How is your rotation expressed? Is it two angles t1 and t2 that are rotations in two planes (say xy plane and xz plane)? In that case use the rotz() and roty() functions. Alternatively use the rotation matrices:
Rxy = [cos(t1) -sin(t1), 0; sin(t1), cos(t1), 0; 0, 0, 1];
and
Rxz = [cos(t2) -sin(t2), 0; 0, 0, 1; sin(t2), cos(t2), 0];
newmin = Rxy*Rxz*([xmin; ymin; zmin]);
newmax = Rxy*Rxz*([xmax; ymax; zmax]);
