The attachments and Props exported from FBX and the custom normals have errors.
The attachments and Props, Custom Split Normals Data exported in FBX format are incorrect.
Take the Viking Axe in the default resources as an example 1)Import Blender using the automatic plugin 2)In the Mesh Edit Mode Overlays, turn on the "Display Split Normals" option.The incorrect normal line can be seen.
In the data properties of the axe, click on "Geometric Data" → "Clear Custom Split Normals Data",This will enable the correct normal vector to be displayed
Incorrect normal vectors can cause the lighting and shadow of Unity objects to appear as one side being black and the other side being white.
