Hello, which rule/convention does Solidworks use for orienting the principal inertia axes(Ix Iy Iz axes of the pink frame shown with Mass Properties)? It seems Ix is along the direction of maximum moment Px, Iy along the direction of the minimum moment Py and Iz is along the direction of an "intermediate magnitude" Pz moment in between Px and Py.
The problem is I noticed the pink axes re-orient if I rotate the part in an assembly.
I chose the desired output coordinate system in the drop-down menu. I checked the "Moments of inertia taken at the center of mass and aligned with the output coordinate system" before and after the rotation. It seems the values Lxx, Lyy, Lzz are consistent before and after the rotation but the Ix, Iy and Iz change, for instance
Ix = ( 0.00, -1.00, 0.00) Iy = ( 0.00, 0.00, -1.00) Iz = ( 1.00, 0.00, 0.00)before and
Ix = ( 0.00, 1.00, 0.00) Iy = ( 0.00, 0.00, 1.00) Iz = ( 1.00, 0.00, 0.00)after.
The output coordinate system re-orient correctly with the assembly according to the rotation I impose.
I need these values for calculations in other program.
How do I get the correct values for Ix, Iy, Iz?
Thank you
