Out House

Actuated Active Bending Structure

MIT Spring 2021
Course: 4.154 / IN HOUSE
Instructors: Zain Karzan, Catie Newell and Virginia San Fratello
TA: Joel Austin Cunningham

Out House is at once habitat and inhabitant, space and object. It originated as a hack of a desktop CNC milling machine and can be understood as a cable-driven robot, however, whereas cable-driven robots are typically suspended from a frame or elevated structure, Out House relies on the restoring forces in three 3/8” GFRP rods to counter gravity. The cables are wound by three winch stepper motor actuator modules, which are controlled by a TinyG that receives G-code generated in grasshopper from CNCJS. When Out House is positioned on an impenetrable surface, the three nodes at its base are fixed to three steel strut channels. When outside on grass or soil, it can be staked to the ground.

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Encountering Out House.

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Out House in fully-compressed pose.

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Cable winding motor assembly.

Out House is an exercise in thinking about the expressive potential of a machine. When designing a CNC machine, typically a high degree of stiffness is desirable in order to accurately execute a set of instructions. In the absence of a need for accuracy, bending can be embraced as a material property. Here, bending is not the enemy of stiffness but rather the source of character for an emoting machine.

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Out House pose sequence.

Out House is situated in a lineage of machine-driven kinetic architecture that engages the human. The Robotic Building lab, led by Henriette Bier and Hyperbody, directed by Kas Oosterhius are two related research groups that have explored this area extensively (Bier 2011; Oosterhius 2012). A recent project that Out House bears particular affinity to is Axel Kilian’s The Flexing Room (Kilian 2018). Both Out House and Flexing Room can be described as actuated bending-active occupiable structures. Whereas the precedent research typically combines sensing with actuation in order to produce responsive, interactive or autonomous architecture in the case of Kilian’s work, Out House is an architectural character defined by the aesthetic qualities of its movements. Its attitude is not computed from within based on data from the environment, but is instead designed by a choreographer, who in their crafting of lines of G-code might also be called the digital fabricator. Digital fabrication here is defined as a process of translating a digital representation to a physical material reality. However, in the case of Out House, the digital fabrication does not involve the addition or removal of material at specified locations to produce a fixed object, as in 3D printing or CNC milling, but instead is a process of repositioning material to produce a performance. In other words, Out House reimagines digital fabrication as dance.

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Exploded axonimetric of overall assembly.

Suspended within the frame of the bending-active structure is a truncated square pyramid sewn from fluorescent orange ripstop nylon and open at top and bottom. As the structure dances between configurations, faces of the pyramid become more or less slack or taut, producing a reading of the pure geometric figure with varying degrees of clarity. In this way, the fabric serves as a register of the forces in the GFRP rods communicating the internal state of the structure as a kind of active ornament.

The fabric also serves as a shifting boundary between interior and exterior, producing a space that varies in its habitability based on the pose of the structure. As the machine bends between configurations, it produces a varying set of attitudes towards its occupants and onlookers. Over the course of a sequence of poses a person might encounter Out House from the outside as an object, enter as an occupant, be forced to sit as the structure compresses, and be expelled when the structure strikes an oblique pose.

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Exploded axonimetric of oculus.

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Exploded axonimetric of cable winding motor module.


Bier, Henriette. “Robotic Environments.” Essay. In 28th International Symposium on Automation and Robotics in Construction (ISARC 2011), edited by Soonwook Kwon, 863–68. Seol, Korea: International Association for Automation and Robotics in Construction (IAARC), 2011.

Kilian, Axel. 2018. “The Flexing Room Architectural Robot. An Actuated Bending-Active Structure Using Human Feedback.” In ACADIA 2018: Recalibration: On Imprecision and Infidelity. Proceedings of the 38th Annual Conference of the Association for Computer Aided Design in Architecture (ACADIA), ed. P. Anzalone, M. del Signore and A. J. Wit. 232-241. Mexico City: ACADIA.

Oosterhuis, Kas. HyperBody: First Decade of Interactive Architecture. Heijningen: JAP SAM Books, 2012.

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