CPT_1 explores water-inspired forms using Stratasys PolyJet technology and Agilus 30. How does this material’s flexibility and durability impact the performance and lifespan of the footwear?
Agilus 30 is a high-performance photopolymer known for its exceptional tear resistance and flexibility, making it suitable for footwear applications. The unique construction of 3D-printed shoes gives them an inherently longer lifespan. Since the shoe is printed as a single piece, there is no need for glue or stitching to hold it together. This reduces potential failure points, resulting in greater durability and an extended lifecycle for CPT_1 and other shoes produced through 3D printing.
Another common issue with traditional footwear is that, once they become dirty and difficult to clean, they are often discarded. However, 3D-printed shoes overcome this problem. Unlike conventional materials that tend to absorb dust, dirt, and odors over time, 3D-printed footwear is easy to clean and does not retain dirt or unpleasant odors, maintaining its appearance and hygiene for longer periods.
Agilus 30 offers a rubber-like finish. What are the specific benefits and limitations of using PolyJet printing for functional footwear prototypes compared to other 3D printing methods like SLS or FDM?
The advantages of using Agilus 30 include the ability to print flexible, multi-colored materials, a unique feature compared to other 3D printing processes. Unlike SLS, FDM, and most SLA technologies, Agilus 30 on Stratasys PolyJet technology can seamlessly print different colors layer by layer. This capability allows for intricate design exploration with color and texture that FDM, SLS, and SLA cannot yet achieve. The level of detail and color fidelity possible with Stratasys PolyJet technology is remarkable, making it ideal for simulating textures, patterns, and colors with unmatched precision.
While Agilus 30 produces a rubber-like finish, this characteristic should not necessarily be seen as a limitation. Instead, it is a feature of the material that designers can embrace. Rather than resisting the inherent properties of a material, it is often more effective to work with its unique attributes, leveraging them to enhance the design and functionality of the final product.
How do you optimize print orientation and support structures to achieve consistent flexibility and surface quality in complex footwear designs like CPT_1?
One aspect I deeply enjoy about 3D printing is the level of connection and control it provides designers over the final manufacturing output—especially when they have a solid understanding of 3D printing processes. My journey into 3D printing began during my industrial design studies, where I developed a strong foundation in designing for 3D printing and manufacturing. Through this experience, I gained valuable insights and techniques for optimizing 3D models, such as minimizing supports and enhancing surface quality.
I prefer to fully understand and operate the machinery I work with, as it provides a clear sense of both the technology's capabilities and limitations. This intimate knowledge allows me to push boundaries and explore the full potential of the manufacturing process. However, working with different technologies, such as PolyJet printing, requires a slightly different approach. While I usually oversee and control the entire output process with my own equipment, in this case, I collaborated with a machine technician, which meant I did not have direct control over every aspect of the printing process.
Despite this, I applied key principles of designing for manufacturing to the 3D model of the shoe. By doing so, the model required minimal adjustments from the technician to optimize surface quality, support structures, and orientation. When designing for 3D printing, some general rules apply, such as ensuring that overhangs do not exceed 45 degrees. Additionally, depending on the specific 3D printing process, considerations like material thickness for walls, infill, and supports are crucial for achieving optimal results.
When working with additive manufacturing, how do you ensure dimensional accuracy and fit in footwear, especially considering shrinkage or deformation during post-processing?
Depending on the specific 3D printing process—such as SLS, FDM, or SLA—manufacturing tolerances typically range between 0.2 mm and 0.5 mm for desktop FDM printers. While these tolerances may be too large for industries requiring extreme precision, such as aerospace, they are generally acceptable for footwear design. Ensuring proper dimensional accuracy and fit in footwear is particularly intriguing to me. Each person has their own subjective expectation of how shoes should feel, which may not align with the designer’s vision, the manufacturer’s standards, or even the optimal biomechanics for their feet.
Zellerfeld provides an excellent example of how 3D printing can revolutionize fit customization. When they launched, they allowed customers to choose whether their footwear fit tight, neutral, or loose. Since their shoes were based on 3D scans, the company had the flexibility to tailor the fit. However, these terms—tight, neutral, loose—are inherently subjective and vary greatly from person to person. As 3D printing advances, I believe there will be a growing need for more precise systems to define and measure fit, allowing for truly individualized footwear.
This isn’t entirely different from traditional manufacturing, as conventional footwear is also subject to dimensional changes due to shrinkage, deformation, UV exposure, wear and tear, and general use. One challenge with 3D printing is managing these variations, particularly with advanced materials like Carbon's EPU Pro. This material is a dual-cure elastomer capable of a wide range of mechanical responses, making it ideal for lattice products and functional parts. Additionally, Carbon's dynamic foaming technology expands the material to its true size during curing. Carbon mitigates these issues through its integrated software, which optimizes production for complex materials like EPU Pro.
Although I have not yet worked with Carbon’s technology, I’m excited to explore its potential and incorporate it into my future projects. Their innovations could greatly enhance both the design and performance of 3D-printed footwear.
O°BLOOM is inspired by mycelium networks. How do natural growth patterns influence the design language and structural elements of the footwear?
Nature is an extraordinary force, equipped with a built-in survival instinct and biological clock—traits that seem diminished in humans. The primary goal of organisms in nature is to reproduce and ensure the survival of their species. To achieve this, nature operates with remarkable efficiency, conserving resources and crafting systems and structures in the smartest possible way.
A fascinating study exemplifies this concept. A team of engineers in Japan, designing the country’s rail system, drew inspiration from slime molds to map out pathways between major urban centers. In their experiment, researchers placed oat flakes on a dish to represent key Japanese cities around Tokyo. Initially, the slime mold expanded in all directions, but it soon optimized its growth, reinforcing tunnels and connections directly between the oat flakes. This pattern became the blueprint for the subway routes connecting the cities.
Similarly, mycelium—another network in the fungal world—exhibits a complex and dynamic system of communication. These mycelial networks function like an information highway, enabling trees in a forest to exchange nutrients, defense signals, and allochemicals. From a social perspective, footwear and fashion serve a comparable role, acting as a form of communication that bridges diverse backgrounds. Just as fungal networks connect forests, I view footwear as a medium that connects people.
Footwear doesn’t just connect people to one another; it serves as the crucial link between the body and the ground. Your feet are the foundation of your body, and what you wear on them directly impacts this connection to the Earth. This relationship profoundly affects your joints, movement, and overall well-being. A weak or improper connection to the ground can lead to structural imbalances, resulting in joint pain and long-term movement issues. Restoring and maintaining a strong, stable foundation between your feet and the ground is essential for promoting healthy movement patterns and ensuring pain-free joints.
Beyond the social and physical implications, I’m fascinated by how mycelium structures grow and adapt. Patterns in nature are often replicated globally, appearing in animals, plants, and landscapes. These natural patterns can also be simulated using mathematical models, which, as a computational designer, I find deeply compelling. Examples of such patterns include the Fibonacci sequence, fractals, logarithmic spirals, radial and bilateral symmetry, Voronoi patterns, and five-fold symmetry.
Take, for instance, the Fibonacci spiral, which can be observed in the cross-section of a seashell, the arrangement of pinecone scales, the growth of aloe leaves, and the structure of many other plants. Advanced software tools allow designers to harness the power of these mathematical patterns, simulating and replicating natural forms algorithmically. One commonly used algorithm in this field is the reaction-diffusion model.
It’s also possible to modify algorithms by introducing attractors, similar to the role oat flakes played in the slime mold simulation. Applying this concept to the growth of mycelium in shoe design, attractors can be strategically placed at points where the shoe requires the most support. This allows for the simulation of structural reinforcement through the natural growth networks of mycelium, resulting in a design that is both functional and biologically inspired.
O°BLOOM uses PHAs (polyhydroxyalkanoates), a biodegradable polymer. How does PHA compare to TPU or other commonly used polymers in terms of durability, flexibility, and biodegradability?
O°BLOOM utilizes PHAs (polyhydroxyalkanoates) instead of TPU, and the comparison between the two highlights a clear sustainability advantage. PHAs are fully biodegradable, as demonstrated by the O° platform developed by Neri Oxman and her team at Oxman Official, which showcases a time-lapse of a shoe degrading within six weeks. In contrast, Bio-TPU available on the market takes approximately 3–5 years to break down.
Beyond its environmental benefits, PHA offers remarkable flexibility in material application. It can be spun into threads for knit uppers and also formed into 3D-printable filaments that can be sprayed or extruded onto surfaces. To my knowledge, TPU lacks this level of adaptability across material applications, making PHA a more innovative and sustainable choice for advanced design.
You’ve mentioned hot spraying and flat/circular knitting as part of the production process. Can you elaborate on the role of hot spraying in creating seamless footwear uppers? How does it contribute to the shoe's structural integrity?
When constructing shoes using hot spray and circular knitting, the hot spray plays a crucial role in achieving glueless footwear construction. The circular knitting creates the upper part of the shoe, functioning much like a sock. The hot spray is then directly applied to this knitted upper using 6-axis robotic arms. This process eliminates the need for glue, as the spray material itself adheres to the sock, serving both as the bonding agent and the structural component.
The way the hot spray is applied can significantly affect the upper's structure and influence how the foot moves within the shoe. By leveraging programmable algorithms, the hot spray can create various geometries, patterns, and support tailored to specific applications—whether for fashion-forward designs or more minimalist, barefoot-style footwear.
Lifecycle design is a core part of O°BLOOM. How do you tackle the challenge of wear and tear in products that are meant to biodegrade after use? Is there a risk of premature degradation during the product's lifecycle?
Life cycle design is a key focus of the O°BLOOM footwear collection, but incorporating it into the textile industry presents significant challenges. At its core, life cycle design is an approach that considers the entire journey of a product—from its creation to its eventual disposal, whatever form that may take.
There are various strategies for minimizing waste at the end of a product's life. Recycling is one of the most common solutions, but it places the responsibility on the consumer to complete the life cycle, which often doesn’t happen consistently. Another approach involves using biodegradable materials instead of relying solely on recycling. However, biodegradability comes with its own challenges, such as the risk of premature degradation, which also demands careful consumer responsibility.
I believe we, as consumers, share a collective responsibility that isn’t being fully embraced. Many products are marketed as sustainable, but the reality can vary greatly depending on the specific aspect of sustainability being highlighted. While the development of new biomaterials is exciting and promising, true sustainability requires a holistic and responsible approach. It’s about thoughtfully managing every stage of the product’s life cycle, from beginning to end. Ultimately, sustainability comes down to responsibility.
The TENDON project focuses on mimicking foot anatomy for comfort and performance. How do you translate biological movement patterns into mechanical properties when designing footwear components?
Tendon is a project inspired by the anatomy of the foot, specifically the tendons, designed to offer support and comfort while promoting natural foot function. Many modern footwear designs incorporate technologies—such as arch support and ultra-cushioned soles—that, although well-intentioned, often disrupt the foot's natural mechanics over time.
One major issue with modern footwear is its reliance on artificial arch support. This compromises the foot's strength by reducing the activity of the muscles responsible for maintaining the arch, leading to weakened muscles and, ultimately, flat feet. The arch of the foot is a dynamic structure designed to collapse and spring back with each step, contributing to efficient movement and shock absorption. By preventing the arch from collapsing, arch support forces the body to compensate, placing additional strain on joints like the knees and hips.
The Tendon concept explores biomimetic solutions by modeling external supports after the tendons on the underside of the foot. Since prolonged use of ultra-cushioned shoes weakens the foot’s muscles and tendons, Tendon introduces external mechanical supports that align with the body’s natural pathways. These supports do not replace the foot’s function; rather, they assist in rebuilding strength and restoring control. The concept allows the arch to form naturally during the walking cycle, helping the wearer regain foot strength, restore the foundation of their body, and enable freer, more natural movement.
Looking at the future of sustainable footwear, how do you see biofabricated materials (like PHAs) evolving in terms of mechanical performance and cost-efficiency compared to synthetic polymers currently dominating the industry?
I am genuinely enthusiastic about the future of sustainable footwear. It’s fascinating to observe the innovative and unique approaches manufacturers and innovators are adopting to address sustainability challenges. While it remains uncertain whether biofabricated materials will surpass synthetic polymers in dominance, I do see a promising shift toward genuine sustainable practices. This stands in contrast to past trends, where companies often engaged in "greenwashing"—promoting products as sustainable without substantial evidence to attract market attention.
One challenge biofabricated materials face is the MAYA (Most Advanced Yet Acceptable) principle. For consumers, this raises valid concerns: "If the material is designed to degrade, will it degrade prematurely? Will I get the full value and use from this product? Does it require additional care and maintenance?" These are important questions that can influence consumer confidence in adopting such materials.
At its core, I believe sustainability hinges on responsibility. Biofabricated materials may require consumers to adopt more intentional care practices to ensure product longevity and avoid premature degradation. Unfortunately, many consumers desire sustainability without the accompanying responsibility—a paradox that undermines true sustainability.
Despite these challenges, I am optimistic. As biofabricated materials become more prevalent and familiar in the market, their mechanical performance and cost are likely to improve, eventually rivaling those of synthetic materials. This evolution has the potential to redefine the footwear industry and drive meaningful progress in sustainability.
Are there any emerging additive manufacturing techniques you’re excited to explore that could further revolutionize footwear production, particularly in performance wear?
A significant manufacturing challenge associated with additive manufacturing techniques is managing overhangs in the parts being created. Typically, features that extend or hang out at angles greater than 45° are difficult for most 3D printers to produce without the addition of supports. While incorporating supports is not inherently problematic, it does come with drawbacks, such as increased print time and the use of additional material, much of which is discarded after printing.
An innovative solution to this challenge has been developed by MIT’s International Design Center. Their process effectively eliminates the need for traditional supports by printing within a vat of support material. This approach not only addresses the issue of overhangs but also optimizes material usage and efficiency, showcasing a breakthrough in additive manufacturing techniques.
MIT’s International Design Center has developed an innovative solution to this challenge by introducing a process that eliminates the need for traditional supports. Instead of relying on external supports, the technique involves printing directly within a vat of support material. This method not only addresses the issue of overhangs but also enhances material efficiency and reduces waste, representing a significant advancement in additive manufacturing technology.
Rapid Liquid Printing (RLP) offers a groundbreaking approach to additive manufacturing by depositing material within a container of dense gel. The gel provides support for the deposited material, preventing collapse or drooping, as its density is greater than that of the material being printed. This innovative method unlocks new possibilities for complex geometries that were previously unattainable with traditional additive manufacturing processes.
Beyond geometric freedom, RLP addresses key limitations of speed, size, and material versatility. Researchers at MIT highlight that this technology can fabricate full-scale furniture in just minutes, utilizing a variety of industrial liquid materials such as rubber, foam, and plastic. This versatility makes Rapid Liquid Printing a significant leap forward, opening new horizons in design and manufacturing.
It will be fascinating to explore how Rapid Liquid Printing could be applied to performance footwear, especially in overcoming the weight challenges that have historically been a limitation of additive manufacturing. The development and incorporation of lightweight yet durable materials could revolutionize the design and usability of 3D-printed shoes for runners and athletes alike.
Carbon 3D's EPU Pro materials represent a significant advancement for performance footwear. The integration of design flexibility, weight reduction through foaming agents, and a broad range of Shore hardnesses for optimized cushioning and enhanced strength makes them an ideal candidate for performance running shoes. Furthermore, the silky, suede-like surface texture adds an element of comfort and sophistication, making these materials especially suitable for barefoot or sockless footwear designs, where comfort, durability, and tactile quality are critical.
