I've imported a coronary stent from CT imaging (on the right) and would like to place it into the tube on the left (a rough estimate of an artery) to ultimately run flow simulations.  Optimally, i'd like the centerline of the two objects to approximate each other so the stent is approximately in the middle of hte tube in terms of width and length.  I tried to do a width mate, but there's not face on the stent object, so it won't let me.  any ideas would be greatly appreciated. thanks!