## 3 Results and Discussion
### Assessment of Surface Roughness Measurement in Test Specimens  
All analyses were performed in the MeasureSuite 5.3.4 software using the Alicona device. The goal was to analyze and assess the possibility of surface roughness scanning in 3D-printed specimens with lattice filling and a gyroid structure. The specimen's ground plan was square, with a size 35 mm \(\times\) 35 mm. The process of roughness measurement in the experimental specimens is described in Section 2.3, and we used a data processing and assessment methodology, as shown in Figure 3. Before starting the measurement, it was necessary to remove supports, unwanted strings, and brims. Samples produced by FDM technology presented problems with regard to detailed scanning due to a large amount of unwanted strings, which affected the surface roughness calculations. This is why the roughness parameters Ra, Rz, Rv, Rp were determined. Tables 1-5 show selective averages listed from a statistical file of measured data. The measurement was conducted on the edges of the specimen's surface. It was impossible to perform measurements in the specimen's center due to the string. The whole measurement was set to 10x optical zoom, while the brightness and contrast changed depending on the specimen's reflection and the geometry of the measured point. Brightness and contrast are the primary settings for the scanning of a specimen's surface. This information cannot be found in a table, as the experience and expertise of the researcher has a great influence. Each specimen's measurement was performed five times to enable statistical analyses of the measurements. Figures 19-23 show the scans of the individual gyroid and lattice experimental specimens' surfaces. The measured roughness parameters can be seen in Table 8.  
Figure 18: Illustration of deviations when comparing manufactured black specimens (FDM method) to the CAD model: (**a**) lattice; (**b**) gyroid. Figure 19: Red gyroid specimen (FDM method)—scan from the upper side. Figure 20: Gray gyroid specimen (SLS method)—scan from the upper side. The specimen in Figure 19 features a particularly high roughness parameter \(R_{a}\), while Table 8 demonstrates that the Rz parameter (red gyroid specimen), with the arithmetic average value = 137.190 \(\upmu\)m, has the largest voids against the central straight line of all measurements' arithmetic average. The experimental red lattice specimen could not be scanned to measure surface roughness parameter R due to the large amount of string and poor printing quality, with reflections causing a set of points not to be scanned with suitable quality to be assessed. The Alicona creates a scanned model by stacking individual images in the \"Z\" axis. In this  
Figure 23: Black lattice specimen (FDM method)—scan from the upper side. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Measured Value \(\overline{x}\) [\(\upmu\)m]**} & \\ \hline
**Parameter** & **Ra** & **Rz** & **Rv** & **Rp** \\ \hline Red gyroid specimen & 31.674 & 137.190 & 103.811 & 73.956 \\ \hline Gray gyroid specimen & 26.125 & 192.579 & 139.540 & 128.952 \\ \hline Gray lattice specimen & 20.990 & 166.473 & 110.237 & 87.113 \\ \hline Black gyroid specimen & 33.546 & 136.884 & 74.998 & 75.569 \\ \hline Black lattice specimen & 45.861 & 316.255 & 242.218 & 132.599 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Measured parameters of roughness. Figure 22: Black gyroid specimen (FDM method)—scan from the upper side. case, it was difficult to create this model because the surface contained a large number of thin strings. The gray lattice and gyroid specimens, manufactured by the SLS method, have more than two-times better surfaces in terms of measured roughness parameter R, and the string does not trigger problems as it does in other specimens manufactured by the FDM method. Moreover, their surfaces present the best appearance, even by subjective observation with the eye. This method was created to compare the two most common methods used to manufacture 3D-printed plastic specimens.