Learn how to add a floor and then how to add openings in the floor.
Return to the plan view.
In the Menu Bar, click Geometry > (Floors) or in the Structural Design toolbar, click (Floors).
In the Floor dialog box, set the Thickness to TH12_CONCR and select Rectangle.
Select the points for the rectangle as shown below and close the dialog box.
Click the View tab to display the 3D view. The floor goes through the shafts.
Return to the Plan view.
In the Menu Bar, click Geometry > Objects… > (Rectangle) , or in the Structural Design toolbar click (Objects) and in the Objects toolbar, click (Rectangle).
Draw rectangles inside the walls as shown below for the shaft openings.