Unexpected rotation when exporting .fbx for Unity I have had no problems exporting .fbx files for Unity except recently some of my .fbx started to rotate the mesh. The asset is correctly oriented, but the mesh is rotated 90 degrees. Is there an explanation and fix for why this happens sometimes, and works properly otherwise?
That is because Blender uses +Z as a up direction whiles Unity uses +Y (most other 3D packages do so). So when exporting your file make sure you have pressed:
  

PS: I am not sure about the forward, you might have to try both -Z and +Z as I am not sure of Unity.