The control system of the MicroStation is very flexible. However, it depends on the knowledge of the actual size of the geometry. Many tools MicroStation depend on the file units to function correctly. This is the case for dimensioning tools, cell placement and SEO. Unfortunately, MicroStation cannot always deduce the file units in AutoCAD files. To precisely define the unit options MicroStation, you need to understand the content of the DWG file and the standards used to create it.

AutoCAD uses two types of linear units specified by the LUNITS variable. DWG files with engineering and architecture units (LUNITS = 3 and 4) are implicitly English units (feet and inches), so their units are known. The other types – Scientific, Decimal and Fractionnel (LUNITS = 1, 2 and 5, respectively) – do not involve a specific unit of measurement.

Starting from AutoCAD 2000, the INSUNITS system variable specifies the units of the Design Center blocks inserted into the existing drawings. The INSUNITS variable allows the type of automatic scaling that MicroStation perform when True Scaling is specified. Unfortunately, this variable does not exist in DWG files before AutoCAD 2000. In more recent version files, it may be defined inconsistently.

If the INSUNITS system variable is correctly set, when you open the DWG file in MicroStation, you can set Units options on Design Center Units. This is the best way to ensure consistency of units when you open a file in MicroStation.

To define Design Center units of a DWG file in MicroStation, use DWG UNITS keyboard input. This entry then displays the DWG/DXF Units dialog box. This dialog box allows you to control the Design Center Units (INSUNITS) parameter. Use the Save Settings command (File> Save Settings) to save the units settings in the active drawing file.

Use the keyboard input tool (accessible via F9) and enter the following command:

DWG UNITS

The next screen appears, then simply select the unit corresponding to the data of your file.