The AddDimension(dim, opts) function adds a new dimension to or modifies options of an existing dimension in the Unit Converter.

You describe the options of the dimension by using the optional arguments. The opts argument can contain one or more of the following equations.

'display'=string

This option gives the text that appears in the drop-down box in the Unit Converter dialog box.  If this option is not given, the entry is dim.

'default'=truefalse

This option specifies whether the dimension appears as the default dimension in the Dimension: drop-down box in the Unit Converter dialog box. The default value is false.

'make'=truefalse

This option specifies whether the conversion tables are rebuilt after the dimension has been added to the Unit Converter.  By default, this option is set to true. If $10$ or more dimensions or units are added to or removed from the Unit Converter in one execution group, it is recommended that you execute the Units[Converter][MakeConverter]() calling sequence afterward.

$\mathrm{with}\left(\mathrm{Units}\left[\mathrm{Converter}\right]\right)\:$

$\mathrm{AddDimension}\left('\mathrm{action}'\,'\mathrm{display}'=''action''\right)$

$\mathrm{AddDimension}\left(\frac{'\mathrm{length}'}{'\mathrm{time}'}\,'\mathrm{display}'=''velocity''\right)$

$\mathrm{AddDimension}\left('\mathrm{energy}'\,'\mathrm{default}'\right)$