# Optimising Amber Processing Using 3D Scanning: New Perspectives in Cultural Heritage
## 2 Methodology and Research
### Results of the 3D Scanning Process  
The 3D scanning and subsequent data processing resulted in digital 3D models of the amber specimens. Table 1 presents the outcomes in the form of mesh models and models with applied texture and their measures. Amber 2 was exceptionally difficult to scan due to the high porosity of the surface, which is why it required a larger number of scans. The scans themselves had to take longer than Amber 1 and 3. As a result, for a constant number of scans 30 fps at the same resolution, an approximately three times denser mesh was produced for Amber 2. The mesh analysis of all models showed the same representation of the surface detail of each object. The obtained models serve as digital documentation of amber geometry, enabling the planning of amber processing while taking into account the optimal utilisation of the material, such as verifying cross-sections along defined cutting planes. To present the optimisation process of the processing workflow, the most challenging stone among the available ones was selected--Amber 3. In the vector graphics program Rhinoceros3D, a simplified diamond-shaped model (truncated hexagonal asymmetric bipyramid) was developed for the stone-amber. This model was then copied multiple times, and each copy was scaled down according to a graduated scale. For this purpose, four scaled models were selected. The models of the jewellery were set as solid objects, while the scanned amber model was set as mesh. This allowed for spatial visualisation of the intersecting solids. Figure 8: Post-processing steps, from the left: point cloud of an individual scan, alignment of scans, generated mesh model. In Figure 12, the optimal position of the diamond model within the mesh of the unprocessed amber is observed. The allowances for grinding were considered during the alignment of solids, which is why the edges of the models do not touch each other directly. Based on the obtained alignments of solids, it is possible to determine how to make cuts in the stone and how to secure it in the holders of saws and grinters. The use of 3D scanning technology and vector graphics provided information for each of the stones about the material losses that could occur during processing. A computational method based on Boolean algebra was used for this purpose. By performing mathematical operations based on volume differences, a comparison of material losses was obtained--Tables 2-4. In each table, Solid No. 6 represented the most favourable alignment model of the diamond model regarding the amber stone. Figure 11: Spatial views in the process of aligning solids (3). Figure 10: Spatial views in the process of aligning solids (2). Prism number 6, included in each table, represents the most favourable matching model of the dodecahedron regarding the amber stone. This method is implemented at Golden Amber, the world's largest supplier of amber raw materials located near Krolewiec/Konigsberg. The company is involved in both amber extraction and processing. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Gem Model**} & \multicolumn{2}{c}{**Amber No. 1**} \\ \hline
**Number of the** & \multirow{2}{*}{**Scale [\%]**} & \multirow{2}{*}{**Volume [mm\({}^{3}\)]**} & **Amber Volume** & **Material Waste** \\
**Solid** & & & **[mm\({}^{3}\)]** & **Obtained** \\ \hline Solid 1 & 100 & 11,984 & & — \\ Solid 2 & 80 & 9587.2 & & — \\ Solid 3 & 60 & 7190.4 & & 6568.6 \\ Solid 4 & 40 & 4793.6 & & 8965.4 \\ Solid 5 & 20 & 2396.8 & & 11,362.2 \\ Solid 6 & 75 & 8988 & & 4771 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of results regarding material losses related to the utilisation of Amber No. 1. Figure 12: View of the final alignment of solids.