Since this past June I have been collaborating on a sculpture for the new Museum of History & Industry (MOHAI) with the Seattle based artist John Grade. Due to the size, fabrication timeline, and necessary precision of connection points the project has deeply engaged digital design and fabrication while retaining the artists hand in the final meticulous crafting of its form.
The sculpture is comprised primarily of reclaimed timbers that were harvested from the Wawona, the historical three-masted schooner that was docked in Lake Union for many years, was towed to Sandpoint in 2009 for dismantling due to its failing condition.
Left: Wawona sailing at sea. Right: Wawona on its final voyage to be dismantled.
The wood sculpture will be supported by a steel skeleton that will transfer the weight of the sculpture up to a single 3-inch steel rod that is connected to the roof structure. This connection method will allow the sculpture to remain in a kinetic state while only being restrained at the base in a few locations. The final assembly will be 56-feet tall, weigh nearly 5-tons, and will reside in the main gallery of the Museum.
Left: Initial physical sculpture model. Right: Digital sculpture model
As with many reverse engineered digital design projects the initial concept was crafted by hand to convey the intention of the form. Geometry, from the artist’s initial scale model (above), was digitized and converted into a 3d model which allowed us to refine the form and to begin analyzing the overall shape for continuity and initial structural design. One of the many design considerations that needed to be evaluated was the overall sculpture curvature as it would directly impact the design of the connections. Rhinoceros allowed the curvature to be analyzed and refined (below) to produce a sculpture with smooth continuous curve transitions, which in turn created a fluid form. As the geometry was being revised it was also possible to continually evaluate the location of the sculptures center of gravity. This provided feedback on the angle at which the sculpture would hang when it was in a static condition and allowed for the adjustment of the sculptures mass and hang point to be accurately manipulated to achieve the proper hanging angle.
Left: Curvature analysis of sculpture form. Right: Center of gravity analysis.
Once the overall form was finalized the deconstruction of the monolithic geometry into manageable tiers took place. Once the section heights were defined it allowed the structural engineer, ARUP, to do a structural analysis which indicated how much steel would be needed to support each of the tiers when connected and hung in place.
Sculpture broken down into tiers.
At this point in time a Grasshopper definition was developed to locate all of the wood panels, steel collars, hanger rods, and every bolted connection. This definition allowed for structural decisions that were in flux to continue to change while allowing design of the individual wood panel members to update. Without this parametric approach to modeling the sculpture it would have been nearly impossible to continually update the several hundred components that make up the assembly.
A small portion of the grasshopper definition that defines the wood panels in the first tier.
Once the individual panels have all of their critical dimensions machined they are returned to John so that the extensive hand shaping can take place. The boards have both their external and internal faces shaped and fluted forms are added to the exterior. This combined effort between digital design and manual labor has afforded the unique opportunity to craft a truly unique work of art.
The sculpture is currently in production and is slated to be installed at the new MOHAI in Lake Union Park for the opening of the museum in November 2012.
Sketch of individual wood panel.
Drawing for wood panel layout and stock size selection.
Wawona boards being selected and marked based on color.
Some boards are laminated for overall material efficiency.
Wood panel being machined for steel connection.
Two exterior panels from the first tier once the flutes have been added and shaped.
Two interior panels from the first tier after being shaped.
Close-up detail of exterior flutes.
Cover Image: John Grade
Image 1: Right_Greg Gilbert / The Seattle Times
Image 2: Left_Alan Berner / The Seattle Times
Image 6: Clayton Binkley / ARUP
Image 8: John Grade
Image 11-13: John Grade