I receive drawings from other contractors and some of them always send me their drawings with the Z coordinate all messed up. When I open the drawings and I'm not in any command, and have my properties box open, under VIEW it tells me my Center Coordinates for X Y and Z. These drawings I get will say Center Z is at 1.03345E10 or something like that.
I used TREEDEPTH command to change that Z value to 0. When I entered the command it said my center Z was at 3020, so I entered 0, and now my properties box says my Center Z is at 0. This now allows me to dimension, and be able to grab my dimension grips in all locations. I haven't figured out how to fix the dimensions and text and leaders that were created at Center Z being 1.03345E10, I would assume those would need to be recreated at Center Z of 0. Then they will be grippable.
Also the trick of selecting all and then selecting which objects to modify in properties drop down bar at the top of the properties box, whether it's lines arcs, text, etc. That works only so well, somtimes blocks do not like to move to Z coordinate of 0 and usually dimensions will be messed up still. Z Centers of arcs and circles should be at 0, but you can't change splines and other objects as easily.
Thanks for the helpful command Modman_4