I’m on UE 5.7.2 and I’m running into a strange issue with Skeleton asset reverting to old bone positions whenever a Skeletal Mesh asset that modified its bones is not assigned in preview.
Here are the steps to how I got here:
1. I created a Static Mesh asset from an FBX import.
2. I created a Skeletal Mesh asset from the Static Mesh asset and chose to create a new Skeleton asset for it.
3. I then went through Skeleton → Edit Skeleton option in the Skeletal Mesh asset and created all of the bones for the skeleton.
4. I then went through the Skin → Edit Weights option in the Skeletal Mesh asset and added all the weights.
5. At some later point, I need to make a few changes to the underlying model, so I reimported the new version for the Static Mesh asset and given that I couldn’t find an option to to update it for the Skeletal Mesh asset, I just ended up creating a new one, using the existing Skeleton asset that I have.
6. Because the new model had a slightly different A-pose, I edited bone positions through Skeleton → Edit Skeleton option of the new Skeletal Mesh asset.
7. After switching over everything to use new the Skeletal Mesh asset, I deleted the old one.
8. I needed to make another minor tweak to the underlying model, so I imported it again and also created a new Skeletal Mesh asset for it, using the existing Skeleton asset.
9. This is when I noticed that the skeleton bones positioned themselves into old locations, from before I edited the skeleton in Step #6.
So, as seen in the above video, if I remove a Skeletal Mesh preview asset from the Skeleton asset, it reverts to the old pose. However, the more frustrating part is that whenever I add a new Skeletal Mesh asset using this Skeleton asset, it uses that old pose, causing obvious issues. The only way I could figure out around this issue was to open up a Skeletal Mesh asset where the bones are in the right position, go Skeleton → Edit Skeleton, copy all of the bones, go to Skeleton → Edit Skeleton of the new Skeletal Mesh asset with the wrong bone positions of the exact same skeleton (using the exact same Skeleton asset) and replace the bones there with the copied ones. This is copying bones of a skeleton to itself, but somehow with new positions.
That workaround is obviously not scalable and I’d like to use this skeleton for more assets, so is there a proper fix for this? Did I screw something up that’s obviously wrong? I assumed that editing the skeleton through the Skeletal Mesh asset would edit the actual Skeleton asset, but it seems that bone positions from such edits are stored with the Skeletal Mesh asset and not the Skeleton asset?