Modeling & Meshing

Modeling & Meshing

How to interpret the “relative rotation” angles reported from a joint probe in Mechanical?

    • FAQFAQ
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      These are reported in X-Y-Z intrinsic order. instrinsic angles are angles where the orientation axis of the 2nd (RY) and 3rd rotation (RZ) must be recomputed based on the previous rotation (RX is done before RY, and RY is done before RZ). These axes are often labeled prime and double prime because of the new orientation. Order of rotation must be strictly adhered to with intrinsic angles. When going the reverse direction, trying to move from the final position to the initial position of the joint probe reported rotations, you will need to use the negative of each angle, and reverse the order: rotation about Z-Y-X. These angles are not to be confused with the definition of the LOCAL command in APDL, which uses Z-X-Y intrinsic order: Ansys documentation page: ANSYS Documentation > Mechanical Applications > Mechanical APDL > Command Reference > XIII. L Commands > LOCAL: LOCAL, KCN, KCS, XC, YC, ZC, THXY, THYZ, THZX, PAR1, PAR2 Defines a local coordinate system by a location and orientation. THXY First rotation about local Z (positive X toward Y). THYZ Second rotation about local X (positive Y toward Z). THZX Third rotation about local Y (positive Z toward X).