Use common sketch tools to sketch a path populated by a system of rebar.
 Reinforcement panel
Reinforcement panel
 (Path).
 (Path).  on the Options Bar and click the Flip Control
on the Options Bar and click the Flip Control  , so the rebar extends to the opposite side of the path.
, so the rebar extends to the opposite side of the path.  Mode panel
Mode panel
 (Finish Edit Mode).
 (Finish Edit Mode). 
 Graphics panel
Graphics panel 
  (Visibility/Graphics) and clearing the Boundary Visibility parameter under Structural Path Reinforcement.
 (Visibility/Graphics) and clearing the Boundary Visibility parameter under Structural Path Reinforcement. 
Revit places a Path Reinforcement symbol and a Path Reinforcement tag on the completed sketch at the center of the longest segment of the path.