F*ck them orthoses

Custom made orthopaedical orthosis for the ankle joint fracture

Every cloud has a silver lining. Even an injury can act as an impulse to create an innovative product combining computational design, fashion and medical use. We engaged the client in the entire process. With parametric design approach and 3D scanning, the client became the co-author of his own medical device – a custom-made orthopaedical orthosis for his ankle joint fracture.

Each of us is unique. Each person has different needs and preferences. When it comes to medical devices, their appearance had never been the main point of interest. We, however, think that medical devices like orthoses and splints should not only reflect anatomical parameters and ergonomics, but also the lifestyle, preferences and taste of the user. A great design increases the acceptance of the medical device and the satisfaction of the patient and therefore also the whole efficiency of the product and medical treatment.

Design is for us a collaborative process. The most important innovations are created in synergy between specialists from different fields. This is why we incorporated 3D scanning and digital fabrication into our computational design process, combining our expertise of Subdigital with the competences of Photoneo, Invent Medical and one3D. We took the challenge to set up the right strategy and technology that embraces the designer touch of Subdigital to create a fashionable, yet high-performance product.

3D scanning

Stage one

In this project, Photoneo 3D Vision tested the high detail scanning of a human body for medical purposes. Photoneo used the MotionCam-3D camera of their own production for the body scan (patient´s right leg, from the knee to fingertips). It was an obvious choice because of the need to scan the whole surface of the foot, including the calf and foot in one 360-degree shot. While scanning, the camera was moved around the leg. The Photoneo’s own developed MotionCam-3D is the only camera in the world that is able to scan moving scenes in high quality and resolution.

Photoneo developed a special software to be paired with their camera, which, instead of a point-cloud produces a “mesh in real time” – a 3D model with continuous surface that does not need any other postproduction. The output of such scanning and meshing process is a high-resolution meshed surface 3D model of the leg available in the STL file format.

The use of such processes for medical purposes has great advantages. Among others, it is mainly the speed and simplicity of the process. In good conditions, the model is ready in 1-2 minutes and there are no limitations or special procedures patients should undergo before the scanning.

The combination of the MotionCam-3D and the special software allows the scanning of any object and surface – it is widely useable in several industries: from the car industry and logistics to food industry and medicine.

DESIGN

Stage two

Subdigital studio´s main focus is computational design. We work mainly with the Rhinoceros 3D and Grasshopper software, which allow us to design using complex parametric models and simulations. The splint project was a great chance to present the capacities of the methods and tools we use. We went through multiple stages, from processing the 3D scanned model, through parametric analysis and modeling and the generative design of the form to optimization for the fabrication.

The basic concept of the design was to use physics models and simulations to evaluate the forces in the shell of the splint and the transformation of these parameters to forms. Such high-performance and visually complex and appealing detailed forms can be produced only by using the 3D printing technology.

The first part of our work was to process the 3D scanned data – from the mesh model to the clean mathematically defined (NURBS) surface to be evaluated and processed further. Photoneo scanned the leg multiple times to ensure the highest precision possible, each time aiming for a certain part of the calf, ankle or foot. That meant that the 3D scan consisted of multiple separate mesh models. To get a single complete model that would be as precise as possible, we cut the mesh geometries perpendicularly to the axis of the model. We spread these resulting cut-curves on the plane and consequently rebuilt each set of sections to make a clean and mathematically valid curve. When placing these sections back in the position around the axis, we get a precise wireframe model and a valid closed surface.

The mathematically defined model of the leg (NURBS geometry) was trimmed to the shape of the shell structure around the calf, heel and ankles – areas where the structure is necessary for the functionality of the splint. This shell was ready for structural evaluation in the Millipede plugin for Rhinoceros 3D and Grasshopper software. We calculated the precise values for bending, stress and pressure flows in the shell. This process did not generate the 3D printable geometry yet, but we calculated information and parameters (stresslines and force intensities in certain places). Based on those, we are able to generate a highly performative 3D printable shape.

Thanks to the consultation with specialists of Invent Medical, we were able to set up the right system of forces and pressures acting on the shell of the splint. In our particular case, it was necessary to fix and reinforce the foot in case of accidental encumbrance and secure it to avoid twisting and rotations in the ankle. We acted with forces on certain areas of the shell. The result was a parametric structural analysis.

The basic principle of computational design is the transformation of parameters to forms and shapes using algorithms. Since this project was no different, we used the output of the structural analyses as inputs to generate the form in multiple layers. The inner layer was created using a method consisting of wrapping the structure into a mesh volume. Smoothing of this mesh generates a form that appears as a delicate porous etched surface. The density of the structure reacts to the intensity of forces – pressure and bending in the splint shell. It is generated to be thicker and stronger where necessary, and on the contrary, thinner and more porous to spare the weight, reduce the use of material and achieve flexibility and breathability where possible.

The outer layer was generated as a transformation of curves describing the force-courses in the splint under the pressure. Ribbed structure formed by these curves reinforces the splint to the bending in the most important directions. In others, the structure keeps its flexibility to ensure comfort for the user. Alongside the force-shaped ribs we generated other sets of ribbed structure with various purposes. Perimeter of the splint is edged with the oval rib to ensure comfort without any padding. We also shaped the structure itself to contain openings for elastic straps to fasten the splint when worn.

These openings are edged with the same type of ribs as the whole outer structure and are organically connected to them. The inner layer of the splint gives a space to these utilitarian parts. The whole structure is thus generated as a one coherent unit.

Using physical simulations and analyses helped us to achieve high strength with minimal material use. We created a splint that is not only anatomically and medically optimal, but also his lifestyle and aesthetic preferences.

3D print

Stage three

One3D materialized the designed structure of the splint made of solid, flexible and durable material. It was printed using polyamide powder PA2200 stiffened by the laser sintering method. This material has ideal properties for such medical use – it is very solid and stiff, mechanically and chemically durable and safe in contact with the skin and food. From the designer’s point of view, it has great possibilities of use due the high detail of print – structural rib parts up to 2mm´s detail, shell structures up to 1.5mm thin with the smallest printable detail of 0.6mm. Thanks to these printing possibilities, we were able to work with high level of detail and aesthetic intricacy on the smallest scale. By optimizing the structure to the parameters of the material, we achieved a significant reduction of used material and printing time while maintaining all the desired properties of the splint.

Branding

Stage four

The last final touches of the design were produced by designer and artist Martin Mikulka from Banned Studios. The fine black detail of the structure was prepared to be painted in order to follow the visual identity of the F*CK THEM creative house. This brand is currently working with the motives of fire and flames – the logo of F*CK THEM was visually set on fire. This final graphics layer turned the highly performative and ergonomic design into a fashionable merch accessory.

Summary

We created an object which combines contemporary digital aesthetics of parametric design, high-performance medical design, technologies of 3D print and 3D scan together with fashion and art. This project is a perfect example of the potential of new tools and new approaches to design. In collaboration with teams of experts from Photoneo 3D Vision, Invent Medical and One3D, we created this unique product for F*CK THEM.

Computational methods generating complex patterns, structures and materials are used for instance in sports fashion apparel (NIKE flyknit) for their performance. At the same time, they appear as concepts in haute couture for their unique contemporary visuality and artistic relevance (Iris van Herpen, Neri Oxman). This kind of contemplation between technology and art is very close to our values, so we gladly combined it with the 3D scanning and precise 3D printing to produce this high-performance fashion accessory that serves as medical device.

We would like to thank Michal Novotny (Yaksha, F*CK THEM), Michal Blazek (Photoneo3D Vision), Invent Medical, Tomáš Klempa (one3D) and Martin Mikula (Banned Studios) for cooperation. © July 2020