Dynamo is an open-source Add-in for Autodesk Revit. Dynamo allows designers to design custom computational design and automation processes through a node-based Visual Programming interface.
The primary benefit of Dynamo over the other interoperability plug-ins such as Chameleon, Hummingbird, and Grevit, is its longevity. Since Dynamo was released several years ago, it has improved significantly, and my prediction is that it will continue to be developed until it becomes the industry standard. While its UI is still very clunky and a bit buggy, Dynamo is very quickly catching up to Grasshopper. Autodesk now has a dedicated team working on its development and will be releasing updates as they become available, which is an entirely different approach compared to Autodesk’s yearly updates.
So why use Dynamo over Grasshopper? The best answer I’ve found about this is from Zac Kron, who explains that:
Where Grasshopper works on top of CAD (Rhino), Dynamo is starting from BIM (Revit), and so the engagement with the building is different. While Dynamo does handle raw geometric stuff like CAD does, it really thrives on manipulating building components and systems. So, in a similar way that Revit can model walls and roofs by making a series of long skinny extrusions like CAD, it is more suited to manipulating sketch based objects like Walls that have a relationship to a larger building system.(Zach Kron, http://dynamobim.org/blog/page/3/)
While Dynamo starts from a particular workflow, namely BIM, its internal architecture is entirely independent of any single software platform and becoming more independent every day. Dynamo now has the same geometry engine that supports Inventor, Fusion, and other Autodesk products. No longer is Dynamo, and by extension, Revit, limited to the geometry available from Revit’s conceptual mass editor. In the words of Peter Boyer, Dynamo developer: “Revit, meet NURBS.”
Since Dynamo is still work-in-progress, some users may prefer to continue to use Grasshopper. What is important then is that whatever is made within Grasshopper is intelligently done so that it can be transferred later to Revit to be documented. We can think of this as DATA transfer, rather than GEOMETRY transfer by first extracting all the parameters from Grasshopper and then exported to Dynamo via Excel so that native Revit geometry can be created.