Advanced Unit Settings

Contains controls for setting the resolution of the design environment, which sets its size and accuracy. Opens when the Advanced button is selected, in the Working Units category of the DGN File Settings dialog box.

Unit Type

Determines if the units in this design file are units of measurement or some unitless representation.

• Distance
— Units are a unit of measurement.

• Unitless
— Units are something other than a unit of linear measurement. For example, Longitude or Latitude.

Resolution

Determines the accuracy of the design plane/cube. The Resolution setting defines the worst case accuracy for the design environment, which occurs at the very outer limits of the (very large) working area/volume. For example, working to a “worst case” accuracy of 0.0001 meters, the size of the design plane/cube is 900 million kilometers along each axis. Actual accuracy is many millions of times better when drawing near the origin of the design plane/cube, which is the usual situation. In almost all cases, therefore, there is no need to change the Resolution setting.

Changing the Resolution setting, changes the size of existing geometry in the model.

Working Areas (each axis)

Displays the length of each axis of the working environment (expressed in Miles or Kilometer when Unit Type is Distance) depending on the resolution. This area is recalculated, automatically, if the resolution is changed.

Working Areas (Solids)

Lets you reduce the working volume to a more manageable size when working with solids. This also increases the accuracy for solids. Maximum accuracy for solids can be achieved by setting the Resolution to 1,000,000 per Meter and setting Solids to 100 Kilometers.