Now that the slab edge is complete, you can now add an interior opening:

• Select the 2nd level type.
• Select Layout > Slab > Slab Openings.
  
• Type 6 (150) for Slab Overhang.
• Click [Add].
• With the target cursor, click once at the end of the concrete wall enclosing the elevator shaft at grid intersection B.4-3. Move counter-clockwise to B.4-2, C-2, C-3, and close it at B.4-3. You should see the four edges of each opening drawn along the adjacent framing.
  Note: When "Left" is selected as shown above, always layout slab openings in a counter-clockwise direction. Moving in the opposite direction will result in errors.
• Repeat for the shaft on the other diaphragm.

Slab edge openings, like slab edge overhangs are always offset from the center line of the framing, but these edges are offset towards the center of the opening. Also, when a bay is enclosed on all four sides, the In Bay command can be used for a much easier opening addition.

• Repeat these steps on the 3_rd and Typical floor levels except use the In Bay command by clicking in the center of the bays.