Roofs: Using Slope Arrows
The default method of creating a sloped roof within Revit Architecture is to make one or more of the roof boundary lines “Slope Defining”. This is fine if we know what angle we want the roof slope to be at. But what if we want to create a roof based on absolute heights? For example: We know the height at the eaves and we know the height that the ridge needs to be.
Yes, we could always use trigonometry to calculate the slope. But there’s no need for that. We just use Slope Arrows!
In the image below you will see that we have set a Level for the Eaves height and a level for the Ridge height.
We will now create a roof that has it’s geometry based on these Levels. First of all we’ll use the “Roof by Footprint” tool to set out our boundary sketch lines as normal…
You will see from the above image that I’ve set an overhang to the roof (300mm in this case). Now: Before we proceed, we need to switch the “Slope Defining” parameter to “Off” for each of the boundary lines….
I have turned these off because I am going to use a “Slope Arrow” to set my roof out. So let’s add the Slope Arrows now. You can find the “Slope Arrow” tool located on the “Create Roof Footprint” tab…..
One very important thing to note when using Slope Arrows is that the “Tail” of the arrow need to spring from a boundary line and the “Head” needs to correspond with the highest point of the roof- ie the ridge in this case. Here is the first Slope Arrow I have placed….
Before we set the parameters, let’s add the second Slope Arrow. Notice how I have simply used a Reference line to set out the centre line of the ridge.
Now let’s set the parameters. To speed things up I can select both Slope Arrows together, as the values I set are going to be the same. With both Arrows selected, I can now change the parameter values appropriately….
It is important that you leave “Specify” set to “Height at Tail”. We have changed the other parameters accordingly- “Level at Tail” is set to our “Eaves” Level. And “Level at head” is set to our “Ridge” Level. When we “Apply” these changes, our roof is created….
Obviously if we had just used one Slope Arrow and spanned it between two opposing boundary lines like so……..
…we would end up with a mono-pitch roof…..
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