Design & Fabrication

The bandshell design utilized one of the simplest and oldest parametric capabilities built into the Revit software, equation driven family parameters. This capability provides the user with a great deal of power and flexibility without resorting to the complexity API programing, or the visual programing found in dynamo or grasshopper. The technique is simple enough that a much wider segment of the architectural profession can participate in parametric design than is afforded be the other two methods, while somewhat constraining possibilities to the bounds of constructability.

The Frame

The form is derived from an array of slightly different 'triangular' frames. The location of each of the 3 points of each triangle is derived from a unique quadratic equation of the form y = a + b^2/c relative to a base line. As Revit parameters these equations are expressed as;

Offset_CL to D = Initial_CL to D + Increment Offset_CL to D x (Position Index^2)/20

where Position Index is the frames location in the array and c = 20.

The Connector

A characteristic of parametric forms is incremental change within a regular pattern. 52 frames were arrayed along a line to create the shell, each differing from the next as a function of the parabolic equations locating the end points of its members, resulting in 156 different connections.

To attain the benefits of economies of scale in manufacturing a single hinge like connector was developed that could be used in every joint condition.

The Form

The structural supports were developed by tracking with an offset, the center point of each joint. This resulted in two tilted planar parabolic arches for the rear supports.

The path of the more complex front supporting arch was generated by projecting the parabolic rear arch along the top chord of the frame and intersecting it with surface that was derived from the radial bottom chords.

The final forms were fabricated by a roller coaster manufacturer. Precise dimensional information was derived from the model and published via a Revit schedule of each frame.