In COMOSYS, reinforcement placement operation for load carrying reinforced concrete units is performed staying within a very systematic structure. In this structure, surface subregion, stirrup and cross-tie reinforcement placement macros play an important role. Combining them together properly depending upon the type of load carrying reinforced concrete unit, it is possible to generate reinforcement layout for beams, columns, walls, slabs etc. automatically in a very fast and proper manner. It is also possible to place reinforcements into load carrying units with highly irregular geometry by using surface subregion, stirrup and cross-tie reinforcement placement macros easily. Surface subregion reinforcement placement macro is supported by operations. With the help of these operations it is possbile to make some small arrangements on the reinforcements after they have been automatically generated.