Model the base story

Model the main structural components that define the lowest level of the building: concrete walls and slabs.

Define the perimeter of the building after you set stories and planar thicknesses.

Use the selection window to apply supports to a drawing.

Add walls to the lower level of a structure.

Set a floor slab in a structure after you define the base level of the building.

Create an opening in a previously defined slab and use the Openings dialog to define its properties.