Standardizing bone names (e.g., Mixamo or Unreal naming conventions) is usually required after conversion. Conclusion
While online tools are fast, they often struggle with the specific nuances of XPS character models: Texture Loss
When to stop and use desktop software
Unlike simpler formats like OBJ, FBX supports complex data including skeletal animation, joints, and skinning information .
Online converters often focus on the geometry and bones. After converting, you may need to manually re-assign your texture maps (Diffuse, Normal, Specular) within your 3D software, as the file paths in the original XPS file often break during the conversion process.