Use the Lines tab of the Modify DGN Export Setup dialog to map Revit line patterns to MicroStation line styles.
In CAD applications, linetypes determine the particular dash-dot sequence, the relative lengths of dashes and blank spaces, and the characteristics of any included text or shapes in lines.
In Revit, these properties are defined as line patterns, which are specified in the object styles assigned to element categories. These patterns can be overridden for a selected element in a specific view.
By default, each Revit line pattern listed in the mapping table has a corresponding DGN line style generated automatically upon export. This line style matches the Revit line pattern.
To change the default setting for a Revit line pattern, click the corresponding value in the Line Styles in DGN column, and select the desired value from the drop-down list.
To change all the values in the table back to {Automatically generate line style}, click Reset All.