Continuum Fashion
N12.bikini C7712DA Support Document
Design One of our main principles behind Continuum is pushing the possibilities of digital fabrication tools by creating designs that specifically reflect the technology behind the manufacturing process. Our dream technology would be something that could completely produce a garment, all in one piece, with the closures included, so no sewing is needed. It would be akin to knitwear, where the textile and the clothing pattern are designed in unity and made at the same time. Last year, we experimented with 3D printing to make the first completely 3D-printed, ready-towear, item of clothing.
The result is the N12 Bikini, named for the material it is printed in, Nylon 12. Nylon 12 is a solid plastic, but it’s strength allows it to be printed as thin as .7 mm, and it can be made into springs that bend and stretch. Thus our design is actually a 3D printed fabric, where thread-like connections form a material that also cohesively create the aesthetic design. It is flexible, and comfortably wearable. The nylon makes an ideal swimsuit material, being waterproof and chlorine safe. Designing the bikini was an endeavor of pushing the capabilities of the machine as well as working with constraints. A bikini was the natural choice to start with for 3D printed fashion, due to the low amount of material needed. The printer also has a set bounding box, and our original bikini design exactly fit within the print area in a single piece. Our first print models came out of the printer in one piece, with no additional assembly required. While conceptually exciting, this was really not efficient for production, due to the large amount of empty volume that the model took up. We felt it was important to design something that could be produced affordably enough for retail. Making this a ready-to-wear design was our main goal, as other 3D printed fashion experiments have remained experiments, or conceptual oneoffs. We wanted to prove that this design and production process can go beyond just a concept.
So, in our finished bikini design, the top is composed of 4 pieces that hook together. This is beautiful in its own way, as it packs flat, and provides a modular system for sizing. And, of course, it makes it easy to put on and take off. N12 is inclusive of more than just the bikini. The patterning we created in order to make wearable 3D printed fabric is visually appealing for a number of things. We also have a variety of 3D printed jewelry and accessories available. It is easy to see how the design method extends to a purse, or a necklace. 3D printing technology is really only in its infancy, and it is extraordinarily exciting to imagine what we can do as its capabilities improve. Right now, the challenges in the process also become points of inspiration. We have plans to do a dress, perhaps in modular pieces, and shoes… As we like to say, the future is an awesome place.
Technical With the N12 system, we are trying to reinterpret textile design through a computational lens. This is especially appropriate considering that textile design contributed greatly to the beginnings of computation.
General Motivation for the Pattern We knew we needed to subdivide our surface into small patches that could connect to each other by thin elements in order to achieve both the coverage and flexibility we were after. While we’d seen a somewhat similar system tried on a flat surface using triangles, we decided this was not going to work well in 3D, especially when trying to conform to the curves of a body. While triangles and other polygons are great for tiling flat surfaces, and even for approximating curved ones, they tend to result in a fairly wide range of aspect ratios, and thus the occasional very pointy piece. This problem is generally exacerbated if the pattern is trying to transition from one size range to another. Circles, however, don’t suffer from this issue. They are, of course, always perfectly round. 2D Pattern on Surface
Clem Rutter, Rochester, Kent
Jacquard looms were the first machines to use punch cards. They used these cards to create the complex woven patterns and texture of the final cloth. A Jacquard loom in motion is a very impressive, and computational, sight! Charles Babbage used the idea of punch cards as the input mechanism of the un-built analytical engine, and punch cards were, indeed, used as an input method for computers in the mid 20th century. Now, of course, modern computers are used to control many types of textile production, such as commercial knitting machines. However, these methods are still mostly used to create traditional fabrics with weaves that could be achieved by hand. With the N12 system we are attempting to use the variability, continuity and precision of complex 3D modeling in combination with 3D printing to produce a textile with new and unique properties.
Circle packing, at least on two dimensional flat areas, is pretty well understood. There are plenty of technical math papers on the subject, and implementations of various algorithms can be found for most programming languages and environments. Our requirements, however, were rather specific and complex. For one, the pattern is not flat, even though its initial calculation can be seen as “two dimensional” since each
individual circle is flat to its own plane. Instead it lies on an arbitrarily doubly curved surface. We also needed the size of the circles to respond to curvature and edge conditions of the surface in order to create smooth edges and a responsive pattern. Minimum tolerance values also needed to be maintained between circles. So, instead of a traditionally optimized algorithm that tries for maximum coverage, minimum size variation or similar metrics, we were looking for something quite different.
We found inspiration in the way a necklace of beads can coil against itself and form a fairly well packed but also well organized configuration.
The patterning starts with a curved surface, some geometry to indicate edges and value ranges for the circle sizes and tolerance parameters. The pattern begins placing circles at a point near the edge. Each subsequent circle tries to stay as near to the nearest edge geometry at possible. The circle’s size is determined using this nearness and the local curvature of the surface. Curvier
areas get small circles and flatter areas larger, both to help with accurately approximating the surface and to ensure flexibility where it is needed and efficiency of pattern where it is not.
Every time a bend or elbow is encountered in the surface edge a small gap will be left in the pattern. Gaps will also occur near the middle distances between edges where the placement of the next circle is less certain. After the first level of pattern has been created these open areas are infilled with smaller circles to ensure complete coverage, and to create a more interesting aesthetic pattern.
Now that we have all the circles, connecting them is relatively simple. Circles within a reasonable distance of a given circle are gathered and connection paths between them are determined. If a path passes within the radius of any other circle that connection is considered bad and discarded. This process leads to a connection diagram between all nearest neighbors. Connection intersections themselves are allowed. These occur more often in the small regular packing near the edges, leading to stronger and denser fabric there. 3D Geometry Of course, the placement, size and interconnectedness of the circle pattern does not actually create a fabric. To do that, volumetric 3D geometry needs to be created. There are two phases to this. The first is relatively simple. The circles are extruded at the minimum allowable thickness, copied and offset out. The two resulting plates are connected through their centers by a central cylindrical stalk.
Although the earlier patterning steps ensure a minimum tolerance between neighboring circles, due to the concavity or convexity of the surface some plates may intersect each other. These intersections are checked for and, if found, the radius of the offending plate is reduced.
Now we have good and non-intersection circle geometry. All that remains it to connect them together. Using the connections calculated in the patterning steps, 3D spiral curves and volumes are created which connect the circle assemblies from central stalk to central stalk.
The calculated connection curve is offset through the vertical center points of the starting and ending circle assemblies. A simple helix curve is draw around the result, leaving just enough space so that the piped volume will not touch the circular plates, and instead will only connect to the central stalks, giving the structure more flexibility.
Seams One of the goals of the circle patterning system is to be able to adapt it to any surface, at any size. While the code and concept work well enough at this we are, unfortunately, constrained by the physical limitations of the printer itself. Anything
that is to be printed must fit within the bed size of the printer. For a bikini for a rather small person, an entire model can just fit. However, to print efficiently, or to make a larger size, or to make garment larger than a swimsuit, the model will have to be bigger than the size of the printer’s bed. How can this be achieved without destroying the continuity and flexibility of our fabric system? As it turns out, the original pattern already holds the key. The circle pattern that you see on the outside can actually be thought of as three parts. The outer and inner surfaces (what you see) are thin circular disks. They are joined in the center by a stalk. The springs which connect these disks together all dead end into the stalk. So, to create a smooth seam in the fabric, I modified how these stalks are created.
Along each seam’s edge the disks are split from each other and alternately separated out to one side or the other. The stalks are divided in two, with one side receiving a hole and the other a pin. The springs for each piece are directed either only at the top half, or bottom half of these divided stalks as appropriate. The end result is a sort of alternating snap configuration that joins together nearly invisibly and keeps the integrity of the surface in tact. Our custom sized bikinis use seaming to create a form that exactly conforms to the wearer’s body, with minimal need for closures.