When you import or link a file to a 
  Revit project, you can control the graphic display of its layers in individual views. 
- Open a project view that shows the file. 
- Click View tab Graphics panel Graphics panel  (Visibility/Graphics). (Visibility/Graphics).
- Click the Imported Categories tab. 
- If you want the entire file to appear in halftone, select Halftone. 
- In the Visibility column, click to expand the DWG file name. 
  Revit lists the layers in the file. 
   
- To change the graphic display of a visible layer in the file: 
  - Click the Lines column for the layer, and click Override. 
	 
- In the Line Graphics dialog, specify the line weight, color, and pattern, and click OK. 
	 
 
- In the Visibility/Graphic Overrides dialog, click OK.