Earlier today, Santiago Calatrava‘s World Trade Center Transportation Hub opened to the public. While the architectural community has its set of criticisms on the topic (ranging from the Transit Hall’s poor spatial qualities to the project’s grossly exceeded budget), I’m hoping that the Dynamo community will appreciate it as an excellent case study in computational BIM!
As the case with any modeling software, there are plenty of different approaches to modeling something this complex. With Dynamo exposing a lot of experienced Revit users to computational design for the first time, I’m hoping to shed a little light on about how a form like this could be modeled algorithmically.
I focused on creating a parametric model of the soaring, cantilevered fins that characterize the building. The workflow I used goes something like this:
- Draw an arc where we’d like to locate the Oculus
- Choose how many cantilevered fins we’d like, and evenly generate that many points evenly along the arc
- Draw an ellipse at the ground plane, split it into two halves, and evenly generate points along each ellipse half. This will be the footprint of the Transit Hall.
- To give the Spine/Oculus some width, let’s offset our points away from the central axis of the Transit Hall
- Draw a line from each Base point to its matching Oculus point above
- Next, we’ll draw a Line object that represents each fin. We’ll produce those lines using the Oculus points as the start points, then a list of numbers for each fin’s length, and rotate it into place at the angle we’d like.
- Then we can join each of the Lines that represent fins and give it a Fillet to round its edge.
- Almost done – let’s finish up by hosting a series of Ellipses along each curve. The first width is set by us, and each subsequent Ellipse width diminishes as we approach the cantilevered point.
- Loft all of the Ellipses together into Solid fins.