Building Envelope

BIM for Architecture, Engineering, and Construction Curriculum


In this lesson, students will explore how to use the Autodesk® Revit® Architecture software to place and work with the elements that compose a building envelope. They will learn how to:

  • Model wall types and design features.
  • Create new wall types and edit their structure.
  • Place and adjust the properties of doors, windows, and wall openings.
  • Create roofs with different shapes and slopes.

Modeling Walls Types, Structures, and Design Features

All walls placed in a building model have a wall type associated with them. The wall type includes a definition of the layers and materials that determine the thickness of the wall, so choosing the correct type for every wall is very important for creating accurate building models.

As you place new walls in your model, Autodesk® Revit® software automatically chooses the same type as the last wall created. You can accept this type or choose a different wall type using the Type Selector. You can also change the wall type after walls have been placed, but it is typically more efficient and better practice to choose the proper wall type as you place new walls.

You can create new wall types to model materials and wall assemblies that are needed for your design. And you can specify settings that determine the height of the top and bottom of the wall in the Properties palette.

Placing Doors, Windows, and Wall Openings

In Revit, doors, windows, and wall openings are modeled as components that are hosted by walls. You place these elements by opening the Door tool, Window tool, or Wall Opening tool, and then placing the component in a wall that has already been modeled.

While they are similar in many ways, the specific pieces contained in each type of component differ slightly because they include unique parts needed to perform their architectural functions:

  • Door components cut an opening in a wall, which is filled by a door frame and one or more swinging, sliding, or folding door panels. Many door types also include interior and exterior trim.
  • Window components cut an opening in a wall, which is filled by a window frame and one or more swinging or sliding sash panels. Many window types also include interior and exterior trim.
  • Wall openings cut an opening in a wall, but include no panels or other parts to fill the openings. Wall opening components are also available in the Revit Library to create nonrectangular shapes, and some components include trim.

You can change the sizes of doors and windows by choosing different types in the Type Selector or duplicating an existing type and changing its dimension properties to create a new size.

Doors and windows can be placed individually, or you can use arrays to quickly place many components using an even spacing. All of the elements in the array will be identical to the first and be spaced evenly along the length of the array.

After placing a door, window, or opening, you can adjust its:

  • Horizontal placement—by dragging the element along the wall or adjusting the temporary dimensions to precisely place it.
  • Vertical placement—by adjusting the Header or Sill height properties.
  • Orientation—by selecting the element and clicking its control arrows to flip the exterior and interior sides.
  • Hinge side (for doors only) and swing—by selecting the element and clicking its control arrows to change the location of the hinge and the direction that the panels swing.

Creating Roof with Different Shapes and Slopes

The Roof by Footprint tool in Revit enables you to create roofs with many different shapes and forms by sketching or picking the roof boundary and specifying which edges of the roof should create sloping roof planes. Using this tool, you can create model the common roof shapes typical of most architectural styles, for example:

  • Hip roofs—all roofs edges are slope-defining.
  • Gable roofs—some roof edges are not slope-defining, and gable end walls appear at these edges.
  • Shed roofs—one roof edge is slope-defining.
  • Flat roofs—no roof edges are slope-defining.

You can also build up more complex roof shapes by creating several independent roof elements to model gambrel roofs, mansard roofs, clerestory roofs, and dormer roofs. Where the edge of one roof intersects the face of another roof, you can join them to automatically determine the geometry of the intersection.

Revit also provides a Roof by Extrusion tool that enables you to create roof surfaces by extruding a surface from a sketched roof profile. This tool provides great flexibility for creating roofs that cannot be defined using simple sloped planes, for example a curving roof or barrel vault.