Create More Furniture Designs With 3D Printing – Lithocubus

Today’s guest blog is from Wilson Peterson of Wedge Studio; Wilson is a practicing architect and teaches at the University of Arizona School of Architecture

Lithocubus is a seating device that was produced for the Acadia 2011design + fabrication competition, where it placed as a finalist in the furniture category. Lithocubus takes its inspiration and its name from the Radiolarians, a variety of plankton described by Ernst Haeckel, a zoologist from the University of Jena. In the 1860s and 70s Haeckel made scientific expeditions in the Mediterranean and to the Canary Islands during which he made precise drawings of the organisms he observed under his microscope.

Radiolarians are unicellular, but are divided into a membrane containing endoplasm and outer membranes containing ectoplasm. They have skeletons made of silica, that form by accretion between the bubble-like vesicles of ectoplasm surrounding the organism. In his book, On Growth and Form, D’Arcy Thompson described the minimal surface geometry apparent in the Radiolarians.

The structure of Lithocubus follows that of radiolarians. The aluminum frame of Lithocubus is defined by the interstices between adjacent bubbles. The resulting arched forms are rigid in compression. Affixed to this skeleton is an outer fabric membrane. The organization into a compressive frame and a tensile membrane follows the logic of large-scale tensile fabric structures. The membrane is a mesh fabric with an open weave, relatively transparent, to allow the internal frame to be seen.

As a seating device, Lithocubus can be placed on any of its six sides, affording three seating heights. The aluminum frame protrudes through the fabric to elevate it off the ground. The fabric supporting the body is held by tension rings at the corners and does not contact the frame. All faces of the aluminum frame are developable approximations of the synclastically curved forms derived from the minimal surface geometry of the bubbles. The fabric surface, a complexly-curved, tensile membrane, has a more fluid geometry.

Making a 3D print of the design presented a challenge: the design proposed a transparent fabric stretched over a rigid frame. If the fabric were printed as a surface, it would completely obscure the frame. I modeled the fabric as an open weave using Rhino Paneling tools. The model was printed on a ZPrinter 650 from Z Corporation. This allowed the frame and skin to be printed in contrasting colors all at once (no assembly), so the frame is visible through the skin. This was a much clearer expression of the design intent than would be possible with a monochrome print.

http://www.zcorp.com/en/Solutions/Architecture/spage.aspx