USDZ 3D models often have flipped normals during conversion due to conversion tools misinterpreting the original model’s normal direction data or using incompatible settings. Normals define how surfaces interact with light—if the converter misreads normals from software like Blender or Maya, or uses mismatched export settings, surfaces appear inside-out. To prevent this, recalculate normals in your 3D tool (e.g., Blender’s "Recalculate Normals" feature) before conversion to ensure consistency and reduce flipping issues.
