One problem when you use 3ds Max and Unity for your workflow is importing FBX assets. If you make your model and export it to Unity, chances are you are going to get rotations problems.
The Rotation Issue
If you import your FBX from Max to Unity the process seems to work alright. My teapot mesh seems to be alright and everything seems normal.
But if you look closely there is a weird rotation in the X axis with the value -89.981. If you see the preview window you will see your model rotated in a wrong direction.
How to Solve The Problem
This can be easily solved on 3ds Max. The problem relies on the pivot rotation of the mesh. Go to the Hierarchy Panel and on the Pivot section press Affect Pivot Only.
If we go into the pivot rotation mode we can see the Z axis is pointing up.
Rotate the X axis 90 degrees so the X axis is pointing up.
Now export again your FBX mesh with the Y up.
Import again your mesh into Unity and you will see now the rotation appears correctly at 0, 0, 0.
And that’s it! Now you can export and import FBX from 3dsMax into Unity without rotation issues.