Detail panel
Subcategory panel, and select a boundary line style from the Detail Items drop-down. For more information on sketching, see Sketching.
For a sample detail family with a masking region applied, open the Nominal Cut Lumber-Section family, which resides in the following location:
%ALLUSERSPROFILE%\Autodesk\<product name and release>\Libraries\<language and locale>\Detail Items\Div 06 - Wood and Plastic\06110 - Wood Framing
After you add a masking region, you can sort the draw order. For more information, see Sorting the Draw Order of Detail Components.