The outside of the New de Young Museum in San Francisco's Golden Gate Park is clad in over 162,000 square feet of copper panels covered with abstract pixelated patterns derived from over 650MB of images.
The concept of covering the largest copper-clad building in the United States with millions of bumps and holes came from the architects Herzog and de Meuron. The mechanical process and sheet-metal skills came from A. Zahner Co. The software which made it possible to accurately and efficiently manage the massive amounts of data, fabricate the panels correctly, and ship them halfway across the country while making it easy to install them in the correct order was up to me.
Image courtesy of A. Zahner Co.
Every Piece is Different
The abstract texture of a forest canopy was created from high-contrast digital images. These were then mapped onto the building surfaces and "pixelated" into a finite set of depths or diameters. This software allowed the architects to airbrush and smudge the texture with photoshop, then submit the images for automated processing.
This process allowed the architects to iterate the extraction process as many times as needed, giving them complete artistic freedom over what ultimately turned into "G" code for driving the numerically controlled hydraulic punch which produced each of over 8000 unique panels.
And while you're at it...
Hidden complexities and new feature requests appeared throughout the project. Some of these were internal; such as optimizations to the fabrication process or information requests from the installation team. Others were client-driven like "wouldn't it be cool if we could make the word 'deYoung' appear next to the entryway." These twists and turns in the requirements were easily handled. This was more complicated than clicking on the "thing I never thought I could do before" button, but many of the changes were handled within a few days with no disruptions to the ongoing production processes.
In addition to hundreds of other concerns, the bumps also had to be placed in an in-out checkerboard and the consistency of this alternation checked around the entire building and across image seams. To achieve the checkerboard with a uni-directional punch, two data files per panel were required to drive the fabrication. These had to be accurately registered to each other so that the 1/32" tolerances could be maintained when flipping a 39" wide copper sheet.
Image courtesy of A. Zahner Co.
While this was an absolutely one-of-a-kind project, the software was constructed in such a way that many of the components were able to be reused. One of these is my CAD::Drawing library, which continues to prove useful for quick geometric manipulations and has also served as the inspiration for the VectorSection graphics converter.
I also drew on the experiences from this project to develop a suite of programs which handles automated engineering of sheet-metal cladding and flat-pattern processing. These programs allow a project engineer to fully detail a complex cladding system in a few days – a process which used to involve weeks of error-prone manual drafting. To date, this system has been used on some of the final parts of de Young and at least three other completely different cladding systems.