By Martin Phelps
A question often asked during a training course is “Can Dormers be created in Revit?” Although not new to Revit, this function is often overlooked. In this example the “Dormer” has supporting walls, a roof and cuts through into the main roof. The “Dormer” components can be either constructed away from the main building and moved to its correct location within the main “Roof”, as shown in Figure 1.
Or may be constructed at its correct location within the roof, as shown in Figure 2.
If the “Dormer” roof has been constructed using “Roof by Footprint”, by default the short lengths of the roof automatically have a “Roof Slope” applied to them. The end of the “Dormer” roof that interacts with the main roof must have the “Slope” removed, changing it from “Hipped” to “Gable” ended, this can be done by editing the “Roof Footprint”. To aid the visual charity of the model, it may an advantage to change the visual style from “Shaded” to “Wire Frame”, as shown in Figure 3.
First, join the “Dormer Roof” to the main “Roof” using “Join / Unjoin Roof”, select the edge of the “Dormer”, then select to interacting face of the main “Roof”, the result is shown in Figure 4.
The “Dormer” cut out in the main roof can now be made, select the “Dormer” command from the “Architectural” tab on the ribbon menu.
Select the main “Roof”, now select the components that make up the “Dormer”, I tend to select the roof first, followed by the inside edge, the three walls that make up the Dormer structure, this creates magenta lines that will be used to produce the “Dormer” cut on the “Roof”, as shown in Figure 5.
Using the “Trim / Extend to Corner” command to join the magenta lines and create a closed shape, confirm the edit by selecting the “Green Tick”, on the ribbon.
If the “Dormer” has been created with four walls, the back wall is no long needed, so it can be deleted, the three remaining walls can be trimmed to the main roof. Select one of the “Walls”, from ribbon select “Attach Top / Base”. In the “Options” bar select “Base” (“Top” is the default), and select the main “Roof”, repeat with the other two walls, the result is shown in Figure 6.
Finally change the “Visual Style” to “Shaded” or “Consistent Colours” as shown in Figure 7.
Once created, the “Dormer” and its components can be copied (this also includes the cut out in most cases), and positioned on the main roof, see Figure 8.