Without calling bpy.types.Mesh.calc_tangents() my models were being exported with tangent & bitangent fields all set to 0.0.
I'm not an expert at Blender scripting so if there's a more appropriate place to put this line let me know, but I found it needs to go before the attribute builders are constructed or UV coordinates get trashed.
Without calling
bpy.types.Mesh.calc_tangents()
my models were being exported with tangent & bitangent fields all set to 0.0.I'm not an expert at Blender scripting so if there's a more appropriate place to put this line let me know, but I found it needs to go before the attribute builders are constructed or UV coordinates get trashed.