Interiors and Circulation

BIM for Architecture, Engineering, and Construction Curriculum


In this lesson, students explore techniques for creating several types of common circulation elements for multistory buildings, including stairs, elevators, and ramps. They will learn how to:

  • Create simple examples demonstrating circulation techniques.
  • Edit and customize elements as needed to model more complex conditions.
  • Add railings at floor edges and around floor openings.

Creating Simple Stairs and Ramps

As shown in Figure 1.4.1, stairs are typically composed of many elements, including:

  • Treads―the the horizontal surfaces that you step on.
  • Risers―the vertical surfaces between the treads.
  • Stringers―the supports for the treads and risers, which can be located at the sides of the stair or in the center (underneath the treads and risers).
  • Railings―on one or both sides of the stair.

Figure 1.4.1. Stair elements—treads, risers, stringers, and railings

Using Autodesk® Revit® software’s Stair tool, specify a few key characteristics, and Revit automatically creates a stair with all of these elements.

The simplest way to create a stair is to:

  • Specify the essential properties that set the height and length of the stair―the levels of the top and bottom of the stair.
  • Sketch the run line―an imaginary line that specifies the direction and length of each stair section.

Revit automatically calculates the number of risers required to connect the top and bottom levels and reports the number of risers created as you sketch the run line.

Ramps are created in a similar way using the Ramp tool, which also appears in the Circulation panel of the Home tab:

  • Specify the top and bottom levels.
  • Sketch the run line.

Revit automatically calculates the length of the ramp required using a slope of 1/12 for accessibility, but you can customize this slope as needed.

Modeling Custom Stair Shapes

You can change a stair in many ways to fit your requirements and the space available:

  • Use the Move or Rotate tool to reposition or reorient the stair.
  • Alter the stair properties (for example, the number of risers, tread length, or stair width) in the Properties palette.
  • Edit the sketch that defines the stair’s layout to change the boundary shape or the placement and shape of the risers.

You can also sketch curved run lines to create curved or spiral stairs. When creating spiral stairs, keep in mind that a curved stair run is limited to a rotation of 360°. If you need to model a stair with greater rotation, create several segments, then move and join them to create a continuous run.

Modeling Floor and Ceiling Openings and Adding Railings

While the Stairs tool automatically creates all of the stair elements needed to connect between two levels, it does not cut openings in the floors or ceilings that separate those levels. You can create these openings in two ways:

  • Use the Edit Boundary tool and adjust the floor or ceiling boundary sketch to include the layout of the opening.
  • Place a vertical opening or shaft opening element.

When creating stairs and ramps, Revit automatically adds railings to these circulation elements for safety. You can use the Railings tool to adjust these railings or add new ones in locations where they are needed:

  • Around floor openings
  • At exposed edges of floors and balconies

Modeling Elevators and Shafts

Modeling an elevator in the Revit software requires several steps:

  • Placing an elevator component
  • Creating a vertical shaft to cut openings in floors and ceilings
  • Adding walls around the elevator shaft
  • Cutting openings in the shaft walls for the doors on each floor

If an elevator component is not included into your model, you can load one from an external library.

The Shaft Opening tool is especially useful for modeling elevators because it can cut a vertical opening through many floors, ceilings, and roofs. When you move or modify the boundary of a shaft opening, the changes are automatically updated on every level.