Modeling Building Elements

Modeling Building Elements


In this lesson, you will explore basics techniques for using Autodesk Revit to create a building information model of a simple structure—a one-story residence.

You will learn how to:

  • Model exterior and interior walls.
  • Add doors and windows to the walls.
  • Create simple floor and roof elements.
  • View the completed building model.
Modeling Exterior and Interior Walls

Many designers begin the building modeling process by creating elements that represent the exterior and interior walls of the proposed building.

In Autodesk® Revit® software, you create walls by using the Wall tool to sketch lines that indicate where walls should be placed. As you sketch these lines, 3D wall elements are created in the model and appear in other model views.

The characteristics of the walls created are determined by the properties of the wall type that you have selected. You can specify the materials and structure of the walls being placed, as well as wall height and many other physical properties.

As you place or reposition walls in the building model, Revit software automatically joins the walls that intersect.

Adding Doors and Windows

After placing exterior and interior walls, a common next step for many designers is to add doors and windows to the model.

Doors are typically placed on the exterior walls to facilitate access and egress from the building as well as on the interior walls to enable circulation between the rooms. In Revit software, doors are hosted by wall elements. You create a door by using the Door tool to choose a door component and then place it in a wall that has already been modeled.

Windows are typically placed on exterior walls of a building to provide ventilation, daylighting, and emergency egress. In Revit software, windows are also hosted by wall elements. So the pattern for procedure for placing window components is similar to doors. You use the Window tool to choose a window component and then place it in a wall element.

The characteristics of the doors and windows placed are determined by the properties of the door and windows types that you have selected. You can specify the features, sizes, and materials by selecting different types as you place them. You can also easily change the properties of a door or window by selecting it and choosing a new type.

Creating Floors and Roofs

Most buildings also include a floor underfoot and a roof overhead. So to complete the complete the building model, designers will add these elements.

The shape of many roofs is determined by the location of the walls that support it. For these roofs, a simple strategy for designing the roof is to trace the boundary of the exterior walls (which is also called the footprint), and then specify which edges of the roof will be sloped. The shape of the roof is then determined by the intersections between the sloping roof planes.

In Revit software, the Roof by Footprint tool enables you to use that simple strategy, sketching lines or picking walls that indicate the boundaries of the roof and specifying which edges should create sloped roof planes. The characteristics of the roof created—including the materials and structure, as well as the slope—are determined by the properties of the roof type that you have selected.

The steps for creating floor elements in Revit is very similar to creating roofs. You open the Floor tool and then sketch lines or pick walls to indicate the boundaries of the floor. The primary difference is that most floors are not sloped (although they can be if that is appropriate for the model). The materials and structure of a floor are determined by choosing the floor type.

Learning Objectives

After completing this lesson, you will be able to:

  • Create a basic building model containing essential elements, such as walls, doors, windows, and roofs.
  • Understand how to place walls and choose wall types.
  • Place wall-hosted elements, such as doors and windows, and set their height and other properties.
  • Appreciate how to create floor and roof elements by sketching their boundaries and choosing their types.


Modeling Exterior and Interior Walls

In this exercise, students will learn how to:

  • Create walls by picking their location line and sketching them in a plan view.
  • Change the orientation of walls that have been placed.

Figure 1.1.1
Figure 1.1.1 - Placing Exterior Walls

Video Tutorial

Practice Exercise
  • Continue adding exterior and interior walls to the building model shown in the video tutorial, using the underlay drawing as a guide to determine their location.

  • Open the Ground Floor plan view.
  • Create new exterior walls using the Generic 8" wall type. Place the walls by setting the location line to Finish Face:Exterior and tracing the outer edge of the walls shown in the underlay drawing.
  • Add new interior walls using the Generic 3" wall type. Place the walls by setting the location line to either the Finish Face:Exterior or Finish Face:Interior and tracing the corresponding edge of the walls shown in the underlay drawing.
Figure 1.1.2
Figure 1.1.2 - Completed exterior walls of residence

Adding Doors and Windows

In this tutorial, you will learn how to:

  • Add doors and windows to a building model by choosing their type and placing components in host walls.
  • Change door and window placement.
  • Change door and window height properties.
Figure 1.1.3 -
Figure 1.1.3 - Adding window elements with proper height
Video Tutorial

Practice Exercise
  • Continue adding interior and exterior doors to the building model shown in the video tutorial at the locations indicated the underlay drawing. The door types and sizes needed are shown in the legend that appears in the plan view.
  • Add windows to the east exterior wall at the locations indicated in the underlay drawing. Use the window types and sizes shown in the window type legend that appears in the plan view.
  • Set the head height property for all windows to be 7 feet.
Figure 1.1.4 -
Figure 1.1.4 - Door and window elements placed in the project model

Creating Roofs and Floors

In this tutorial, you will learn how to:

  • Create roofs based on the building footprint.
  • Sketch a roof boundary and selecting the slope-defining edges.
  • Set the roof level and slope instance properties.
Figure 1.1.5 -
Figure 1.1.5 - Creating a basic roof and choosing slope-defining edges
Video Tutorial

Practice Exercise
  • Open the Living Area Roof Level plan view.
  • Create a new roof over the living areas of the project model by tracing the footprint indicated by the red model lines that appear in the view. These lines show the outer boundary of the roof, and all edges should be slope-defining with a slope of 3" / 12".
  • Open the Carport Roof Level plan view.
  • Place a flat roof over the carport area by tracing the outer boundary indicated by the blue model lines shown in the view.
Figure 1.1.6 -
Figure 1.1.6 - Finished sloping and flat roof over the project model


Modeling Exterior and Interior Walls
If a wall is connected to other walls, how will moving one affect the others?

Moving a wall will typically affect other walls to which it is joined. The other walls will stretch or shrink to try to maintain the connection.If two walls have been constrained using a locked dimension, then movements to one wall will be mirrored in the second wall to maintain the distance specified in the constraint.{slider What methods can you use to resize a wall?}

You can select a wall and then drag on the blue dots that appear at its ends to stretch or reduce the length a wall. You can also enter a new value into the temporary dimension that appears when a wall is selected. If you want to extend a wall to meet another wall, the trim tool offers an easy way to quickly and precisely join two walls.

Adding Doors and Windows
What do the temporary dimensions for a door or window element typically show?

By default, the temporary dimensions show the distance between the center of the door or window to the nearest adjacent wall or the nearest door or window. You can change the temporary dimension preferences for a project to show the distance to the edges of the door or window (rather than the center).{slider How can you indicate the hinge side and the flip of a door as you are placing it? After it has been placed?}

As you place new doors, you can indicate the direction that the door will swing into by hovering the cursor near the face of the wall on the interior side of the door. The hinge side of a door can be changed by pressing the space bar.After a door is placed, you can select a door and small blue arrows appear that enable you to quickly change the flip orientation and hinge side.

When you place doors or windows in 3D views, how is the level associated with them determined?

When you place doors or windows in 3D views, Revit tries to determine the appropriate level based on the closest level below the sill of the door or window. Often, this is a good assumption, but sometimes, it yields unexpected results.For this reason, it is typically better to place doors and windows precisely in plan views (which implicitly specifies the associated level), and then adjust their height settings in the properties palette.

Creating Floors and Roofs
When you create a roof by footprint, how is the shape of each of the roof surfaces determined?

The shape of footprint roofs is determined by the intersection of the sloping planes that are created for each of the slope-defining edges specified.The location and angle of the hip or valley intersections between the planes is determined by the relative angles of each plane. When two planes of equal slope intersect, the boundary between the planes typically creates a 45-degree angle with the roof edge. When planes of unequal slope intersect, the angle varies to resolve the difference.The location of the roof ridge lines are determined by the distance from the roof edges and the slope of each surface.{slider What determines the roof slope?}

The primary considerations for roof slopes are functional, such as drainage or snow removal. Once those requirements are met, adding slope is purely a matter of architectural style.Flat roofs are rarely completely flat, so will typically have a slope of 1"/12" to provide needed drainage. For example, ranch houses and prairie school houses typically feature very low slopes: 3" or 4" in 12". For taller roof styles, such as Tudor houses, roofs can be 6"–9" in 12". Finally, A-frames are even greater than 12" in 12".

Key Terms

Key Term
Type Properties
Properties are common to many elements in a family. A type property affects all instances (individual elements) of that family in the project and any future instances that you place in the project.
Instance Property
Properties that apply to individual instances (elements) of a family type in the project. Instance properties tend to vary with the location of an element in a building or project. An instance property affects only one selected element, or the element that you are about to place.
Project Views
Different views of the model, such as plan, elevation, section, and 3D views.
Boundary Lines
The outer limits or edges of many building elements, such as stairs, floors, or roofs.
Sill Height
The measurement from the floor up to the bottom of the rough opening or sill of a door or window.
Head Height
The measurement from the floor to the top of the rough opening or head of a door or window.