Automating 3D modelling of orthotics and prosthetics with Geomagic Freeform 

Orthotic and prosthetic (O&P) businesses in Germany are under pressure. Requirements and specifications for producing assistive devices are becoming increasingly stringent, a trend that is pushing O&P companies to tighten their spending. The main lever they have for reducing cost is labour time. 

One O&P specialist has found a solution in digital manufacturing. Häussler Technische Orthopädie GmbH in Ulm, Germany specialises in producing orthoses and prostheses and providing rehabilitation and medical technology for the field of homecare. They increased efficiency by replacing traditional plaster casting and conventional manufacturing with digital workflows, including 3D scanning and Geomagic Freeform, which they purchased through Antonius Köster GmbH & Co. KG. With the ambition to empower other O&P businesses to do the same, in 2023 they launched the TOplus brand of tools and services for digital manufacturing in O&P.

3D modelling automated with Geomagic Freeform’s Dynabots
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One of their products is a 3D scanning tool called the TOscan-UE. Together with Geomagic Freeform’s Dynabot automation, this tool constitutes a plug-and-play solution for 3D scanning and modelling of upper extremities. Because the Dynabot automates the process of editing, modelling and preparing the scan data, a Certified Prosthetist Orthotist (CPO) spends much less time on this step. 

This innovation is the brainchild of Alexander Krieger, development engineer at Häussler Technische Orthopädie GmbH and manager of the TOplus product range.  

“The TOscan-UE scanning tool with the Freeform Dynabot provides a simple and straightforward workflow for anyone who is switching to digital manufacturing in O&P,” Krieger says. “With the Dynabot you get a simple workflow for Geomagic Freeform. You play it and, at the end, you have a body model ready for production. The Dynabot simplifies the process so that even beginners can prepare a body model, and advanced users model much faster. Whatever your case, it saves a lot of design time.” 

The way the TOscan-UE system works is simple. First, a patient’s arm is positioned and scanned in the scanning tool. Then the tool is scanned on its own, without the limb. Finally, the two scans are subtracted and modelled inside Geomagic Freeform in an automated and guided process. The result - a clean and complete model of the limb ready for designing an orthosis or prosthesis. 

Streamlining scan data preparation for an assistive device 

The TOscan-UE tool addresses three big challenges with scanning extremities. Firstly, patients tend to move which creates motion artifacts in the scan data. Secondly, patients need to be in the optimal position for their indication. For example, an arm should be in the position with the most grip strength and lowest muscular constraint. Thirdly, the scan is randomly placed within the digital coordinate system of the modelling software. 

Because the limb of the patient is fixed and placed in the optimal functional position with the TOscan-UE, it’s easy to process the scan data. In addition, the tool features a specific target setup to define how scans are positioned in the digital coordinate system inside Geomagic Freeform.

With the scanning complete, Dynabot enters the scene. This is a tool for automating steps inside Geomagic Freeform. The Dynabot that comes with TOscan-UE automatically aligns the scans, smooths out artifacts, adjusts the wrist angle, and guides the user step by step through the modelling process. They get a clean body model that they can use to design the prosthesis or orthosis.  

This innovation is a result of years of experience in digital O&P workflows. Häussler made their first foray into the field in 2017. From the outset, they chose Geomagic Freeform for modelling. It was the most versatile 3D design software on the market, making it well-equipped to handle the diverse array of products and services the O&P company provides. 

Häussler’s workflow can be broken down into three phases. The patient’s body is scanned, the scan data is loaded into Geomagic Freeform, edited and the orthopaedic aid is designed around it. Plaster casting still has a role to play, but only in very specific cases. For example, patients with muscular contraction that is severe and uncontrollable cannot be scanned, so the CPO does a cast of the limb. Even in this situation, the cast is 3D scanned to get the digital body model to produce the orthosis or prosthesis.

Whatever the patient, whatever the device, Häussler aims to bring it into the digital world. This principle is part of their vision for the future of industry. “Our main goal is to implement an evidence-based manufacturing process in O&P. If you ask a CPO to prepare a plaster model for the same body twice, the resulting models are never going to be the same. When you work digitally, you can document the process and reproduce it. This is important for us because we have developed a specific way of designing an orthopaedic device based on our experience of what works. Geomagic Freeform enables us to control that process,” Krieger says. 

Preparing and editing 3D scan data of an arm that will serve as a foundation of an orthosis

A good example is modelling the relief areas for bony structures in a forearm orthosis. It’s good practice to add a few millimetres of free space around the wrist joint to prevent pressure points in the orthosis. Using a conventional approach, it would be difficult to add or remove exactly three millimetres of material. With Geomagic Freeform, it’s possible to emboss the exact amount of material every time.  

“The process of designing an assistive device with Geomagic Freeform is more transparent and controllable. We can standardise it. We get a record of all the changes we made, including the limb model without and with adjustments. We know exactly how each step of the process looked,” Krieger explains. In conventional production, once you change a plaster model, it’s impossible to revert to the original.  

In addition to keeping track of changes, Krieger finds it easier to measure, take pictures and create documentation. He can even design features that are nearly impossible to make conventionally, such as perforation areas.  

As a result, CPOs can do more in the same time span. “Efficiency is 30%-40% higher with Geomagic Freeform than when working the conventional way, mainly because we’ve reduced labour time. Working digitally and using Dynabots allowed us to become much more efficient than with plaster casting,” Krieger adds.  

New Dynabots on the horizon  

Dynabots gave Häussler the keys to simple and streamlined digital workflows. The TOplus tool was the first result of efforts to leverage this for scan data processing. The next frontier is automating 3D modelling and designing of assistive devices.  

The plan for the immediate future are Dynabots for modelling lower limb orthoses and prosthetic sockets. Designing an assistive device requires a deep understanding of material parameters, specifications and production processes, like 3D printing. Häussler will transfer their knowledge of these factors into the paid Dynabots and sell the license to it as a plugin. 

This will lower the barrier for digital workflows in O&P. “You can achieve perfect 3D scanning with the TOplus tools, with its free Dynabot you can model the body, and with the paid Dynabots you will be able to automate the orthosis creation. It’s a straightforward guided process that you can use to grow business,” Krieger concludes.