Revit Architecture: Roof by Footprint

The “Roof by Footprint” tool is used for both flat and sloped Roofs. In this Revit Architecture tutorial I’ll show you how to use it to create both roof types (flat and sloped).

Tutorial Agenda

  1. Creating a flat roof
  2. Creating a sloped roof
  3. Creating gable ends
  4. Tidying up wall and roof junctions

In order to demonstrate the creation of both a flat and pitched (sloped) roof, I have created a simple building model…..



Let’s start off with a Flat Roof first. Select the “Architecture” menu and then “Roof”. make sure you have selected “Roof by Footprint” from the drop-down tools…..



You need to make sure you are in a Floor Plan View in order to use the “Roof by Footprint” tool. Normally when you are modelling a Roof in Revit, you will have a Level set up to control it’s height- this may by a Level that is also controlling the top of your external walls. Make sure the Floor Plan View you choose to work in is associated with the Level at which you want to create your Roof at. In other words. If you have set up a Level called “Top of External Walls”, switch to that Floor Plan View and THEN choose “Roof by Footprint”. For demonstration purposes, I have purposefully open the GROUND Floor Plan View and then activated the Roof Tool. Revit has worked out that I may not want to create a Roof down at the Ground Floor…..


Go ahead and change the drop-down Level selector to reflect the Level you want the Roof to be set at- you can always change this later, so don’t worry too much. Once the Roof tool is activated, the Ribbon changes to the “Sketch Mode” interface….



Make sure “Boundary Line” is selected and also the “Pick Walls” tool is active in the Draw Palette- see the image above. Also notice the Options Bar- see the image below. Please Uncheck the “Defines Slope” toggle on the Options Bar. This is because we want all the segments of our Boundary Line sketch to represent the edge of a FLAT roof. More on the “Defines Slope” parameter later on in the tutorial.



OK. So now we are ready to start sketching the boundary of our flat roof. Because we have the “Pick Walls” tool active, we can simply click on each segment of external wall and Revit will create a section of Boundary Line along each one. The Boundary Lines are the pink ones in the image below…..


Once you have gone around the complete perimeter of your building (clicking once on each wall segment in turn), you can then choose a Roof Type from the drop-down selector……



So we now have a sketch of where we want our roof to be and we have also chosen a roof type. We can now go ahead and click the “Green Tick” to instruct Revit to proceed and create the 3D geometry of our roof element…



Our roof is immediately created. If we switch to a 3D View we can clearly see our new Roof….



So that’s how to create a Flat Roof. What about pitched (or sloped) Roofs? Easy, we just use the same tool, in the same way- with one important difference. We ensure the “Defines Slope” toggle (on the Options Bar) is CHECKED. So I’ll go ahead and delete the Flat Roof we have just made, so that we can now create a Pitched Roof on top of the same building shell. I choose “Roof””, “Roof by Footprint” and ENSURE the “Defines Slope” box is checked (1). I also add a value of 500mm to the “Overhang” parameter on the Option Bar(2)- see below. This is because I want the edge of our pitched roof to overhang the external walls by 500mm…..



So again, we go around the external walls of our building, clicking on each wall element. Notice how Revit add the Boundary Lines with an Offset of 500mm away from the walls (2). Also notice that each segment of Boundary Line has a small triangular icon next to it (1). This tells us that these Boundary lines of part of a SLOPED Roof…..


In the Image below you can see that I’ve now again around the complete building and that my Roof sketch is complete….


If I go ahead and click on the “Green Tick” Revit once again creates the Roof geometry based on the information we have given it. You can see in the image below the completed Roof. Note the holes in the top of the Roof! This is simply the “Cut Plane” of this particular Floor Plan View cutting through (or truncating) the display of the Roof element.


If we switch to a 3D View we can better see the final geometry of our new pitched roof…..


Let’s go ahead and add a Gable End to our building. First of all select the Roof we have just created. Once selected, you’ll have the option to “Edit Footprint”…..


When you “Edit Footprint” you are taken by into the Sketch Mode you were just in. Consequently you now have access to the Boundary Lines. Go ahead and select one of the Boundary Lines segments that corresponds with where you would like to create your Gable End…..

With the Boundary Line segment selected, take a look at it’s properties in Properties Palette. UNCHECK the “Defines Roof Slope” toggle…..



Notice that when you do so, the triangular icon is removed from this particular Boundary Line…..


The means that Revit will NOT slope the roof up at this point- hence a Gable End will be formed. Go ahead and hit the “Green Tick” to remake the Roof. IN the image below you can see that the roof now has a Gable End. We can also see that there is triangular gap left in the gable wall…….



We can easily fill in this triangular gap by the use of the “Attach Top/Base” tool. Please refer to the image below when reading these instructions. (1) Select the gable wall. (2) Then activate the “Attach Top/Base” tool. (3) And finally click on the roof element…..



You can see in the image below that Revit has now extended the selected wall vertically so that it fills in the triangular void….



Next, let’s take a section through our building so that we can see how the external walls meet the underside of the roof. In the image below you can see I have created a Section Line through the building…..



If I switch to the Section View itself, we can see the junction between the top of the external wall and the underside of the roof…



Note how the top of the wall is horizontal and (consequently) do not meet properly. We can use the same “Attach Top/Base” tool to tidy up this junction. Once again select the Wall first (1). Then choose (Attach Top/Base” (2) and finally select the roof (3)…..



Revit then makes the wall meet the underside of the roof correctly….


Key Points

  • Roof by Footprint can be used for both flat and sloped (pitched) roofs
  • Sketch Mode is used to allow you to define the boundary of your roof
  • The “Defines Roof Slope” parameter allows you to toggle which parts of your roof are inclined.
This tutorial is taken from "The Complete Beginner's Guide to Revit Architecture" FREE online course.
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Posted in Autodesk Revit.