To Change the Display of a Set of Levels Using Filters

In the Level Display dialog, click the List Filters icon.
All filters in the open DGN file are listed.
Select the filter to be applied.
Levels that meet the filter criteria display.
In the list box, click a level(s). You can click only those levels that contain elements, indicated with a dot in the level's Used column.
Note: Filters are useful for grouping associated levels for the purposes of viewing or not viewing as a group.