Can I dimension to a Centerline??  I select "Smart Dimension", and the mousie simply will not pick the centerline.  I've got a part that the client wants placed 54" from center of car, but I can't get SW to dimension it.  I tried putting a point on a visible line at the center of the car, and it won't let me mate the point to the midpoint of the geometry.  I tried sketching a little bitty short line and putting IT at the center, but SW won't let me mate the lise to either the midpoint of the geometry OR to my centerline.  Is this software TRYING to prevent me from doing this dimension????  SolidWorks R2010, SP0.  Thanx.