Jim Day
Ansys Employee

Instead of SPCing a node of the RB, use the SPC option in *CONSTRAINED_NODAL_RIGID_BODY.  Note that in this case SPCs will be with respect to the CG of the RB.   You can use the INERTIA option of *CONSTRAINED_NODAL_RIGID_BODY to re-locate the CG if necessary.

Then, to get the output you want in bndout, set SPC2BND=1 in *CONTROL_OUTPUT.