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First of all, I'm not sure this is an issue with UE4, but I'm not familiar with Blender to rule this out.
A user has reported an issue when importing a Rigged mesh from Blender it will add an additional bone. So with a single bone it will import 2. A mesh with 2 bones skinned will import 3 and so on. This poses a problem with assets that have a cloth asset (apx) file as the apx file only recognizes the original number of bones. So with that in mind, the single bone asset will work correctly, but when using two or more bones the apx file will see two bones while the skeleton has 3 bones.
As a simple test in 3Ds Max, when exporting a single plane that has 1, 2, or more bones skinned these come into UE4 with their correct number of bones. Not entirely sure if this is something that can be prevented on our end for Blender.
1. Open UE4
2. Import assets from attached .zip file
3. Open the individual skeletal meshes
4. Import and apply the corresponding .apx files to the material element
Results: The .apx files will not show the correct number of bones corresponding to the skeleton which will result in error message.
Expected: Cloth asset should apply to mesh that is imported.
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