I don’t believe that the rotations change when the length units change. In fact, the mass normalized mode shapes are always reported identically (for both displacements and rotations) regardless of what the units are.

The units for mass normalized modes are inches and radians. So if you need to get a maximum displacement of 219 mm, you would need to:

• Determine the maximum displacement in the mass normalized mode shape (I assume that this would be the maximum RESULTANT displacement at a node as opposed to in one particular DOF).
• Multiply all displacements in the mass normalized mode shape by the ratio of [219 / max displ].
• Multiply all rotations by [219 / (max displ * 25.4)] * 57.295 to adjust for the original inches and to further convert from radians to degrees. (Of course if you want to use meters instead of mm, than you would use 0.0254 instead of 25.4).