From University of Science and Technology of China and collaborators, a cool hybrid method for fabricating 3D objects, called “CofiFab, a coarse-to-fine 3D fabrication”.
Using techniques familiar from large sculptures and architecture, they use 2D laser cutting to fabricate a snap tight space filling armature to support the object, and 3D printing to fabricate patches of the outer shell, rendering the fine surface detail. The algorithms do a lot of fussy work to come up with efficient sets of parts, and to work out the jigsaw puzzle construction.
This approach uses both techniques to their best advantage. The 2D parts are quick and cheap, and the snap tight structure is light and very strong. The 3D printing using models created from surface scans can render the detail beautifully, but is slow and expensive and fundamentally pointless for filling in large volumes (why lay down layer after layer after layer of unneeded plastic deep inside an object?).
By the way, the decomposition process is useful too, because it opens the way for parallel fabrication of the multiple pieces simultaneously on multiple machines. This allows a trade off of fabrication costs (i.e., number of machines, power consumption, material wastes, etc.) against time to delivery.
As I noted, this concept has been used for millennia to decorate buildings with carved panels over structural walls. It has also been used in large metal sculptures (e.g., the Statue of Liberty).
The algorithms are quite clever, working out the hidden snap tight structure, and then the visible 3D pieces to attach to it. I haven’t had time to really grok this work, but it is really, really neat.
The authors note that the current technique is mainly for “concave” objects, with quite a bit of space inside (to allow the snap tight structure). I’m sure this limitation can be overcome in several ways, including decomposition of objects into multiple “concave” pieces, and other combinations of 2D and 3D fabrication.
It is interesting to think about how this technique might combine with other advances in “origami”, foldable designs. I could certainly imagine fold-out-then-snap-tight structures. I’m not sure how to attach the shell, but let’s keep thinking about it.
In any case, the pieces produced by CofiFab are certainly amenable for “flat pack” shipping and assembly. So, this could be delivered a digital plans to be fabricated on site, or pre-made and shipped in a light, compact container.
- Peng Song, Bailin Deng, Ziqi Wang, Zhichao Dong, Wei Li, Chi-Wing Fu, and Ligang Liu, CofiFab: coarse-to-fine fabrication of large 3D objects. ACM Trans. Graph., 35 (4):1-11, 2016.