Revit can make spiral objects though having a look at the fairly basic geometric shapes in Revit it might not seem obvious as to how this would be possible.
The trick is that you need to use an a swept blend and use some lateral thinking to get the spiral shape.
In this example we are looking at creating a sweep that runs as a spiral around the circumference of a wall.
First up, go to the Architecture Tab and then select the Component > Model in Place .
Select the Swept Blend tool . We will need to create the path that describes a semi circle running 180 degrees around the circumference of the building – we cannot use a full circle for this task and we’ll have to copy and mirror the semi-circles up to make the final spiral shape later on.
Now using the sketch path method or the pick the outside circumference of the wall.
The next step is to finish the path and then go to an elevation or section view where we can see the profile work-planes.
Start the first profile by clicking on the “select Profile 1” and then click no the edit button (you can also select a profile from the list of profiles loaded into the Project or load a new one here and use it).
If you are sketching a profile then select all of the sketch lines and then click Ctrl-C (for the next step). Once you’ve finished the profile then click on the green-tick.
Now click on the “Select Profile 2” button. If you are sketching the path then click Ctrl-V and mirror the profile and position it in the relevant place – note that as you want to give “height” to semi-circle (to make it a spiral) then you need to offset the 2nd profile up to a height that matches 1/2 of the 360 degree spiral height.
If you are using a project based profile then select the profile and using the options bar, mirror it and offset it in the “Z” plane to make the spiral.
Click the green-tick to create the swept blend.
Since we only have one part of the spiral then we need to select this part of the geometry and mirror copy it to the other side of the wall. In addition to this we need to then mirror the new part of the spiral from end to end (i.e swap the high part with the low part).
The next step simply involves copying the full spiral upwards as many times as needed to meet our needs.
In some cases we will need to truncate the spiral so that it doesn’t run a complete 180 degrees (perhaps at the top and base). In this case, select that part of the spiral and adjust the path to the required dimension.
You will note that the ends of the swept blend will always be vertical. If we need them to be shaped differently then we may need to use a void or another solid to make the end the correct shape. If you needed the end to be truncated horizontally then create a simple void extrusion and make sure it is in contact with the appropriate part of the spiral.
You can define a material for the sweep and add other parts of the geometry if required then click the finish button (green tick) to close off the in-place family.
Please note that this will work for positive geometry (such as the sweep above) but can also be used to create a negative spirals such as a thread in a screw.
And as always, have fun!