Revit can automatically apply a line style to silhouette edges. Silhouette edges are view-specific.
After you have applied silhouette edges to the model, there may be edges you do not want to display in silhouette. You can remove these lines as necessary.
To apply a line style to a silhouette edge:
Hidden Line, Shaded, or Realistic. Silhouette edges are not available for Wireframe or Shaded model graphic styles.
Graphic Display Options. To remove a line style from a silhouette edge:
View panel