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Digital Apparel Defined

The BodyHub avatar generator interface from Body Labs

The field of development known as “Wearable Technology” is suffering from a labeling issue. The technologies referred to are usually specific products that are not just wearable, but must be worn. They are designed to function in the context of the body. What constitutes “technology” is also fairly vague, since the phrase refers not just to electronic gadgets, but all sorts of innovations like specialized textiles, materials with engineered properties, prosthetic devices, or sensors and displays, in addition to “smart” products that have some level of computational ability and often communicate with other technology. I’ve broken down Wearable Tech into categories to provide an organizational framework for my work in custom-fit 3D printed products before, such as in my presentation at the 2013 Rapid convention (PDF transcript, video). Rather define these things for the audience every time we mention or discuss this family of technologies, it would be much easier to find relevant sub-sets that can be grouped under a single label. The phrase I use to describe my area of work is “Digital Apparel”. Of the many word choices available, “apparel” from the Old French “apareillier”, meaning “to make fit”, is an ideal choice to pair with the digital and technological processes that distinguishes the subject.

Digital Apparel includes a collection of information that defines a product worn on the body. The definition includes a three dimensional geometric definition that can be adjusted for different individuals. Customization can be defined through simple sizing variations or through parametric and generative components. In addition to geometry, an Item of Digital Apparel must be designed with specific processes and materials in mind, and specific intent in terms of function and aesthetics. It may also include transformational, iterative, or reactive geometries which are currently being covered by the oddly chosen phrase “4D [printing]“. The final criterion is that the product is made primarily through industrial processes.

The best way to address the many possible interpretations and misinterpretations is as question-and-answer. So here we go:

Is Digital Apparel clothing made on the computer?
It is the definition of the “clothing” while it is still on the computer. After production it is currently called either clothing (apparel), or wearable technology.

Is Digital Apparel referring to designs for 3D printed clothing and wearable technology?
It can, if the definition of those things is complete. Most advanced commercial wearable technology is produced along with PLM (Product Lifecycle Management) systems (Such as the ones from Siemens that work with their NX CAD software), and so contains the required information to meet the definition. 3D printed clothing is usually just a static 3D model, but if all the requirements are completed, such as a selection of sizes, and design for a specific material and 3D printing process, the design will meet the definition. As a simple example, a 3D design for something like shoes or a hat in a selection of sizes (while maintaining all key dimensions and features), designed with appropriate tolerances for FDM printing in PLA on a home printer, would meet the definition.

What about simple items like jewelry?
While they could be available in sizes and have material and process specified, the spirit of the definition is geared toward enabling discussion of pieces that distinguished by having larger size or complex shape that necessitates accurate size and shape, or specific functional requirements that require some knowledge by the designer about the context on the body. It also meant to refer to objects that are not purely decorative (have some technology component), so this usage would not be appropriate.

Smart watches and necklaces have tech, are they digital apparel?
Wearable technology, while an awkward phrase, is most pointedly referring to these gadgets, so that is the more appropriate phrase to use. If you wouldn’t call the resulting product “apparel”, you probably should not call the design an example of Digital Apparel. There is not a hard line between them however, particularly because the digital design and customization allows many more variations of form that don’t fall cleanly into categories like “Shirt” and “Pants”. I do think the Digital Apparel definition should be extended to forms that do not entirely envelope the torso, and so in some sense could be called “Accessories”, though that term is broad enough that it also refers to very small items. The phrases are not exclusive, but refer to different things. The core features of Digital Apparel are the customization and production information aspects that accompany the design intent.

Are there examples of of on the market already?
Yes. I offer 3D printed accessories and garments that are customized based on body scans and manufactured via 3D printing. There is software on the market such as Marvelous Designer that can be used to create a 3D dimensional design and output to 2D patterns for production. These patterns are cut through CNC, but are still assembled by hand, which falls short of being produced “by an industrial process”. However, there still can be no hard line, since even 3D printed designs are partially processed by hand. The important characteristics that helps distinguish Digital Apparel from traditional manufacture are the production specifications; which material, how they are cut and assembled- all of that information is needed for a complete Digital Apparel design. Doing something like downloading a 2D pattern, manually cutting the cloth and assembling it does not meet this definition. Aside from the fact the re-sizing would require experienced knowledge of the craft, there are numerous decisions made by the fabricator that would produce variability from one producer to the next. There is currently a fully automated robotic assembly project sponsored by DARPA for producing military uniforms that are custom fit for each individual. This would be an example of a Digital Apparel system. There are also several 3D weaving projects and 3D printing projects (such as the work I do with ThreeForm) that are carefully designed to be produced as repeatable, variable products. They are rare and expensive, not yet in mass produced form, but I would count them. One can also find examples of Mass-customization online, such as systems from Nike that create customized designs through a web interface. As final assembly of these products becomes more automated, the results become more pure examples of Digital Apparel.

If I extract an outfit from a video game for example, size it to myself, and 3D print it, is it Digital Apparel?
No. The model would have to be thickened and heavily modified in many ways to make it print and function. All of that input requires planning and design to match with particular materials, processes, and functionality of the result. It could be possible for a designer to formalize this information and creative a derivative work which is Digital Apparel, from just about any geometry they choose, as long as it meets all the criteria.

Is Digital Apparel a format?
No. There are a number of systems available for managing product information, and many of them pass on production information to the manufacturer. Again, this is not a black-and-white distinction, since for example a whole line of products might be designed to print in nylon12 using the common selective laser sintering 3D printing process. The actual process and material selection is inherent in the product and planned by the designer, but the producer may only offer that one choice, so there is no need to specify in any digital file. It should suffice that all the implications of the production process were planned by the designer to achieve a specific result, and as long as the design is “fit for the environment” that it is released into, it will successfully meets the definition.

How would anyone know what formats and software to use, and how to communicate the correct information?
Right now, all that is required is for the files to be compatible with the equipment, and all relevant information to be communicated along with the file, whether grouped into an archive and sent via FTP, transferred via a PLM system, or simply communicated along with an email attachment. Standards have not yet been created, and all of these things are adapted to the context, which is why this is not a consumer-level activity at this time.

What are the next steps? When do consumers get to buy Digital Apparel?
They can right now. In addition to hiring a specialist to create flexible digital designs, companies are creating software to simplify various parts of the process. The New York company Body Labs has a system that makes it simpler for companies to get input from customers to do customization in a less ‘couture’ arrangement. Ultimately we will all have digital profiles that are compatible with online shopping systems that will place orders and begin to manufacture customized garments – often with integrated technology components – with very little effort and relatively low cost.

The tension between the selective forces comes from the fact that those systems work best when many people wants the same thing, and customization works best when the customer wants a different thing from what is being commonly offered. I feel there will always be a spectrum of solutions, from the mass-produced simple functionality like a custom-fit piece of clothing with a simple sensor or indicator, to completely bespoke “wearable systems” that may enable complicated sets of interacting functionality, such as treatment for health issues or enhanced capabilities. At the extreme end of this development one might have most of their biological and functional needs covered, as in examples where a scientist might explore a remote area or even another planet.

All of these products that interact with the body must meet certain requirements to begin to evolve toward these final forms. Leaving out any specifications means work must be repeated for each iteration, and much of what was learned might be lost. It is by formalizing communication and design technique that standards will emerge to push forward development of both wearable technologies and Digital Apparel.


Fashion Presentation with Heidi Lee in Times Square

On September 8th, 2014, fashion-week once again rolled into new york. As part of a week-long series of art exhibitions in Times Square called “Art-a-porter”, Heidi Lee and I presented some new work in a very unique way.

Months earlier, after running through a few concepts and gathering a team, the project evolved into a unique hybrid presentation that was both runway show and video shoot. By that I don’t just mean recording the proceedings, but actually a full FX shoot with 3D tracking and green screen background. The idea was to capture the models performance and digitally re-create a new environment around them (in our concept, an other-worldly temple), then present the results as a commercial for the pieces. We had Andrew Strasser as our director of photography doing some nice steady-cam shots, and myself doing some auxiliary tripod shots, as well as two photographers documenting with still shots.

In addition to providing some 3D printed parts for the teams outfits, I also did the production management, making sure we had all our ducks in a row with logistics and other resources, since this was a very public show and we had specific requirements for the shots to be usable for 3D compositing later. We worked with body painter Dani Fonseca of The Body of Art to create “outfits” made of paint and 3D printed parts. These were all in line with a color scheme reflected in the hats. It took Dani and her team the entire day to paint the lovely models we had selected for the project, and so they made the trip in full paint across town from the studio. I was not able to get scans of the models beforehand. Relying on measurements and photographs, the parts were sculpted to fit and flatter. The parts were attached with adhesive and painted over to integrate them into the overall look.

Compositing test on stone background.

Lovely Nova gives us an anatomy lesson.

The footage looks great! The final production is set to release in February 2015, around the next fashion week, to promote Heidi’s new designs. Here is a little more from behind the scenes:

This project was definitely a stretch to pull off, but the results are worth the effort. When so many challenges are overcome in a project, it only makes it more satisfying in reflection. This was also one of the most fun, free-wheeling creative projects I’ve worked on in awhile. We were fortunate to have such an understanding and flexible host in Susanne Bartsch, the producer of Art-a-porter. The plan changed numerous times as the work progressed, and this one of those precious few spheres of life where the evolution of ideas is accepted as an inherent part of the process.

Purple Knights at 3D Print Show

For the opening of the 2014 New York 3DPrintShow Fashion Show, five gymnasts of the Purple Knights gymnastics team put on a choreographed dance performance to open the show. For this 3D printing fashion show, custom performance outfits were created for the Purple Knights based on their 3D scans.

Concept -
Backflips and Titanium.

After working with the gymnasts of the Lady Knights on an earlier promo video, we discussed making some customized accessories to bring a bit of theater and artistry to other shoots we had planned. The coach liked the sound of it. He asked about some other possibilities, and if they could perform wearing them! We had of course ruled out anything that could jeopardize a meet, but the challenge of designing for such exceptional requirements was an exciting prospect. Since I specialize in creating dynamic wearable 3D printed garments that allow the body to move freely, this was a perfect opportunity to tackle a really difficult goal. After floating the idea with the team at 3D Print Show, they were intrigued enough to consider devoting a segment of the show to a live performance.

The initial concept for the Purple Knights Armor was fairly simple- I wanted to show these graceful, powerful athletes doing their thing, and accent it with some armor-like designs that confer a mix of organic and mechanical references. There are also some more subtle components of my work in general that I’ll elaborate on in a minute. While custom armor is simple by itself, the original designs carried a lot of other ideas along and included far more exotic construction. I initially looked at DMLS (laser-sintered) titanium, but that process is actually very limited because it needs lots of support material. That material  is hard to remove from any shape but especially concave/hollow ones. While I might try that if I had access to one of those machines, the cost to outsource would be somewhere around $200,000 for each outfit, and that’s more than I was hoping to spend on this project. Considering other processes, I had the idea to first print the parts in acrylic resin using the SLA process. Those finely detailed parts were to be electroplated with a heavy coat of copper, then nickel. After removing the resin (and undergoing a few other processes), the metal shells were to be given a  structural coat of Titanium. Finally, a new process I heard about from Material Connexion involving a crystalline growth of sapphire over the surface, which makes it scratch resistant and naturally antimicrobial. The lining would have been Bamboo fleece. I was also looking into an additional external layer made of an aluminum-ceramic composite. One of the reasons the outfits look the way they do is that they are actually the middle layer between the lining and exterior plates.  Most of this did not make it into the final design, but as a concept, ultra light-and-strong Titanium Sapphire Armor is exactly what I was looking for. Combine that with the incredible athletic abilities of the Gymnasts, and you have a recipe for awesomeness. It would have been great to have more time to refine the designs, but I consider this a step in a long development process, so I’m happy to let people in on the early stages.

[Edit I'm adding the next section to offer an explicit description of what I was hoping would be a sufficient clear implicit message, but I find myself explaining this a lot, so to be perfectly clear, here is why I choose not to follow editorial standards of magazines like Vogue.]

One aspect of the show I’m most proud of does not even involve the designs, but rather how the performance relates to the context of a fashion show. The contrast between a gymnast and a runway model is pretty obvious. These girls are barely over five feet tall. They have about average body-fat percentage, but they are wrapped in a layer of muscle (30 hours a week in the gym will do that). Despite not fitting that imaginary “Ideal”, they are ideal by many other definitions, and that should be recognized.   As an aside, a very well known NYC designer launched his fall collection recently along with a video to try to capitalize on this envy some people feel toward athletes for their impressive physique and performance, but he did this by showing extremely thin models holding sports gear and standing next to equipment like weight lifting machines, when the person in the picture looks barely capable of holding their own weight. I think an exceptionally slim person can still be attractive, and the models are often beautiful, but associating that body type with athleticism is unrealistic. To associate it with health and fitness is downright irresponsible.  Body-types and other beauty standards have always been strictly enforced in fashion, and while some of it is practical (standard sizing), it is mostly a cultural echo chamber that has drifted far from the reality of what most people find attractive in today’s culture. I am proud to use diverse models in my work that reflect the reality of the world today.

When clothes – and many other products – are customized for each individual, the reviews and opinions of media suddenly lose purpose.  The old system of relying on magazines to give you your opinion is too slow to maintain an edge, and online versions of the same cannot differentiate themselves with better content than casual bloggers. You don’t need to know what’s “In” next season when what people want to wear was designed the night before. Further, the cultural innovations that inspire new designs are often produced by individuals that are not designers or celebrities, and are certainly not marketing people pushing viral content for brands. They may get clicks, but will have a hard time converting that into sales. Today’s audience is just too media savvy for old strategies.

Companies like Zara have already blown holes in the strict chronology and hierarchy in the season/branding structure and I have heard no strategy to address it but the same focus on brand exclusivity. The same tribalism and desire to imitate that served fashion during the last century may make it impossible to maintain brand value on style alone. Fashion was only “invented” in the 19th century when garments began to be mass produced. If we don’t need to worry about inventory, no bets need to be placed on upcoming styles. With the exception of a few brands that can rely on steady sales of their classic products, that leaves few options except to innovate, and to offer customization and a few other creative value-add mixes of product, service, and experience.

Ideation -
Documentation. Observation.

31 Lady Knights of the Purple Knights Gymnastics team.

I got to see the gymnasts in action during their practice in December, and later as the competitive season began in January. Documenting the season for the final video a few months later, I got to know a little bit more about the team, how they interact and work together, and more about the sport. Observation is an important part of the design process. When I speak of customization, I’m not just just referring to the shape of the body, but obviously I want the results to carry a bit of the wearer to the outside. I try to avoid doing this in a literal way with obvious references, but opt for subtle connection of form or symbolism, unless it serves an immediate goal in use or presentation of the design.

Injury. Flexibility.

One thing that stood out to me initially was the frequency and severity of injuries. Gymnastics is dangerous. The forces involved are great, and the routines can contain very complicated sequences. The smallest mistake is usually unrecoverable, and can not only harm the performance of the whole team, but cause serious injury. It is a lot of pressure to perform under and the team has been doing it consistently for years. The Purple Knights gymnastics team had won the USA Gymnastics National Championships and the East Coast Athletic Conference Championships for five consecutive years, and since that time have gone on to their sixth straight win of each. That consistency made me confident they could handle what we were planning to do, but I was also now keenly aware that there had to be a certainty that the design would not impede the motion of the performer. The design needs to be able distort easily, and even break or reconfigure if snags or extreme movements create pressure that could alter the path of the performer or her limbs. I also didn’t want the embarrassment of the design disintegrating in mid-performance in the case of a problem, so a further requirement was that if the design is distorted out of shape (reconfigured), that it automatically return to it’s original shape when possible.

Connections -

For every design I’ve made so far, I’ve designed or modified different types of fasteners. Eventually I may have a full library of whatever I need, but right now everything is very custom. With a parametric model, variations of new designs are easily produced, being sized, shaped, and angled for different parts of the design. After doing some rough math to analyze counts of connection points, fasteners, overall number of parts, volume, and time to print and finish, it was obvious that 6 weeks was simply not enough time to complete that many outfits. I really like the cross-stitch style I had used for some of my earlier designs because it is effective at resisting side-to-side motion while allowing stretching between panels. However, assembling the garment would be too time consuming and delicate for that many outfits under those conditions. Fortunately Manhattan’s fashion district is right nearby so I could get a hands-on look at other options. I also met with Becca at Chromat to discuss a project, and she gave me a review of some of the joining methods they use there. I switched to wide elastic straps instead of cord to join the sections, but used heavy cord for inter-layer connections that need to allow short-range out-of-plane movement. To actually join the straps, none of the stock detachable connection types appeared reliable enough for performance. The obvious solution was to sew the connections, but I would prefer the design was adjustable. The solution was found in an adhesive from 3M designed for assembling racing sails. It was very strong, but could be separated and re-attached by hand if needed.

Scanning -

Of the 31 gymnasts on the team, 9 signed on to be scanned.  Shortly before the first scheduled scanning date, the gymnast doing the choreography was injured at a meet. She stayed on to direct the team but obviously could not join the show. The remaining 8 were given full body scans using the fast, portable M3DI white-light scanner. This type of scanner is extremely accurate, and usually used for industrial part inspection. For comparison, this scanner is accurate to about 0.1mm, compared to ~1mm for a typical laser scan, ~1-10mm for photogrammetry, and ~10-20mm for PrimeSense (Kinect, Sense, Structure).

Each scan can create millions of data points, resulting in several gigabytes of data per person that must be processed through a pipeline of scripts, passing the scan sections through various stages of cleaning and reduction. They are all merged into individual bodies, and all the original color samples are projected back onto the skin.

Design -
Layers. Relative Motion.

To converge on a realistic solution, the final designs were restricted in size and complexity. I chose to focus most effort on what I found to be a tricky mechanical interaction between body sections. The focus areas were also chosen for suitability as a physical platform for functionality in future designs. Most of it derives from a concept of mine from 2007 that joins the chest and shoulders in a sort of utility vest, which was created for a mountaineering equipment design project. That expedition gear located a power source and wide-angle camera on the chest and multi-spectral stereo cameras on the shoulders. To generate aligned binocular vision (and extract 3D data) the relative position of the cameras must be exactly known, so the mechanical connection provides angular feedback in addition to stabilizing the platform. The motions of the clavicles and shoulder cuff are interesting, as it is one of the more visibly mechanical parts of the body. To transmit force around such a complicated joint would be an interesting challenge. Another plus with this configuration is that I find the area of the chest just below the clavicles to be an excellent site for a technology platform (electronics could be placed there without interference). This area is normally fairly flat, forward-facing and close to the bodies center of mass, so a complete understanding of any potential interference (contact with limbs, etc.) would be beneficial for future work.

Eventually the scope of the design was limited to meeting a set of requirements where each piece which must be firmly attached, yet also float gently over the body (distribute any pressure evenly) and adapt easily. It is a common assumption by people who have never worn a custom fit, printed garment that it would be uncomfortable, because we are familiar with form-fitting cloth garments that must use pressure to distort the fabric around curves. In the case of these garments, the pressure is so slight and evenly distributed, that it is actually often literally floating above the skin in many places. Perpendicular movement directions necessitated the use of multiply layers to achieve the needed articulation without passing off too much onto the elasticity of the joinery, which I believe would be a bit of a cheat. It would be easy to simply put on a body suit and glue/sew separate parts to it, but the point of the project here is to address the whole raft of issues that arises when having even a small number of rigid mechanical connections over the surface of the body.  With 3D printing one is tempted to rely on the “slop” (looseness) in the 3D printed hinges to give a fudge-factor, but in the end product illustrated by this concept, very fine tolerances would be needed to accurately locate the shoulder positions, and this information is needed to process the shoulder sensor data (to build a 3D image). We are familiar with science fiction, where powered mechanical suits are very thin and each piece seems to have unlimited relative motion (since it isn’t actually attached).  In this project emphasis was on directly addressing the issues of structure for functional reasons.

In early January, before the team was back on Campus for scanning, a complete prototype design was built over data from a non-gymnast performer with a similar body type. This gave a lot of information about part count, volume, and other things I need to know to break down the project into stages that could be analyzed. Multiplying that times the number of performers, the reduced complexity outfits were predicted to need about 300 hours of work, mostly in printing and finishing. The first week of January was already over, and the show was set for February 12th. I also had several pieces planned for the gallery at 3D Print Show, including two new mannequins, one featuring a new design that was only half done at that stage. Since that all worked out to another 150 hours, I was beginning to sweat a bit. By identifying the dependencies between critical elements, creating backups and alternative implementations, and prioritizing the many “nice-to-have” features, a robust plan was developed that could survive virtually any challenge.

Printing -

Because of the number of parts, total volume, and requirement for last minute changes, I went with extrusion printing for production. This also allowed me to use multiple suppliers for redundancy and faster execution. About half the parts were printed from ABS plastic on a Stratasys Uprint, and the rest on an Ultimaker-based system using PLA. All parts were to be given a metallic finish as a nod to the titanium of the original concept. Printing was going well until about ten days before, the Stratasys broke down [edit: actually this was previously scheduled repair/calibration I was not aware of, but the replacements for the worn parts were not on site, leading to a 3-day delay). This happened at the worst possible time, and Stratasys must be fixed by a licensed tech. Our guy in Massachusetts drove down and repaired it, but it wasn't looking good for scheduling all these parts with less than a week to go. Once we were back up and running, by some amazing coincidence a cooling fan burned out and printing again came to a halt. To his credit, the technician from Massachusetts drove down on a Saturday to come fix it again. Thank goodness, as the only other options would have added thousands of dollars to an already sprawling budget.

Finishing -

Sanding, priming, and painting 3D prints is a lot of work. Fortunately I had two assistants, both industrial design students, to help. Everything was scheduled so tightly that we had to drop one round of sanding and accelerate curing of the finish with heat (carefully, to avoiding melting the parts). The PLA parts also required a coating of epoxy, since they had a very sparse fill pattern and thin walls. After sanding they had many small holes and need some build-up for strength and finish. They were still not cured with mild heating, since normally they would sit for a week. I had to top coat less than 12 hours before assembly, leaving the finish very delicate during the assembly process.

Assembly -

The detachable ball-joint mechanism

For the final lineup we settled on a team of five, with one backup. There were about 60 parts in the final set, and while some were similar between outfits, they are all uniquely customized, so a lot of attention had to be paid to keeping them in order, not switching them or installing them backwards. I did a quick dress rehearsal with one completed outfit to get a feel for what kind of tolerances to use on the straps, and to test the joinery and motion of the garment. The length of each strap and cord was calculated from the model, and shortened by 20% to pre-tension the strap. The dress rehearsal gave approximate values, but each joint has different requirements, and I had no way of testing until I actually put them on the performers. I could have assembled and tested the outfits, disassembled them for finishing, then re-assembled them, but that test would have required many more hours and possibly prevented the parts from being finished. If a part could benefit from a change, there was no time to modify, re-print, and finish the replacement anyway.

In the days leading up to the show, I was struggling to catch up after all the lost printing time. Due to the timing of the completion of the builds, the only solution was to make sure the parts were immediately removed and sent to processing while the next parts were started, which meant being there at all kinds of odd hours and several all-nighters. In the model shop at the University of Bridgeport, six work areas were set up with each outfit and renderings of the final design. The paint room had one mannequin being refinished, one in final stages of Bondo work, and in the furniture lab one mannequin was still a stack of raw cardboard slices needing to be laminated together. The outfits for those mannequins were also being refinished and having their elastic components replaced. In addition to all that activity, I had another designer with me who I was helping with the finishing of another elaborate 3D printed design, also for the 3D Print Show.

Performance -

On the morning of the show I took the train to NY with the team. The backstage area of the fashion show was the most beautiful sort of chaos, and exactly why I love doing this sort of thing. All these models, bless them, were tasked with displaying items that were more often wearable sculptures rather than any sort of clothing, and most designs were not ergonomic to say the least. I got the feeling many of the pieces had never been worn before. Some designers were present to see through the presentation of their work, but in some cases the pieces never made it into the show, or were not shown as intended. Some designers though, went the extra mile to ensure the show went off without a hitch, helpfully applying their experience to sort out last minute issues. Julian Hakes in particular took extra effort to repair some broken pieces. I lent him some adhesive to fix the heel of a serpentine shoe, and it was only later I learned it was not his design, but he diligently asked around the whole place trying to find a solution. My hands were very full, since the final assembly of the outfits was done on-body. I was fairly calm and focused by that time though, since there wasn’t any mental bandwidth left for anything else.

The first run of the performance was for the press. The knights did a great job, sailing through the air with ease, inches from the spectators on either side. There was mention of a dance performance on the website in the lead-up to the show, but it would have been nice to have someone MC the event and explain who we were and what we were doing, since the crowd was mostly fashion editors, and they have very narrow views of what constitutes a fashion show. These viewers of fashion shows are normally there to analyze styles that will influence buyers for the next season. As opposed to illustrating a trend, this show, and especially the Knights performance, would be better described as performance art with “fashion in the future” as a theme. The second performance also went off without a hitch. The girls hit all their choreographic cues, and every connection on every outfit held together for the duration.

This whole project went exactly as planned, and I’m grateful to the organizers of 3D Print Show for giving us opportunity to present. Thanks also go to Kim, Cailyn, Chisaki, Zhara and Lissette who performed in the show, and Erin Turner who put together the choreography. Below is an edit combining the two runs:

Extrusion Printing – A Quick Review of Strengths and Weaknesses

A stacked build with 47 parts for a 3D printed outfit.

When someone says 3D printing nowadays, they’re almost certainly referring to desktop extrusion printing of a single material, usually PLA or ABS. I recently did some technical edits for a book on 3D printing, and was surprised to see that this idea is so deeply ingrained in media and culture.  One of the points I emphasize in my 3D printing classes is that most of the weight put into this perspective is due to the marketing from companies trying to push printers or filament. As a consultant that puts me in an odd position when dealing with the consequences. Additive manufacturing has great potential, but it is important not to make statements that lead to false conclusions. Media and marketing often strive to present things with just the right level of evasion that will allow them to avoid taking responsibility for the confusion they create. The purpose of this post is to put, in a nutshell, the most important information that printer companies are not excited to tell you, but are essential to make a proper decision.

1.) Books about printing already assume you have decided to buy a printer, so look at other options first.  In reality you need to look at the size, material, and number of things you’d like to print. Home printing can be fair quality, but if you value your time your are probably not going to see a return on your investment unless you print several object per week for a year or so.

2.) Home printers are great for education, but not mission-critical business applications. DIY printers are designed to be inexpensive and repairable at home. Every business I know using a home model for continuous production has at least two, and a technician to operate and repair. If the printer is in regular operation, this is a busy job, since each printer has an “up-time” of about 60-90%. They are great in a support role for larger machines. When the industrial systems are occupied, inexpensive satellite machines are great for test prints and radically increase efficiency. Most small businesses I see using a single small machine have it sitting cold, for whatever reason, about 90% of the time.

3.) Single extrusion is limited. You can print anything…that doesn’t have an overhang more than about 45 degrees from vertical. Extrusion printers must always print on something, either a base plate or plastic on a previous layer. Many times it just isn’t possible to orient a design to print well. An unsupported section can lead to distortion, bad surface finish, or even a crashed build where your output looks like a pile of plastic spaghetti. Using auto-generated support mars the finish is labor intensive. Sharp tools are often used to remove support, making this method unsuitable for children.  Dual extruder machines often use a soluble support material that eliminates these problems. In fact, while it can waste some material, I have had great luck with stacked builds using these machines. One single build can output dozens of parts, saving tons of labor and set-up time. The 6″x8″x6″ build shown at the start of the article contains all the parts for an entire 3D printed outfit (she’s a petite 4’10, 93lbs).

To lay out and print the parts individually would have taken at least five overnight builds. The above stack was printed in about 40 hours. The pieces were roughly separated afterward to accelerate the chemical support removal process, so the whole job was done in 48 hours. Laser sintering works this way as well, with stacked builds being the norm, but easier cleaning (support is powder, removed with compressed air instead of chemicals).

4.) Outsourcing is usually easier. How many parts are you printing, how large are they? If your answers are “many”, and “small to medium”, do it with extrusion. If it’s a one-off project or cannot fit on a printer you might consider a composite of many prints, but accuracy will be low and labor high, so this is really only a solution if it must be done on a very limited budget. Desktop extrusion can be outsourced, too. Printer networks like 3D hubs enable you to connect with anyone in your neighborhood with a printer, and at $0.25 per cc, they make the creation of small but bulky parts very affordable. Note that by “bulk” I am speaking of overall density and the proportion of volume to surface area. Extrusion has a sweet spot in the middle. Beyond a certain size, outsourcing can overcharge for thick parts because they charge for the space inside, which is often sparsely filled. If you have deal with an individual, try to negotiate pricing based on material and print time.

I use extrusion printing all the time, and it is convenient to have a machine at home if you have the time and space to deal with it. Its great to wake up in the morning and having the part you modeled last night ready to go without missing a beat. If you want that feeling several times a week, or if you just want to tinker with the machine itself, DIY is the way to go. If you don’t have a clear idea of what you would make, and especially if you have not yet developed your modeling skills to make whatever you think of, I’d strongly suggest looking at other options – even other manufacturing methods – that might be better suited to your use and lifestyle.

[Edit - July 2015 - 3D Systems has now released a water-soluble filament for home printing. This type of material has been a challenge to create because home printers are not typically enclosed, making it hard to control the temperature, and therefore expansion, of the two different materials (build and soluble support). Another limitation was the caustic chemicals required. Makerbot has been selling a material that was soluble in limonene (that orange-smelling cleaning solvent), but hadn't been marketing it loudly since it was tricky to work with. The new "Infinity" material apparently needs only regular water and washes away in about 15 minutes! A huge change from the 10-hour cleanings that have been standard.

This new material is available only in a cartridge for the Cube Pro. I do have access to one, and I am interested to give the new 3D Systems material a try in the coming months.]

ExOne’s ProMetal 3D Printing

One of my favorite types of 3D printing is the 420Stainless/bronze composite from ExOne. It’s a powder-based process that is very similar to the Z-corp (Now owned by 3D Systems) plaster printers. The processes fall under the same 3D printing patent licensed from MIT. An organic binder “glues” the powder together, and a series of carefully developed processing steps burn out the binder and replace the voids in the powder with bronze. This is an odd mix, since these metals are not very similar. You could not weld them, and this is not an alloy, but a mottled mix of about 60% steel and 40% bronze. Here is a close up of a polished ring:

The metal grains vary in size, but they look about about 25-50 microns in diameter. The crevice in the image is a layer boundary. The polishing process removes projecting roughness, but is not aggressive enough to remove depressions. The material and process produce a very nice aged, textured look. There is always a small flat spot on a model where a stem allowed bronze to flow into the part, but they are much more free of defect than raw DMLS parts, and the price is far less. Aside from the pleasing appearance, the material is resistant to oxidation and very strong (about the same as structural steel).

The metal printed Time Keeper, available customized on Shapeways

The mixed bronze gives the metal a slightly warmer hue than regular steel, and depending on some variables in the process, can come out mildly golden in color. I was curious about the composition of the metal, and measured it with an X-ray spectrometer. The elemental composition in the sample I took was:

Iron 45.00%, Copper 40.30%, Chromium 9.97%, Tin 3.58%, Cobalt 0.58%, Manganese 0.31%, Silver 0.17%, Palladium, 0.05%, Nickel 0.02%

Not much nickel, surprisingly. This mixture has a lot of chromium, but not more than typical stainless steel. The lack of nickel interesting to me partly because, apart from being a common component of stainless steel, nickel works well with copper, the main non-ferrous component in the material, so this is the opposite of what I would have guessed. ExOne has a lot of variations on their process, and can do huge parts up to a meter square, weighing hundreds of pounds. Using this material for years, I keep finding more and more good uses for it. Unfortunately this process needs huge vacuum ovens, so we won’t be doing this at home, but the number of installations is increasing, and even Shapeways has plans to purchase their own setup eventually.

UB Gymnastics intro video in production

The Purple Knights gymnastics team at the University of Bridgeport has won an incredible five consecutive championships in both national and regional titles over the last five years. Ten in five years- an amazing record! They deserve a high-quality intro video to represent them online and at meets, so I’m doing my best to put together some great content to show off their skills. We did a ton of work during the first day of production earlier this month. While I was prepared with cameras and lighting, I didn’t actually know how many people were on the team, so was a little surprised when 31 gymnasts filed into the studio.

In about five hours we did six group shots, nine solo, and three pairs. Of course it was busy, but I was amazed at our productivity considering the difficulty of coordinating so many people. The discipline and team-work they bring to their sport was equally well applied in this case. This little army can array themselves in requested configurations in a matter of moments with very little direction. What a pleasure to work with!

Senior gymnast Erin Turner, who is my motion-graphics student, is directing choreography. I managed equipment (grip) and technical requirements for the shots. We used a combination of a high-speed camera shooting at 3k (7 Megapixel) 30fps, along with an HD camera for pre-roll and post-roll on each shot, as well as a DSLR for stills. Junior gymnast Chisaki Hagata assisted with camera operation.

Junior Knights Chisaki, Sasha, and Caitlyn

Jenna and Zahra. They look so sweet, but make them laugh and it's like BOOM! Monster six-pack abs. This crew of athletes is in incredible shape.

Senior Knights. This is what is known as a "Swerve", apparently.

For the remaining action shots we are moving to a much larger (and better quality) green-screen, and doing a lot within their practice space. There’s much more to this project, and the final version is months away, but I’m happy to say this is a personal record for me for scene complexity. 31 Gymnasts in choreographed motion shots make the Morning Star look simple by comparison. Go Purple Knights!


The Most Metal Moment in 3D Printing

The Morning Star is an an incarnation of beauty and danger. It is a 3D-printed sculpture of wood and steel, built by myself in collaboration with ExOne. It weighs about 15 pounds. The sphere of points is about 7.5 inches in diameter. It was printed in four pieces, and the chain portion was printed all at once. The craftsmen at ExOne polished up the points and gave it a nice dark patina for an aged look. The handle was CNC cut from mahogany in five radial sections. The base was CNC cut from oak. Both wood sections were finished with natural oils.

The spike ball design, created in Wings3D

The raw printed parts


Attaching the printed chain

Carefully brazing the chain

Polishing the points

Applying the dark patina

Milling the handle

The completed Morning star on its display base

The Morning Star was featured in the art gallery at the Rapid 3D-printing Conference. It got a great response, and I’m proud to say it was the only piece without a “Do Not Touch” sign. In fact, I ensured there was a signing asking for interaction- this is tactile art!

Afterward, I had a concept to have this brutal piece, made of one of the strongest 3D-printed materials, interact with one of the weakest materials- uninfiltrated Zcorp prints made of gypsum powder. Without reinforcing resin, those parts are very fragile and take great care to move without damage. I created a mesh of the Skull from the Visible Human dataset, and shaded reddish brown it with ambient occlusion in Meshlab. This darkened the crevices and made the entire inside dark red. The skull is life-size and took a lot of work to empty the loose powder from the small holes.

From there, I had a plan to modify the greenhouse in my backyard into a Smash House. I credit Whit, my roommate at the time, for the creative name for this structure dedicated to smashing things with a big metal spike ball.

Welcome to the Smash House

The side of the greenhouse was cut away, the bare frame was painted firecracker red, and a platform was built on the side to mount several cameras. I bought a special camera capable of filming up to 1000 frames per second, though it was used in the 240 fps mode to maintain decent resolution. A hinged apparatus was built to support the morning star, and also to mount a first-person view camera. I had a few friends over to assist in setup and filming.

Right before the smash, I spritzed the skull with water to further reduce its strength, increase its weight, and mitigate dust from the impact. The skull was aligned just off-center so more of the face would be visible in the shot. The ball was aligned just above the lower jaw in the hope that it would remain there as the top of the skull was obliterated. It worked perfectly.


The shot could not have gone off any better. The face was pulverized, leaving the broken lower jaw almost where it stood. The skull tilted backward just as the lowest point wedged it against the ground. The point split it right down the center (along the grain direction), and the two halves of the cranium were sent flying in opposite directions. Smash.

The beautiful shots from five different cameras were assembled into a video, shown below.

Morning Star – The Most Metal Moment in 3D Printing

Thanks to ExOne and everyone else who helped me on this project, which may very well be the most Metal moment in 3D printing.

The 3D-printed Bra

Mardell models a 3D printed top with flexible elastomeric cups

3D printing is perfect for creating items perfectly fit for one person. It has already been applied successfully for prosthetic limbs, joint implantsorthopedic implants and inserts, orthotics, orthodontics, hearing aids, and many more advanced medical applications. Now that people with those rarer conditions have been helped, it’s time for 3D printing to move into applications that help the masses. 75–85% of women who wear bras are wearing the wrong size. By combining 3D scanning, custom software, and 3D printing, millions of women can live more comfortably. I am collaborating with two female industrial designers in Brooklyn who are working on just such a project, and I’m working on exploring a variety of other potential problems and solutions. Using scanning to determine size is very easy, but am taking on the much harder problem of matching and creating the desired curvature and structure. On September 21st, I showed an example design at World Maker Faire in New York that featured 3D-printed elastomeric cups. They are perfectly fit to the wearer using 3D scanning. In this case, the natural shape was ideal, and the function was only to support and preserve, with no shaping required. In cases where a sculpting of form is desired, there is an opportunity for benefit, but a fairly complicated geometry problem to achieve the perfect fit and comfort. I’m making good progress, and this project is tied in with others I’m working on, so expect to hear more about it very shortly.

3D Laser-machining of Acrylic

I have been using an Epilog laser cutter in an unconventional way lately, using it’s raster imaging mode to vaporize materials using repeated passes in an attempt to reproduce fine scale shapes from a “displacement map” image (similar to engraving, just much deeper with predictable dimensions). The most noticeable issue is that, at the 40-watt power level of the machine I am using, the acrylic material is not propelled away from the work surface in the way that high-energy lasers can do. With powerful pulse lasers, very fine cuts can be made in even metals, because the material is instantly vaporized and flies away quickly due to the expansion of the gases. This leaves very little debris at the cut, and does not allow time for the heat to propagate to nearby material, localizing the effects only to the intended area.

You can see the main problem here is that the vaporized material cannot be removed from the area quickly enough. Even with an active vapor-curtain to remove smoke, much of the material still ends up condensing back onto the surface, where it interferes with subsequent passes. There is also some non-linearity in the cut depth (the curvature of the ramp), most likely due to the short focal depth of the laser. This can be compensated for by either shifting the platform upward between passes, or by applying a lookup-table to the gradient to normalize the cutting response. There is also some waviness in the depth that appears to be from vibration in the carriage as it scans over the surface.

Here I attempted a laser-machined acrylic box that needs no assembly, only a heating stage to slump the pieces into position. Note that in addition to the miter-cut edges to join the walls, there are also channels cut in the sides to allow a top to slide into place. After the laser does its work, the acrylic  “snow” is cleaned from the piece. It is then flipped over, supported on the inside of the bottom surface, and heated until the walls swing down into position.

Flowing Forms – Experimentation in 3D Printed Wearable Tech

3D printing creates perfectly adapted forms with unlimited complexity. It follows that the ideal applications for it should play on its strengths, where using other approaches would be difficult or impossible. One of the major promises of using 3D printing for wearable designs is that is can reduce or eliminate the extensive labor required for assembly. When it comes to functional apparel that integrates wiring, fluid lines, air-flow, mechanical devices or fasteners, having everything produced at once is a huge advantage. The sections can be produced separately so the printer does not have to be the size of a person. Correctly sized, integrated fittings hold the tubes in place.

Body-conforming mesh topology derived from a 3D scan

Some experiments I have in the works are designed to integrate pathways for air/fluid or wiring, and are designed to do so without a lot of manual modeling. The path of the channel is derived from the 3D geometry of the scanned body, so the tubing lines follow the body curvature exactly. There are also some interesting aesthetic possibilities offered by these new structures, which can become part of the design rather than being tacked on top of it or covered by it. The designs are inherently organic. These first attempts look like internal organs more than something produced by a machine.

Inside surface of the tubing study

There are a lot of possibilities for building functional structures using these techniques. The most accessible and easily applied are for cooling and ventilation applications, but after some successful prototypes, the applications will be extended to channels for EL-wire or fiber optic lighting, then wiring, and finally liquids, which I anticipate to be the most challenging. Current production processes for materials that are appropriate structurally also require some access to remove support material, so some advancement in materials, processes, or both must be developed for practical transfer of liquids.