The Outer Skin. Constructing a complex building shape that had never before been conceived required the most innovative tools. Designed with 20,000 + curtain wall panels—including more than 7,000 unique shapes—the façade would have been challenging to envision using traditional computer-aided design tools. With parametric software, however, Gensler was able to create a system that balances performance, constructability, maintenance and design. Precise tolerances were achieved by placing lasers on the site to take measurements.