In ARES Commander you can choose between different unit systems for linear and angular units.
Command Access: UNITSYSTEM
or Options > Drawing Settings > Unit System

Select the unit system for linear and angular units here.
The precision can be set for both. This accuracy setting is set for the display that you see in the status line or at the cursor, for example, when measuring or drawing. It has no influence on accuracy during drafting. In this case, the program always calculates with the highest accuracy.
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This setting has no effect on dimensioning accuracy, since it is set in the Dimensioning Settings.
For angles, you can also set the position of the angle “0°” and the direction of the positive angle measurement.

The block unit format specifies how the drawing units of the current drawing are evaluated when it is inserted as a block into another drawing. It also determines the
conversion/scaling factor for external blocks when importing them into the current
drawing.