Working with Markups > Measurements > To Change the Unit of Measurement
  
To Change the Unit of Measurement
1. In the status bar, click the unit of measurement. The General-Units options open for the active view.
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To set the default unit of measurement, click File > Options, and then select Defaults. Select Units. The General-Units options open.
2. Select or clear Use same units as in the original file (when present).
3. Select or clear Show alert message when original units are not present.
4. Select a unit in the Default MCAD length unit box.
5. Click Apply to apply the settings and keep the Creo Illustrate Options dialog box open, or click OK to apply the settings and close the dialog box.