mesh scaling applied, the mesh IS huge.

Done. This is the version without having applied the rotations and messing around with the scale. barbarian.zip

I have an issue with importing skinned models. In the png preview, ythe model looks "sort of" ok. Except it's orientated so that the body is aligned with the x-axis (see barbarian_png_preview.png). When I open the model in the model viewer, I end up with the model looking extremely deformed as I play the animations (barbarian_preview_animated.png). It looks to me as if the importer isn't taking into account for the node offset matrix in the skin weights. Update If I fix the model & skeleton rotation in Blender (and mess with the mesh scale) and re-export; the model imports as expected. However, thanks to how the asset was made, if I scale the skeleton, it deforms into a twisted mess. But if I import with the skeleton scale set, the model is 182 units high in Blender, but somehow is only 1.82 units high in the previewer.