You can display alternate dimension units along with the primary units for all permanent and spot dimension types. For example, if you define alternate dimension units, you can place dimensions that automatically display Primary Units (for example, feet and fractional inches), and Alternate Units (for example, millimeters).
To use alternate dimension units for a specific dimension type, such as Aligned, modify the type properties for the Aligned dimension type. The alternate units will be displayed for all dimensions created with this type. In the following example, alternate units are specified for the Aligned dimension type. Type properties are set to display the alternate units below the primary units and to include a unit symbol (mm), and a prefix and suffix (the square brackets).
To define alternate dimension units
On the Dimension panel of the Annotate tab, click the type of dimension for which you wish to define alternate units.
On the Properties palette, click Edit Type.
In the Type Properties dialog, for Alternate Units, select one of the following options:
Right - alternate units display in-line to the right of the primary units.
Below - alternate units display below the primary units.
For Alternate Units Format, click the button to open the Format dialog, change the settings as desired, and click OK:
Clear Use project settings (if selected).
From the Units menu, select an appropriate unit.
From the Rounding menu, select a decimal place value. If you choose Custom from the menu, enter a value in the Rounding increment text box.
If applicable, select a Unit symbol from the menu.
Select Suppress 0 feet to hide leading zeros on dimensions, such as 0' 6". This options is available only for feet and fractional inches.
Optionally enter an Alternate Units Prefix and Alternate Units Suffix. For example, you could specify to have square brackets display around the alternate units: [1200 mm]
Notes
If Show Opening Height is selected (Aligned, Linear and Arc Length dimension types only), alternate units display for the vertical opening height as well as the horizontal opening, where applicable.
For Spot Coordinates, alternate units also display for the elevation if the Include Elevation type parameter is selected.
For Spot Elevations, alternate units display for both Top and Bottom elevations.
If Equality Text (EQ) or an Equality Formula is specified for a dimension, the alternate units do not display.