Amazon in the Regrade, Spheres

• Glazing tool built in 3 hours
• Steel curves rationalized to 3 radii
• Efficient dome manufacturing

NBBJ turned to Grasshopper because the Spheres combined several problems that were too interconnected to solve with conventional, linear design tools. The plant species inside the domes needed specific amounts of daylight that the mostly-glass structure could not always provide on its own, so the design team worked with horticultural experts and built a custom daylighting tool in Grasshopper to calculate usable light from the sun and from supplemental fixtures, and to test the effect of adding or removing lights in real time. That let the team quickly land on a lighting solution that gave each planting area the right amount of light with the fewest fixtures.

The same parametric approach carried through to the structure itself. Grasshopper's Galapagos evolutionary solver let the team iteratively divide the domes' sweeping, free-form steel curves into tangent arcs and measure their deviation from the original geometry until it found curves the steel fabricator could actually build, and a separate custom tool rationalized the glazing geometry into pieces sized for standard glass sheets. Building tools that could be adjusted and re-run, rather than redrawing geometry by hand for every option, was the only practical way to keep the architecture, structural fabrication, and glazing systems coordinated with each other.

The Spheres asked NBBJ to reconcile a striking architectural form with strict engineering and fabrication limits. The three domes needed a sweeping, free-form curved steel frame, but the structural engineer determined that the steel would lose too much strength if bent tighter than an 8-foot radius, so the design had to be rationalized into a limited set of buildable curves without losing its organic character.

The glazing carried a similar challenge: many of the glass panels did not fit standard sheet sizes, and the glazing subcontractor said costs could be reduced significantly if the piece geometry were standardized within specific size extents. On top of the structural and glazing constraints, the plant species selected for the interior needed daylight levels that an all-glass building in Seattle could not always supply on its own, requiring a supplemental lighting design that used the fewest fixtures necessary for each planting area.

Before building custom Grasshopper tools for the Spheres, a project like this would have relied on manual daylighting studies, hand-iterated structural drawings, and glazing dimensioned sheet by sheet, with architects, engineers, and the glazing subcontractor passing drawings back and forth any time one part of the design changed. Determining how much supplemental light each planting area needed would have meant separate manual calculations for every fixture layout under consideration, tested drawing by drawing rather than adjusted in real time.

Rationalizing the domes' compound-curved steel into buildable radii, and figuring out which glazing pieces would fit a standard sheet, would similarly have required engineers and fabricators to redraw and re-check geometry by hand for each iteration, a slow process poorly suited to a structure built from thousands of non-repeating, doubly curved panels.

Building custom Grasshopper tools let NBBJ solve the Spheres' interlocking structural, glazing, and daylighting challenges with far less time and rework than a manual, drawing-by-drawing process would have required. The custom daylighting tool let designers test different fixture layouts in real time and land on the arrangement that gave each planting area sufficient light with the fewest fixtures, rather than running a separate manual calculation for every option.

On the structural side, using Galapagos to iteratively rationalize the domes' free-form steel curves into a small number of buildable radii resulted in a highly efficient manufacturing and construction process for the fabricator, while still preserving the design's organic, vine-like appearance. A related custom tool let designers dimension glazing panels that did not fit standard sheets by pushing points in 2D and projecting the resulting shapes back into 3D, which made the modification process much faster.

The efficiency gain was dramatic: creating that glazing tool and using it to modify the glazing scheme took the team only about 3 hours, work that would otherwise have required far more time spent manually redrawing and re-checking each non-standard panel.