Scaling Options
To open the Scaling Options, choose Options from the Utilities menu and click on the Scaling tab. The scaling options control how your document is scaled. See Setting a scale factor for more information.
Use Scale Factor
You can use a scaling factor in documents so all the measurements you see on the screen are scaled.
Drawing to Real World
These two fields are only available if the above option has been selected. Values should be entered here to set the scale factor of the document. For example 1cm to 1km.