Autodesk have recently launched a new roof timber framing extension for subscription customers following on from a similar tool for framing wall panels.
The tools, once installed, will appear on the extensions ribbon and have two modules, one for rafter framing and another for roof trusses. The extension will create the 3D timbers and trusses for a number of different roof configurations from simple dialog boxes with intelligent previews. Both of the tools require the creation of a Revit roof object and the framing and trusses are hosted on this object. If the original roof geometry changes then you select one of the timbers and select modify on the Extensions ribbon, this will force the roof to rebuild.
I will outline a brief workflow and then talk about some of the limitations and good things that I noted whilst testing the extensions.
As I previously stated, you will first need to model a roof using either the Roof by footprint or roof by extrusion. You then select the roof and choose the extension ribbon, in the modelling pull down you will see the two new modules, Rafter Framing and Roof Trusses.
In this example I am using the Rafter framing tool on a very simple gable end roof. Once the module starts up you will see that you can set the wall plates, each member can be configured and you may choose exactly which elements to generate. You can then move on to the trusses themselves.
Here you can choose the style of truss, number of required elements and each section size; again you can also choose to omit any sections that are not relevant. Click OK and your basic roof will now be complete!
This extension can handle most types of roof but the geometry must be planar, i.e. no curves. I did test it on a crazy and complex roof that I had modeled by picking mass faces. I was pleasantly surprised that this worked very well, seems to be very stable as long as all the faces on the roof are flat.
The module seems to be configured for timber roofs but I did edit a few of the framing families to light gauge steel sections to see if these would work. The tests that I did worked fine and when you update the roof the module uses the edit families rather than load the defaults back in.
Overall, a really useful tool and shows that Revit is moving in the right direction towards the world of fabrication and the associated details. I urge you to download from the subscription site and give this tool a go!