[Q2,Q3] = meshgrid(-pi:0.1:pi, -pi:0.1:pi);
for i=1:numcols(Q2),
    for j=1:numcols(Q3);
        M = p560.inertia([0 Q2(i,j) Q3(i,j) 0 0 0]);
        M11(i,j) = M(1,1);
        M12(i,j) = M(1,2);
    end
end
surfl(Q2, Q3, M11); surfl(Q2, Q3, M12);