The 6’ tall 3D printed tower model

Posted by LGM | Wednesday, August 31st

The following is a piece we wrote for a September 2016 TCT Magazine article.  


DDG Partners, a real estate design, development, construction, and asset management firm, teamed up with LGM, the premier additive manufacturing firm specializing in 3D printing for architecture, to create a six foot tall, 3D printed architectural model with a fully customized digital lighting display.  The model was designed to assist the Corcoran Sunshine Marketing Group with apartment presales and is currently on display in Manhattan.  


LGM had developed a working relationship with DDG Partners over several years, building various models for projects in New York. While DDG had come to LGM initially for concept, structural, and basic massing models, they began pushing the boundaries to include more elegant and detailed models as their knowledge of 3D printing and its CAD requirements increased. Because DDG liked the look and feel of various preliminary tower studies and the workflow that had developed, DDG chose to contract with LGM for the production of a large showpiece model for the high-end sales center.   


The sales team was looking for a dramatic sculptural piece that would anchor the showroom. LGM selected a scale of 1”=8’ (1:96 scale) which translated to a 6 foot tall 3D print.  Early in the build process, LGM began making samples on plaster (CJP/”ZCorp”) printers and SLS parts in order to determine the best way to produce a 6 foot tall 3D print.  LGM primarily uses powder based processes because they allow complex overhanging geometry like decks, railings, and trusses to be built without requiring supports.  In addition, because the support materials are at least partially recyclable in powder processes, the material costs are lower for large hollow objects like building sections.  DDG liked the look of the plaster based models better than the SLS and the cost savings were substantial.  The weaker material, however, meant that certain details were “too thin to print”. Since LGM is a multidisciplinary shop with laser cutting, engraving, and CNC machining, the team crafted the primary structure and then inset laser cut acrylic windows with laser cut window frames and mullions to provide the higher resolution look traditionally associated with hand assembled architectural modeling.


The primary challenge for this six foot tall tower was not the overall timeline, but the fact that the design group and LGM were aware that changes were going to be occurring late into the model build cycle.  In particular, the penthouse, entrance, and some amenities in the middle of the structure were being designed much later than the residential floors.  To deliver the model by the date DDG requested, LGM needed to find a way to build a structure without starting at the bottom, top, or middle!  


In addition to a complex design release schedule, DDG wanted each apartment to light up either individually or in combination with other similar units and be controlled by a tablet computer. The model needed to answer buyer questions like “Where are all the 3 bedroom units located?” or “Show me where the meeting rooms are.” The lighting package required the interior of the model to be divided into discrete spaces designed to prevent light leaking from one space into another but still be simple to wire and assemble. To fulfill all the requirements, the model required room for a control computer, power supply, and wifi antenna.


The process of building an architectural model is unfamiliar to many service bureaus and additive fabrication teams. The designs are seldom printed as output directly from the architect’s native CAD.  Instead, there is considerable manipulation and “virtual modelmaking” where an experienced scale modelmaker abstracts and interprets the original design to create a product that looks appropriate at scale and works within the material and build properties of the additive fabrication process. For the DDG model, brick patterns, corner detail, and window trim all had to be modified. The digital interior was stripped out and replaced by light box walls, LED mounts, and 3D printable wiring chases for the LED controllers and power cables.  The roof mechanical enclosure was engineered to hold the electronics while the power supply was located inside a marble plinth that was built by the project masons in New York. Due to the relative weakness of the gypsum plaster prints, the model was constructed with a 2” aluminum pipe as a spine that also served as a conduit for power to the computer.   


This innovative design allowed each floor of the model to be produced as its own print. LGM’s high capacity enabled them to complete the actual printing on 7 gypsum printers in roughly a week of machine time. The team started with floors 7 through 15 and worked around missing data.  When a unit changed, it was reprinted independently, without disturbing the rest of the structure, dramatically minimizing cost and frustrations.  The digital control of the lighting meant that each LED could be daisy chained to the floor below rather than being home run to a switch panel. The final assembly should have been the simple stacking of the prints onto the aluminum spine and gluing them in place.  As nothing in prototyping goes perfectly, the aluminum arrived oversized and had to be hammered into place in a white knuckle operation. Fortunately nothing broke.   


While the choice of a 3D printed sales model over a traditional hand built display was initially surprising, the benefits in time savings, cost, and flexibility helped to justify the decision.  Commercial additive fabrication combined with traditional model-making craft yielded a product that was innovative, cost effective, and upheld the contemporary aesthetic of this unique real estate project.


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