The application uses SPxAPI for unit conversions. The unit type (Metric or Imperial) depends on the Work Place you select.
The SPxAPI FormatByType endpoint converts the dimensional values that display.
The SPxAPI ParseByType endpoint is used to check the values edited by the end user. The red square is shown around any text box in case of an error.
Value types (how values display or are formatted) are defined in the database. You can access the value types using dbEdit.