defines the default prefix value for thickness dimensions.
default and available settings
- none* - defines no prefix value. the dimension value appears without any prefix string. you can specify a value in the prefix field, on the display tab of the dimension properties dialog box.
- t - defines character M-^Xt M-^Y as the prefix value. the dimension value appears with character M-^Xt M-^Y preceding it.
- user-defined - defines user specified prefix value.