Revit Architecture: Forming a Roof Dormer using Slope Arrows

It is a relatively straightforward procedure to put a basic pitched roof onto your model, in Revit Architecture. The Roof by Footprint tool can be used to detect a chain of external walls and create a pitched roof based on their boundary. But what if we want to create a roof dormer in line with the roof boundary. In this tutorial, I will show you how to do that using Slope Arrows. (If you’d like to learn everything about Revit Roofs, you may be interested in my Revit Roofs Masterclass Course)

Let’s start with a basic pitched roof…..



So let’s create a dormer in this position…..



First of all we need to edit the roof boundary. Doing so will put Revit into Sketch Mode. It is best to be in a Floor Plan View when editing the roof boundary….



To form our Dormer, we need to first add a section of Roof Boundary with no “Defines Slope” parameter set, and then add Slope Arrows to this Boundary Line. So first of all I am going to use the Split tool to create a section of Boundary Line in the location where we want our dormer to be formed…..



In the image above it is important to note 2 things: 1) The section of boundary line that defines the extent of the dormer and 2) the “Defines Slope” toggle is initially on for this segment of Boundary Line. It is crucial that you turn this parameter OFF for this section of Boundary Line. Just highlight the Boundary Line and then you can toggle the parameter in the Properties Palette…



Now we just need to add 2 Slope Arrows to this length of Boundary Line. It is important that the Slope Arrows lie ON the line and that their “heads” meet where you want the apex of the Dormer to be. Just make sure you have Slope Arrow selected in the Draw Panel…



We can now go and add the 2 Slope Arrows to our Boundary Line…..



In the image above, I have outlined each of the Slope Arrows to make they easier to identify. If you select both of the Slope Arrows (once you have created them of course), you can set their parameters to control the slope of the dormer roof. Once you are happy with the Slope Arrow parameters, you can go ahead and re-create the overall roof form by clicking the “Green Tick“. This tells Revit that we have finished editing the Roof Boundary and forces it to form the new roof geometry. And here it is…….



All we need to do now is tidy up the wall beneath the dormer. We do this by selecting the wall and (with the wall selected) choose the “Attach Top/Base” tool and then select the roof.


This forces the wall profile to adapt to infill the triangular gap beneath the dormer….



And there is our completed roof dormer.


If you’re new to Revit Architecture, you may be interested in my freeComplete Beginner’s Guide to Revit Architecture84 part video tutorial course.

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