Use the Structural Wall tool to sketch a structural wall in the building model.
 (Structural Wall).
 (Structural Wall). 
  Where is it?
 Structure panel
Structure panel Wall drop-down
Wall drop-down
 (Wall: Structural)
 (Wall: Structural) 
 Build panel
Build panel Wall drop-down
Wall drop-down
 (Wall: Structural)
 (Wall: Structural) 
Modify the Type Parameters of the wall to be placed by clicking the Edit Type button on the Properties palette.
If the walls do not display after you draw them, you may need to lower the view depth or create a foundation level to use as an underlay for the current level.