# Upper Limb Orthoses: Integrating Topology Optimization and 3D Printing for Custom Fit and Function
## 3 Generating the Design Domain and the Associated FE Model
### 3D Scanning Feature  
For the digital representation of the human anatomy, there are nowadays various methods that can be used, e.g., Computed Tomography--CT, Magnetic Tomography (Magnetic Resonance Imaging--MRI), as well as 3D Scanning technology. Both axial and magnetic tomography offer the possibility of digital representation even of the internal parts of the human anatomy with quite high precision. For the creation of personalized orthoses, the digital representation of the internal morphology of the human anatomy is most of the time not necessary, depending on the anatomic area of interest, and for this reason, the constantly evolving 3D scanning technology plays an important role in this field, as it enables the visualization of only the external surfaces, thus reducing greatly both the data to be obtained and the time to process it to render the final digital model.  
Similar to the methods of axial and magnetic tomography, 3D scanning technology also presents some disadvantages, which include the inability of receiving data with great accuracy on the surfaces of the anatomy characterized by quite complex geometric features (e.g., areas between the fingers on the extreme hand), resulting in either gaps or unwanted convergence of points in the corresponding areas, thus making it necessary to further process the obtained data in order to repair the final model. In addition, another drawback is the presence of noise in the final model due to possible movement of the anatomy during the scanning process, thus necessitating, usually, the use of special custom supports at specific points to avoid unintended movement.  
In this research, the scanning was performed using the EinScan-SE 3D Scanner by Shining 3D\({}^{\text{\textregistered}}\) Tech Co., Hangzhou, China [25]. During the scanning process, the hand was positioned neutrally, aligned at 0\({}^{\circ}\) relative to the two motion axes, with the fingers in a relaxed state resembling the grip on a glass (see Figure 1). This posture facilitated the capture of data in the less visible regions, primarily located between the fingers. The result of each scanned surface, from the whole anatomy of the studied hand, was visible in real time during the scanning process. It is important to note that for optimal connection of the individual scanned surfaces of the hand to create the final model of the hand, the design of some \"guide\" points on it was manually performed, as they were quite distinct from the 3D scanner. The hand remained stationary during the process of scanning each surface, and was then moved in such a way as to obtain data from the remaining parts of the anatomy as necessary. Stabilization of the arm is deemed necessary in order to obtain a good digital model representation of the actual anatomy. For this reason, the use of some supports (Figure 1) was deemed necessary after the first scanning tests, as after the first minutes of the procedure, it was difficult to control the position of the arm, as well as to keep it stationary. The whole process took about 15 min after the first tests were carried out, mainly due to the inability to completely immobilize the hand and the great complexity of the surface to be scanned.