I agree that this works. Move is still pretty easy though, just click anywhere in space and type "@-100,100" if the first massprop told you that the centroid was located at 100,-100. Basically, just use the @ prefix and opposite signs to move the object into position.
Thanks for the info, it's good to catalogue all the umpteenth different ways there are to accomplish the same result in Autocad.
Gerard Madden, P.E.
Middlebrook + Louie, Structural Engineers
71 Stevenson Street, Suite 2100
San Francisco, CA 94105