The default working units for Facility Drafting are
|
|
Unit Name |
Label |
|
Master Unit |
Survey Feet |
' |
|
Sub Unit |
Survey Inch |
" |
|
Resolution |
96000 per |
Survey Foot |
The selection of working units is somewhat arbitrary. However, once standard units have been selected, it is very difficult to change to a new standard. These working units were selected for older versions of MicroStation, and were selected at that time because they provided an adequate size of working area without sacrificing drawing accuracy. The sub-units of 12" allow data input in both decimals of a foot and inches.
Working units control the size of an object in a design file. An object that measures 10'-0" in one working units, will not measure the same in different working units. By manipulating the working units, we are able to create design files with multiple drawing scales. See the section on Drawing Scales for more information.
All CAD files produced for the District shall use the standard working units provided in the seed file. Drawings that are created using non-standard working units will not be accepted.
Survey Feet vs International Feet
MicroStation V8 introduced the option of working in Survey Feet or International Feet. All files are actually stored in Meters, regardless of the working units settings. Each time a file is opened it is converted to the units specified in the RESOLUTION setting. All MicroStation drawings produced for the District shall be in Survey Feet. International Feet shall not be used.
In order to use Survey Feet, you must use the UNITS.DEF file that is provided in the Facility CAD Software. Without this unit definition file, Survey Feet will not be available.