I want to create an opening or a hole to a lower floor, such as in a grand entry, loft, balcony, mezzanine or elevator shaft situation, but I don't know how to get rid of the floor in this area. How do I accomplish this task?
The Open Below room type is useful when you want to an area open to the floor below it, such as for a manually created stairwell.
To create an open below room
Define the area you wish to create an opening in by using any combination of the various wall tools, such as a Straight Railing .
If you don't want any walls or railings, use the Room Divider tool instead.
In Chief Architect X5 and prior, you can use the Invisible Wall tool if you don't want any walls or railings.
Using the Select Objects tool, select the room, then click on the Open Object edit button to display the Room Specification dialog.
On the General panel, select Open Below from the Room Type drop down menu.
Click on the OK button, and you should now be able to view an open area in a 3D view.