Arachne是一个通过三维打印技术完成的数字化外墙装置项目, 通过参数化设计手段实现了将一个建筑包裹得如同丝绸一般精致典雅的效果。丰富而又自然的表面肌理将建筑外墙的设计风格与建造手段带入了一个全新的境界。虽然这个建筑只有三层楼的高度, 但是强烈的外部特征和丰富的光影效果令其在一个偌大的商业综合体中显得格外夺目。同时三维打印这个先进的理念也因此项目而被植入到整个商业项目的运营之中。

　　 Arachne的空间造型既采用编程的设计手段生成, 也采用编程的手段输出加工数据, 并由ASW自主研发的三维打印机输出结构单元。所以说, 整个项目从设计到制作都遵循着一个严谨的数字化流程。Arachne采用干挂幕墙体系, 由近2 000块各不相同的三维打印构件组成。安装环节采用了特殊的节点设计, 将装饰件用螺栓固定于龙骨之上。虽然形态复杂, 但安装精度却达到了毫米级别。三维打印构件采用绿色环保的B1级工程塑料, 表面打磨抛光并用耐久的外墙涂料处理。另外, 采用三维打印技术还有利于进行后期维护, 如有破损的构件, 只需要调出该构件的数据重新打印替换即可。

　　 Arachne is a digital architectural endeavor to redefine an ordinary building with 3D printed components.To reflect its literal title, Arachne is designed and installed by the spatially intertwined lattices that hung on the building in the curtain wall mechanism.

　　 The mass gift-wrapped by Arachne is a three-floor building of 10 meters in height and 12 meters in width.This assignment was contracted to cover the main façades, which face an important public square, with a strong iconic articulation to collect attention.3D printing technology was selected to meet this requirement owning to its fabulous capacity of adopting the design concept.There are two major considerations:

　　 1.Give the building a standing-out interface by applying a special screen that presents a spatial and non-uniformed network.2.Pursue the subtle variations in detail during the form transformation via naturally following the internal forces.

　　 Geometrically, hexagon was chosen to develop the form from.Three groups of threads are braided for creating an interwoven network.This network is forced to deform in the location where have intersections with the building masses, such as the balcony and the rain roof.The density of the network is also carefully managed for an optimized appearance.Those threads are disappearing when turning around the building corner and ending up with a simpler formation.The whole network based on 3D printed components stays in an adaptive manner like a silky wrap.

　　 There are over 2000 components that could be categorized into two types:the hexagon joints and the connecting structures, which totally weight over 5 tons and took 50 large FDM printer over 4 months to fabricate.Each component is different from the others, and with specific tag system for inventory during the production and position mapping during the installation.The mullion grid is formatted by the surface’s hexagonal layout.Every part enrolls the system either by bolts or screws.The particle lights are located on the second layer for a backlit illustration.All information is outputted from a digital pipeline programmed in Grasshopper and C#, and visually investigated in Rhinoceros.

　　 To increase the durability of an outdoor installation in the material of PLA, a plastic 3D printing filament, there are mainly two important issues need to deal with:fire resistant and sun irradiance aging.Inflammable additive was mixed during the manufacture of the printable filament to satisfy the fire code.But the antiaging solution was more complicated.Unlike ABS, PLA is not friendly to most of paint.A kind of fluorocarbon gel was brushed before prime layer of the white paint, and coated with a glazing paint to finalize the cosmetics.This treatment process prevents the plastic from being oxidized and increase the durability.

　　 The installation was completed in three weeks.It is such a unique experience for the team that every single piece has a designated location, if there are any human errors, the contingent zone must be stopped to restore accuracy.There is an 8mm gap between every two pieces, and4mm silicon cushion pad is used to adjust the bias in case it’s deviation accumulates.

　　 It took one year to finish this 3D printed façade from the concept to installation.During this year, our design team had overcome many problems that had neither reference nor experience when taking 3D printing technology up to the building scale.After the last component was fixed in place, it was an expressive moment that the physical installation was situated in the way so identical to the digital model and renderings, it is only made possible by the new design and fabrication methodology.

　　 业主:越秀集团

　　 建设地点:中国佛山

　　 建筑师:于雷

　　 总面积:3 888平方英尺

　　 时间:2017