Mass/inertia properties of a full model

Question I have imported a model from NASTRAN or ANSYS, how to I compute the global mass properties ?

Answer The global mass properties are given by the projection of the mass matrix on the rigid body modes. Thus for inertia properties at the origin

 Up=upcom('load GartUp');
m=upcom(Up,'assemble m not');
rb=feutilb('geomrb',Up.Node,[0 0 0],Up.DOF);
IN=rb.def'*m*rb.def                   % inertia matrix at 0
CG=[IN(2,6) -IN(1,6) IN(1,5)]/IN(1)   % CG location
[u,s,v]=svd(IN(4:6,4:6));u            % principal axes of inertia
rb=feutilb('geomrb',Up.Node,CG,Up.DOF);
IN_CG=rb.def'*m*rb.def                % inertia matrix at CG