## 4 Discussion
### Analysis of the Reconstruction Process and Additive Manufacturing of Models  
Currently, several solutions have been presented in the literature to improve the reconstruction of the geometry of the anatomical structure. These processes combine with the development of algorithms to minimize the impact of metallic artifacts [57], improve the spatial resolution of DICOM data [25], and improve the accuracy of the segmentation process [61]. The publication [25] describes a procedure developed to improve the accuracy \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{3}{*}{**Parameters**} & \multicolumn{4}{c}{**Surface Roughness on the Part of the Pelvis Model Manufactured in One Piece,**} \\  & & \multicolumn{2}{c}{**Normal Vector of the Acetalbumin Area at a Significant Angle to the Z Axis**} \\ \cline{3-5}  & & **Along Applied** & **From the Side of the Surface Contact with** & **In the Acetalbumin Area** \\ \hline \multirow{3}{*}{Sa} & Mean & 48.17 μm & 201.96 μm & 52.08 μm \\ \cline{2-5}  & Std. Dev. & 13.70 μm & 24.44 μm & 5.76 μm \\ \hline \multirow{3}{*}{Sq} & Mean & 58.59 μm & 243.86 μm & 65.77 μm \\ \cline{2-5}  & Std. Dev. & 16.39 μm & 28.48 μm & 7.60 μm \\ \hline \multirow{3}{*}{Spk + Sk + Svk} & Mean & 245.45 μm & 1028.09 μm & 307.21 μm \\ \cline{2-5}  & Std. Dev. & 71.11 μm & 103.03 μm & 36.71 μm \\ \hline \multirow{3}{*}{Sa} & \multicolumn{4}{c}{Surface roughness on an acetalbumin model,} \\  & & \multicolumn{2}{c}{normal vector of the acetalbumin area almost parallel to the Z axis} \\ \hline \multirow{3}{*}{Sa} & Mean & 29.29 μm & 160.64 μm & 85.21 μm \\ \cline{2-5}  & Std. Dev. & 2.08 μm & 22.09 μm & 8.34 μm \\ \hline \multirow{3}{*}{Sq} & Mean & 36.04 μm & 192.32 μm & 102.45 μm \\ \cline{2-5}  & Std. Dev. & 2.76 μm & 25.68 μm & 11.15 μm \\ \hline \multirow{3}{*}{Spk + Sk + Svk} & Mean & 149.94 μm & 768.75 μm & 427.96 μm \\ \cline{2-5}  & Std. Dev. & 17.96 μm & 74.18 μm & 62.84 μm \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Averaged surface roughness results were obtained from measurements using an Alicona InfiniteFocusG4. Figure 23: 3D and 2D visualization of surface roughness on an acetabulum model measured: (**a**) Along applied layers; (**b**) From the side of the surface contact with the support material; (**c**) In the acetabulum area. of anatomical structures within the hip joint. The publication focuses mainly on segmenting implant structures, the head, and the femoral shaft. Since surgical planning often requires the complete development of the left or right side of the pelvic bone. Precise reconstruction of this area is essential [62; 63; 64]. To enhance the procedure in publication [25], an algorithm was developed to improve the segmentation capabilities of the three sub-areas, including the critical acetabulum. This involved using data interpolation and local thresholding to establish precise segmentation thresholds expressed in HU units. In manufacturing the models, we focused on nozzle and work platform temperature, layer thickness, manufacturing speed, model orientation in the 3D printer space, and the degree of model filling. The parameters indicated are the basic and most important ones. They are often readily available in software dedicated to the process and device. A filling density of 80% in the form of a grid is intended to simulate a similar resistance across the entire volume of the anatomical structure when instruments are being prepared for surgery. The layer height of 0.3 mm speeds up the 3D printing process and is sufficient to mimic the anatomical structure, while the stepped effect is low. The temperatures of the extruder and the working table were chosen according to the experience of the machine operator and the manufacturer's recommendations. The print speed of 80 mm/s is not high and could be higher, but it is correct for cooling the research model on the build layer and guarantees the correctness of the additive process. As the accuracy of the anatomical structure models is in the range of approx. \(\pm\)0.3 mm, we used a layer thickness of 0.3 mm.