I have a 3D Architectural drawing that has been exported as a dxf file. I am using Blender 2.25 and importing works as I expected with the exception of fillets. I am interested in precise scaling of the imported object(s). I understand scaling itself can be done by selecting the object and either doing a mouse gesture, or pressing the SKEY or NKEY. What I would like to know is, is there anyway I can equate 1 blender unit(BU) to 1 real world Imperial or Metric unit such as meters, feet, inches or centimeters. I have a mixed preference in technical drawings; for architectural drawings I prefer using Imperial measurements, while in mechanical I prefer using Metric. This is why I would like to know a method for scaling both units. The only way I can think of at the moment to deal with this problem would be to make a key that represents 1 unit prior to import. After import I would scale the object until the key is equal to 1 BU. What I'm uncertain of in this process is, how would I know when the key is scaled to 1 BU. Would I have to rely on eye-balling the key against the grid or is there another, more precise method? Any help would be greatly appreciated. I hope I haven't left out anything important.