Будет норм открыть где то и пересохранить?
blender can't import ascii fbx files for reason here's the quick workaround for windows 10
-Right click the fbx file
-select 'Edit with paint 3D'
-in Paint 3D from the 'menu' choose 'save as' and save the file
-and that's it !..... import should work now on the new file..paint 3d saves the file in fbx format that blender can read ..