How do I change the centroid orientation so my principle moments of inertia values are alligned to my normal force? Please see the attached diagram. The normal force is f1 which is parallel to plane 1. I would like the principle moments of inertia for components of a,b, c and d. The problem I have is that neither the x of y planes are normal to the F1 input load. You can see that they are oriented at some angle. I'm not sure if the principle moment of inertia is given in the section properties and is based on the output coordinate system.
Any help is appreciated.