You haven't really explained why you are doing this. Is it something like you model an aircraft full size and then want to have a dimensioned 1/12 scale model? If so then do this... Make sure you are in the model entities context [i.e. not editing a group etc] Draw a line 12" long [assuming you are using inches]. Use the Tapemeasure tool and click the two ends of the line. The VCB should show 12". Immediately type 1" + <enter>. You are asked if you want to scale the model. Answer 'Yes'. The line and the rest of the model are now 1/12 the size they were... Erase the unneeded line. To make other scalings from a full sized version simply draw the line an appropriate length, so for 1/48 use a 48" line scaling down to 1"... A tool listing all the possible scales will take as long to use as this simple method and of course it's probably not have the scale you wanted in the list anyway! To reverse the scaling... let's assume 1/12... draw a line 1" long, Tapemeasure pick its end and type 12" etc, and everything is scaled back to full-size again...