TITLE: StyroStone: A protocol for scanning and extracting  three-dimensional meshes of stone artefacts  using Micro-CT scanners
AUTHORS: Dominik  Göldner, Fotios Alexandros Karakostis, Armando  Falcucci

[DESCRIPTION]
This protocol presents the first detailed step-by-step pipeline for the 3D scanning and post processing of large batches of lithic artefacts using a micro-computed tomography (micro-CT) scanner (i.e., a Phoenix v-tome-x S model by General Electronics MCC, Boston MA) and an Artec Space Spider scanner (Artec Inc., Luxembourg). This protocol was used to scan more than 700 lithic artefacts from the Protoaurignacian layers at Fumane Cave in north-eastern Italy (https://doi.org/10.5281/zenodo.6362150).

For this study several costly scanners and proprietary software packages were employed. Although it is not easy to find a low-budget alternative for the scanners, it is possible to use free and open-source software programs, such as 3D-Slicer (https://www.slicer.org/) or MorphoDig (https://morphomuseum.com/morphodig), to process CT data as well as MeshLab (Cignoni et al. 2008) to interact with the 3D models in general. However, if alternative software is used, the steps and their order described in this protocol might diverge significantly.

A cost-effective alternative to create 3D models is digital photogrammetry using commercial cameras and freely available software like Meshroom (https://alicevision.org). Although photogrammetry is an affordable technique to create accurate 3D models of objects, this method might not be useful when scanning large batches of artefacts, as it will require a lot of computation time and processing capacity. Likewise, it could be difficult to generate accurate 3D models of very small and/or detailed tool shapes using 3D surface scanners because stone tools are often much smaller than the recommended minimum field of view. Similarly, the resolution of conventional medical CT scanners might not be sufficient to capture minor details of stone tools, such as the outline or dorsal scars.

This protocol aims at providing the first detailed procedure dedicated to the scanning of small lithic implements for further three-dimensional analysis. Note that some of the steps must be repeated at different working stages throughout this protocol. In cases where a task must be done in the exact same way as described in a previous step, a reference to that step is provided. When slight changes were made, the step was modified and reported entirely. This protocol contains a few red and green colours (e.g., arrows or within-program colours) which might be perceived differently by people with dyschromatopsia. However, the display of these colours has been kept to a minimum.

We recommend the reader to go over the entire protocol carefully, even if only some specific parts are required. A few points are in fact interdependent, and some of them must be applied simultaneously.

Content:
Part 1 – Styrofoam preparation
Part 2 – Micro-CT scanning
Part 3 – 3D model extraction of CT scanned stone artifacts using Avizo
Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
Part 5 – Cropping Face A to separate the lines in Artec Studio
Part 6 – Cropping each stone artefact from the lines in Artec Studio
Part 7 – Virtually control measurements in MeshLab
Part 8 – Artec scanning of larger artifacts
Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph

Three-dimensional example (in ply format) of the effectivity of the StyroStone Protocol:
You can download an example of one Styrofoam line in 3D obtained using our protocol to appreciate the result that can be achieved. We have selected a line where objects are characterized by different metric and morphological attributes. Notice the retouching well visible in the last five smaller artifacts (counting from the left when artifact are oriented with the dorsal face in front of the observer and the butt down), as well as the platforms and bulbs of all artifacts. The rest of the 3D meshes available on Zenodo (https://doi.org/10.5281/zenodo.6362150).
  

[GUIDELINES]
Sections often start with a short preface or introduction including useful background information, notes, or tips inserted in the first step right before the actually step. 

Occasionally, notes and technical warnings, which are both indicated as such, are included in steps where necessary or useful.

Program options or commands are indicated with single quotes (e.g., 'XYZ').  

Whenever referred to another step within a step, the reference step is highlighted in bold. 

References 
Adams, D., Collyer, M., Kaliontzopoulou, A., Baken, E., 2021. Geomorph: Software for geometric morphometric analyses. R package version 4.0. https://cran.r-project.org/package=geomorph

Archer, W., Djakovic, I., Brenet, M., et al., 2021. Quantifying differences in hominin flaking technologies with 3D shape analysis. Journal Of Human Evolution 150, 102912

Artec Studio Professional 13. User´s Guide / Manual. http://docs.artec-group.com/as/13/en
Cignoni, P., Callieri, M., Corsini, M., Dellepiane, M., Ganovelli, F., Ranzuglia, G., 2008. MeshLab: an Open-Source Mesh Processing Tool. Sixth Eurographics Italian Chapter Conference, 129-136

R Core Team (2020). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/

Thermo Scientific™ Avizo™ Software 9 User’s Guide, Berlin. https://assets.thermofisher.com/TFS-Assets/MSD/Product-Guides/user-guide-avizo-software.pdf

[STEPS]
SECTION: Part 1 - Styrofoam preparation
1. Note: Depending on the number of lithics that need to be scanned, this section might take several hours.

Select a blank Styrofoam body (or similar material) to hold the artefacts. It should be thick enough to carve holes on both sides (Face A and Face B).
SECTION: Part 1 - Styrofoam preparation
2. Identify the scanning size limitations of the micro-CT scanner. 
SECTION: Part 1 - Styrofoam preparation
3. Cut the Styrofoam body into a rectangle according to the dimensions determined in Step 2. Our dimensions: 25 cm (height) x 22 cm (width) x 5 cm (thickness). 
SECTION: Part 1 - Styrofoam preparation
3.1. To increase the stability, you might add an additional Styrofoam support as base of ca. 2 cm height and a width of a few cm wider than the area of contact between the two parts (our total Styrofoam body height was 27 cm). 
SECTION: Part 1 - Styrofoam preparation
3.2. Glue the two Styrofoam pieces together with Polyvinyl acetate (white glue).

 

SECTION: Part 1 - Styrofoam preparation
4. Draw guiding or separation lines with a dark marker on both sides (Face A and B) of the Styrofoam body depending on the size and number of artefacts that need to be scanned – these will determine the rows or lines in which the artefacts will be placed one after another.

The row separation will help to keep the artefacts in the same orientation and will simplify the subsequent 3D model extraction after the CT-scanning process. 
SECTION: Part 1 - Styrofoam preparation
5. Draw a mark (e.g., a dot or “A”) on the first side of the Styrofoam (Face A), which will later facilitate the correct identification of the artefacts.
SECTION: Part 1 - Styrofoam preparation
6. Carve holes along rows into the Styrofoam with a box cutter that are roughly the same dimensions of the artefacts. They should be secure enough to ensure a stable positioning and protect the artefacts from moving during the CT-scanning process. 
SECTION: Part 1 - Styrofoam preparation
6.1. Insert the artefact directly into its hole and immediately document its position in the Styrofoam as described in Step 6.2 (Fig. 1).

On Face A, place the first artefact on the left most position of the first row and continue in this line towards the right until the line is fully occupied. Then continue with the second row below, again starting at the left side until Face A is completed. Continue with Face B in the same way. 

Insert lithics following the best-suited criteria depending on how the lithic assemblages are curated (e.g., stratigraphic units, raw materials, ID numbers) or according to the size variation of the artefacts if necessary.

Always use the same orientation of the artefacts, i.e., dorsal face facing upwards and proximal side at the bottom. By placing the longest axis of the specimen vertically, the object thickness between the source and the detector remains limited during the scanning process, requiring less x-ray penetration power and thus reducing energy costs. Moreover, during the later post-processing step, such an orientation will enable easier identification and virtual separation among 3D scans of lithics when compared with the reference list of artefacts (Step 6.2) and reference photographs of the Styrofoam body (Step 7.1 and 7.2).

In our case, we scanned ca. 700 lithics with the CT-scanner using 4 Styrofoam bodies each with two faces (A and B) for a total of 8 faces. Each face consisted of ca. 4 to 8 lines and each line contained ca. 10 to 20 artefacts (total of ca. 60 to 120 artefacts per face).

   

SECTION: Part 1 - Styrofoam preparation
6.2. Document the exact position of each artefact in a spreadsheet (e.g., MS Excel) directly after it is inserted into its Styrofoam hole.

Clearly indicate the Styrofoam side, row, and at which numeric position the artefacts are located. For simplicity reasons you might use a coded identification key.

Example: An artefact with the location code S1-FA-L2.5 would be inserted into first Styrofoam body (S1; only in cases where several bodies must be used to scan large amounts of lithics) Face A (FA, first Styrofoam side) in the second row from the top to the bottom (L2) and at the fifth position from the left to the right (.5) in this row.

Keeping track of the positions is extremely important and will not only ensure the fast and correct labelling of the right artefact ID with the 3D models, but also ensure the artefacts are safely returned to their find bags. Therefore, you might use a handwritten list as backup. 
SECTION: Part 1 - Styrofoam preparation
7. Take reference pictures.
SECTION: Part 1 - Styrofoam preparation
7.1. After Face A and B are filled, take reference pictures of both faces.
SECTION: Part 1 - Styrofoam preparation
7.2. Take a picture of the first artefact of the first row of each face. This will serve as a reference to orient the 3D model of the entire face, making the later identification of the artefacts’ order much easier.
SECTION: Part 1 - Styrofoam preparation
8. Cover the Styrofoam faces with Styrofoam slabs.
SECTION: Part 1 - Styrofoam preparation
8.1. Cover both Faces A and B with a thin Styrofoam slab (ca. 1 cm thickness) of the same dimensions as the main Styrofoam body (Step 3).
SECTION: Part 1 - Styrofoam preparation
8.2. Tightly secure the two Styrofoam slabs and main Styrofoam body with plastic rubber bands (Fig. 2). Do not glue them together, as it will be difficult to disassemble when removing the lithics after scanning.

  

 

SECTION: Part 1 - Styrofoam preparation
9. Repeat Step 1 to Step 8.2 if more Styrofoam bodies are needed (S1, S2, etc.; see Step 6.2 for labelling).
SECTION: Part 1 - Styrofoam preparation
9.1. Label each Styrofoam body with a number to identify them afterwards (Fig. 3).

   

SECTION: Part 2 - Micro-CT scanning
10. Note: CT-scanning is usually performed by a certified and trained technician using the scanning parameters specified below and depending on the inherent nature of the different raw materials. The following steps are a summary of the scanning process performed for our case study, which relied on the scanning of fine-grained chert bladelets with thicknesses between 0.5 mm to 6.0 mm (mean: 2.4 mm).

In our study, each scan took approximately 2:20 hours and we scanned up to 220 bladelets per scan (these bladelets had an average size of 28 x 8 x 2.4 mm).

Place the Styrofoam body on the turning base of the CT-scanner (Fig. 4).

  


SECTION: Part 2 - Micro-CT scanning
11. Secure it with a strong double-sided tape on the base. 
SECTION: Part 2 - Micro-CT scanning
12. The turning base should be positioned as far as possible from the source to increase the field of view and, therefore, the number of lithics that can be scanned at one time. Note that with greater distance from the source, the resolution decreases. 

SECTION: Part 2 - Micro-CT scanning
13. Set up the machine according to the best scanning parameters – usually done by the scanning technician.

For scanning multiple specimens at the same time, it is advisable to use the “multiscans” option, which enables the device to scan longer targets within the same scanning session. In particular, using the scanner’s associated computer device and software (e.g., Phoenix Datos-X software; General Electronics MCC), the scanning technician virtually separates the target into different layers (by Styrofoam height) to be scanned individually (per layer/scan), which are then automatically merged before model reconstruction. It must be highlighted that the use of this option might produce visual artefacts in the resulting 3D models, appearing as lines at the borders in between the layered scans (i.e., “merging lines”). To ensure that these lines will not affect stone tool morphology, the technician should make sure that the selected upper and lower borderlines of each layer/scan do not intersect any stone tools.

The resolution used across our scans was ca. 140 microns. Resolution largely depends on the distance between the source and the target/object. Even though the utilized micro-CT scanner is technically capable of producing models with much greater resolution, our experiments showed that 140 microns was a good balance, allowing us to scan a large number of artefacts at once, while avoiding distinguishable inaccuracies in the resulting 3D surface form (size and shape) of the blades and bladelets.
SECTION: Part 2 - Micro-CT scanning
14. Start scanning process. 
SECTION: Part 2 - Micro-CT scanning
15. After the scanning process is completed, save the scans onto a hard disk. Make sure to save the scanning metadata (e.g., as .pcr file), including all scanning parameters, which are required to open and scale the CT scans (e.g., in Avizo). Important scanning parameters to successfully load the CT data into Avizo Lite are the resolution (Voxel size), volume dimensions (x, y, z), and image data type (e.g., 16 bit).
SECTION: Part 2 - Micro-CT scanning
16. Visualize the overall scanning result to check for obvious errors. This can be done by reconstructing the CT data and exporting the file as an image stack, e.g., as .tiff files or .vol files, which can be opened in Avizo Lite. Reconstruction of the CT data can be performed, visualized, and exported using software like Phoenix Datos-X. 
SECTION: Part 2 - Micro-CT scanning
17. Take the scanned Styrofoam body from the CT scanner.
SECTION: Part 2 - Micro-CT scanning
18. Dismantle the Styrofoam body by taking off the plastic rubber strings and the covering plates. 
SECTION: Part 2 - Micro-CT scanning
19. Remove the artefacts one by one from the Styrofoam and put them back into their respective find bags.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20. Note: For our project the preparation and separation of the faces took around 2 hours per Styrofoam body. The subsequent extraction of each lithic described in the next chapter (Part/Section 4) only took around one minute per artefact.
  

Open CT scan in Avizo Lite.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.1. Open Avizo and load CT scan (.vol file).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.2. In ‘File Format Selection’ choose ‘Raw Data’ and press ‘Okay’ (Fig. 6).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.3. In ‘Out-of-Core Data’ choose ‘Read complete volume into memory’ and press ‘Okay’ (Fig. 7).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.4. Indicate raw data parameters in ‘Raw Data Parameters’ window (Fig. 8).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.5. Set ‘Data type’ according to scanner settings (usually ‘16-bit unsigned’) (blue arrow in Fig. 8), leave the rest as the pre-set values.

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.6. Open CT meta-data file (e.g., pcr in this study). It should open automatically in notepad (Fig. 9).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.7. To enter the x-, y-, and z-dimensions in the ‘Raw Data parameters’ window (violet arrow in Fig. 8) search for ‘ROI_SizeX=NUMBER’, ‘ROI_SizeY=NUMBER’ and ‘ROI_SizeZ=NUMBER’ respectively (violet arrow in Fig. 9).

Note: you should usually aim for the parameters ‘Volume_Size[X, Y, or Z]’ (blue arrow in Fig. 9), especially when the ROI (Region of Interest) was specified before the scanning process. In our case ROI was not specified and is therefore identical to the volume size. If ROI is specified by the technician, the ROI parameter reported in the metadata file will only show a part of the image.

Caution: ‘Header’ value (pink arrow in Fig. 8) in ‘Raw Data Parameters’ window will change to 0 if all dimensions are entered correctly.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.8. To enter the voxel size value into ‘Raw Data parameters’ window (yellow arrow in Fig. 8), search for ‘VoxelSizeRec=NUMBER’ (yellow arrow in Fig. 9).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.9. Leave all other parameters in ‘Raw Data Parameters’ window as the pre-sets and press ‘Okay’.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.10. Indicate unit in ‘Units Editor’ window (Fig. 10) according to indicated voxel size unit in pcr CT-scan metadata file (‘VoxelSizeRec=NUMBER’, yellow arrow in Fig. 9) and press ‘Okay’.

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
20.11. Now, Avizo should load and open the vol file (Fig. 11).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21. Generate isosurface (also see manual: https://assets.thermofisher.com/TFS-Assets/MSD/Product-Guides/user-guide-avizo-software.pdf).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.1. Click on vol file label and then on the ‘Isosurface’ button that appears in the options bar above to generate an isosurface of the scan. Alternatively, if it does not appear, click on the arrow sign at the right most position of the vol file label and enter ‘Isosurface’ in the search bar. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.2. Click on the newly generated ‘Isosurface’ label (Fig. 12) and choose a ‘Threshold’ value (yellow arrow in Fig. 12) that separates the artefacts from the surrounding air, Styrofoam etc.

Enable and use ‘Down Sample’ (pink arrow in Fig. 12) to run a fast isosurface test extraction to check whether the chosen ‘Threshold’ value works well. 

Time can be saved by finding a good threshold, as this lessens the need for cleaning and outlier removal. Note that a preview mode is not available, so it is not possible to judge whether the chosen ‘Threshold’ value works well overall. Therefore, it might be necessary to test multiple values before a good separation can be achieved (Step 21.5). It might be useful to note down the values that have already been tested and to narrow down a suitable Threshold value range.

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.3. Press ‘Apply’ and wait until the process completed. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.4. When completed, inspect the resulting isosurface model (Fig. 13 and 14) and check for ‘unusual’ or ‘unnatural’ surface inconstancies, ‘noise’, and scanning artefacts.

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.5. If the chosen ‘Threshold’ value does not work well, repeat Step 21.2 and 21.3 until a good separation is be achieved. If the chosen threshold works well, continue with Step 21.6.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.6. If a suitable threshold value was found, repeat Step 21.2 and 21.3 using the indicated threshold value (e.g., by copy and paste) but this time with ‘Down Sample’ disabled. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.7. When completed, again inspect the resulting isosurface model (Fig. 13 and 14) and check surface inconstancies (see Step 21.5).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
21.8. If the chosen ‘Threshold’ value does not work well, repeat Step 21.2) and 21.3 until a good separation is achieved. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22. Remove remaining materials.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.1. Select the ‘Eye’ sign in the top menu bar above the 3D viewing panel (grey arrow in Fig. 15) to switch to orthographic view (‘Eye’ sign with parallel sight lines).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.2. Select the vol file label (yellow arrow in Fig. 15). 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.3. Rotate the 3D model into a proper position (e.g., as shown in Fig. 15) that allows for easier removal of the unnecessary outlying material. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.4. Select the ‘Cursor’ sign in the menu bar above the 3D viewing panel (blue arrow in Fig. 15). 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.5. Select the first ‘Tool’ sign (Cropping tool) in the options bar (pink arrow in Fig. 15).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.6. Use the left mouse button and cursor to narrow the bounding box (brown arrows in Fig. 15). If possible, leave only the lithic artefacts within the bounding box (Fig. 16). Any remaining materials can still be excluded later if necessary. Switch between ‘Cursor’ and ‘Hand’ (i.e., dragging) mode and change the position of the 3D model to adjust bounding box in all dimensions to crop out as much of the outlying material as possible.

   

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
22.7. Apply changes to delete excluded materials with ‘Ok’ in cropping window (green arrow in Fig. 15). 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
23. Generate isosurface again for cropped scan.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
23.1. Click on vol file label and then on the ‘Isosurface’ button (blue arrow in Fig. 17) that appears over the options bar to generate an isosurface of the scan (like Step 21.1).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
23.2. Click on the newly generated ‘Ie,sosurface’ label (yellow arrow in Fig. 18). Disable ‘Down Sample’ and insert the ‘Threshold’ value identified to be sufficient earlier in Step 21.2 or Step 21.5 / 21.6. 

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
23.3. Click ‘Apply’ (pink arrow in fig. Fig. 18) and wait until the process has completed. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
24. Extract surface from cropped isosurface.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
24.1. Click on the newly generated isosurface (here ‘Isosurface 2’, blue arrow in Fig. 19).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
24.2. Click ‘Extract Surface’ in the options bar above (yellow arrow in Fig. 19).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
24.3. Select the newly created label called ‘Extract Surface’ (orange arrow in Fig. 20).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
24.4. Leave all parameters in the ‘Extract Surface’ menu as is and click ‘Apply’ to generate extracted surface (pink arrow in Fig. 20).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
24.5. A new label called ‘ExtractedSurface’ will appear (blue arrow in Fig. 21).

  

SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25. Save extracted surface model.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25.1. Click on the newly generated‘ExtractedSurface’ label.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25.2. Go to ‘File’ in the menu bar and click ‘Export data as’.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25.3. Navigate to the target folder where you want to save the model. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25.4. Name model. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25.5. Choose file format (e.g., .ply, .stl, .obj).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
25.6. Click on ‘Save’ to save the model.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26. Save the Avizo project. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.1. Go to ‘File’ in the menu bar and click ‘Save Project’. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.2. Select appropriate option in the ‘Save Project Policy’ window (here: ‘Minimize project size’).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.3. Click ‘Okay’ to confirm selection. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.4. Navigate to the target folder to save the Avizo project. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.5. Name project.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.6. Do not change pre-selected file type (.hx).
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.7. Click ‘Save’ to save the Avizo project. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.8. A new window might open in Avzio asking to save labels from the project that are necessary to reconstruct the saved Avizo project. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.9. The target folder should open automatically, if not navigate to it.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.10. Leave label names as is.
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.11. Click ‘Save’ to save the labels. 
SECTION: Part 3 – 3D model extraction of CT scanned stone artefacts using Avizo
26.12. Close Avizo Lite.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27. Load 3D model into Artec (Fig. 22).

  
 
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.1. Copy the extracted model file 2 times to get one file for Face A, one for Face B, and one backup file just in case. Name them accordingly.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.2. Open Artec Studio.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.3. Click on ‘File’ in the top menu bar and then on Import\scans, meshes or point clouds. Alternatively drag and drop the 3D model file into Artec Studios’ 3D View panel directly from its storage location. 
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.4. Navigate to target folder where the extracted 3D model is stored.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.5. Select the first 3D model file for the creation of Face A.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.6. Click ‘Open’ to load the 3D model into Artec Studio.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.7. Press ‘NUM 5’ to switch to orthographic view.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
27.8. Inspect loaded model in Artec Studio (Fig. 23).

  

SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28. Deletion of Face B.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28.1. Rotate the model with the left mouse curser in the 3D View Panel so that both faces are parallel to each other like shown in Fig. 24.

  

SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28.2. Click on ‘Editor’ in the left Tool Menu Bar.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28.3. Click on ‘Eraser’.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28.4. Select ‘Lasso selection’ in the opened Eraser Panel. 
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28.5. Press and hold Ctrl while pressing and moving the left cursor over the material from Face B. Selected areas will be highlighted in red (Fig. 24).
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
28.6. Click ‘Erase’ in the Eraser Panel or press the ‘Delete’ key to delete the selected area (Fig. 25).

  

SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
29. Delete outlying materials.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
29.1. If closed, reopen the ‘Eraser’ menu, and reselect the ‘Lasso’ tool (see Step 28.2 to 28.4).
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
29.2. To remove the outlying materials, press and hold Ctrl while pressing and dragging the left cursor over the materials. Selected areas will be marked in red (Fig. 26).

   

SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
29.3. If it is not possible to select all outlying materials at once, repeat Step 29.2 until only the stone artefacts remain. It might help to rotate the entire scan to get a better viewpoint. 
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30. Save the isolated and cleaned Face (Fig. 27).

  

SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30.1. Go to ‘File’ in the menu bar and click on ‘Export\Meshes’.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30.2. Navigate to the target folder in which to save the model. 
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30.3. Name model (e.g., “Styro 1_Face A_Cropped and Cleaned”).
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30.4. Choose file format (e.g., .ply, .stl, .obj, or .wrl).
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30.5. Click on ‘Save’ to save the model.
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
30.6. In the storage folder duplicate Face A file by copying it to create a backup file. Name it accordingly (e.g., “Styro 1_Face A_Cropped and Cleaned_Backup”).
SECTION: Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio
31. Repeat the workflow for Face B with the copied version of the extracted Avizo file from Step 27.1.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
32. Create a folder where the individual lines are stored and name it accordingly. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
33. Open the cropped and cleaned model of Face A in Artec Studio. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34. Crop the lines to separate them.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.1. Rotate the model with the left mouse curser in the 3D View Panel as shown in Fig. 27. Remember to position the scan so that their order corresponds to their actual order, i.e., the first artefact in the model must be the first on in the list, so it is placed on the upper left. Also remember to look at the scan from the correct side. The scan can also be oriented using the reference pictures. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.2. Click on ‘Editor’ in the left Tool Menu Bar.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.3. Click on ‘Eraser’. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.4. Select ‘Lasso selection’ in the Eraser Panel. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.5. Press and hold Ctrl while outlining all rows except the one that you want to separate. Selected areas will be marked in red (Fig. 28).

  

SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.6. Click ‘Erase’ in the Eraser Panel or press the ‘Delete’ key to delete the selected rows.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
34.7. Alternatively, you can select the line that you want to separate and then inverse the selection with the ‘Inverse’ button in the Eraser Panel. To delete the selection, apply Step 34.6. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35. Save the separated line (Fig. 29).

  

SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35.1. Click on ‘File’ in the top menu bar.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35.2. Click on ‘Export as’. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35.3. Navigate to the target folder.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35.4. Name the cropped line accordingly (e.g., “Styro 1_Line 1”).
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35.5. Select the file format (e.g., .ply, .stl. etc.).
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
35.6. Press ‘Okay’ to export the cropped line.

Important: Do not save and close the entire project. All deleted lines will be lost otherwise! See next step.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
36. Recall the deleted lines to continue separating the next line.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
36.1. Press Ctrl and Z to undo the deletion or click on ‘Edit’ in the top menu bar and press on ‘Undo’. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
37. Separate the next line. 
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
37.1. Apply Steps 34.2 to 34.6 for the next line.
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
37.2. Apply Steps 35.1 to 35.6 to save the newly separated line. Remember to name it accordingly (e.g., “Styro 1_Line 2” for the second line and so on).
SECTION: Part 5 – Cropping Face A to separate the lines in Artec Studio
38. Repeat all steps for each line individually.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
39. Create a backup copy of each of the separated lines and name them accordingly.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
40. Create folders for each line and name it accordingly. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
41. Move the separated lines into their respective folder.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
42. Open the first line with Artec Studio. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43. Crop the stone artefacts to separate them.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.1. Rotate the line model with the left mouse curser in the 3D View Panel as shown in Fig. 30. Remember to position the scan so that the artefacts in the model correspond to their actual order, i.e., the first artefact in the model must be the first on in the list, so it is positioned in the upper left. Also remember to look at the scan from the correct side. This can be done by orienting the scan using the reference pictures.

  

SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.2. Click on ‘Editor’ in the left Tool Menu Bar.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.3. Click on ‘Eraser’. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.4. Select ‘Lasso selection’ in the Eraser Panel. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.5. Press and hold Ctrl while selecting all artefacts but the one that you want to separate. Selected artefacts will be highlighted red (Fig. 31).

  

SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.6. Click ‘Erase’ in the Eraser Panel or press the ‘Delete’ key to delete the selected artefacts.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
43.7. Alternatively, you can also select only the artefact that you want to separate and then inverse the selection with the ‘Inverse’ button in the Eraser Panel. To delete the selection, apply Step 43.6. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44. Export and save the separated artefact (Fig. 32).

  

 
 

SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.1. Click on ‘File’ in the top menu bar.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.2. Click on ‘Export as’.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.3. Navigate to the target folder.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.4. Name the cropped artefact with the actual artefact ID.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.5. It might also be useful to add information on the exact location within the Styrofoam scan to trace potential errors. A possible location ID which can be added either before or after the actual artefact ID in the file name could look like this: 

S1-FA-L1.1_10401

S1 stands for the first Styrofoam scan, FA stands for Face A, L1.1 stands for the first line – first artefact. The last number 10401 represents the artefact ID. It might also be useful to include this information in the artefact database. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.6. Select the file format (e.g., .ply, .stl. etc.). Remember to also export the model as a .wrl file, as AGMT-3D only can import this file format. If the R package geomorph will be used subsequentially, the models must be saved as non-binary ply files (see below). 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
44.7. Press ‘Okay’ to export the cropped artefact.

Note: Do not save and close the entire project. All deleted lines will be lost otherwise! See next step.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
45. Recall the deleted artefacts to continue separating the next one.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
45.1. Press Ctrl + Z to undo the deletion or click on ‘Edit’ in the top menu bar. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
46. Separate the next artefact. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
46.1. Apply Steps 43.2 to 43.6 for the next artefact.
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
46.2. Apply Steps 44.1 to 44.7 to export and save the newly separated artefacts. Remember to name it accordingly (see Step 44.5).
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
47. Repeat all steps for each artefact individually. 
SECTION: Part 6 – Cropping each stone artefact from the lines in Artec Studio
48. Repeat these steps for all lines.
SECTION: Part 7 – Virtually control measurements in MeshLab
49. Note: It might be useful to take control measurements for time to time, e.g., of the first and last artefact in a line and a few random artefacts elsewhere. This helps to check whether the line is exactly positioned and whether any artefacts were accidently skipped.
 
If all artefacts are measured, errors in the database could also be cross-checked. However, with larger sample sizes, this may take a lot of time. Linear measurements (e.g., maximum length of the artefact) can easily be taken in MeshLab (Cignoni et al. 2008) then compared with physically measured variables in the main database. For any subsequent intra- or interobserver error and methodological evaluations, it might be useful to store the virtual control measurements in an extra column of the main database. To save time, this task can easily be combined with the export of the models to non-binary ply. files if necessary for subsequent analysis in the R package geomorph  (see below).

Open MeshLab.
SECTION: Part 7 – Virtually control measurements in MeshLab
50. To load the first artefact into MeshLab, drag the model file and drop it into the 3D View Panel of MeshLab. Alternatively, click on ‘File’ in the top menu bar and choose ‘Import Mesh’, then navigate to the target folder and open the desired model by pressing ‘Open’ (Fig. 33).

  

SECTION: Part 7 – Virtually control measurements in MeshLab
51. Press ‘5’ on the keyboard to switch to orthographic view.
SECTION: Part 7 – Virtually control measurements in MeshLab
52. Click on the ‘Point to Point Measure Tool’ in the Tool bar above the 3D View Panel (blue arrow in Fig. 33). In this mode, the tracking ball will vanish, making it impossible to rotate the model (but see note within Step 54). 
SECTION: Part 7 – Virtually control measurements in MeshLab
53. Click with the left mouse curser on the starting point of the measurement.
SECTION: Part 7 – Virtually control measurements in MeshLab
54. Click with the left mouse curser on the end point of the measurement to finish the measurement.

Note: If it is necessary to rotate the model, place the first point (Step 53) and then press ‘Esc’ on the keyboard to temporally leave the measuring tool. When the tool is disabled, the tracking ball will reappear. Rotate the model accordingly and then press ‘Esc’ to return to the measuring mode. 
SECTION: Part 7 – Virtually control measurements in MeshLab
55. After the measurement is taken, the model can be rotated to check the placements and evaluate the measurement. Redo if necessary, by double clicking on the ‘Measuring Tool’ in the Tool bar menu and repeating Steps 52 to 54.
SECTION: Part 7 – Virtually control measurements in MeshLab
56. The measurement will appear beside the end point of the measurement, as well as in the ‘Point to Point Measure’ panel in the upper left corner of the 3D View Panel and in the lower right Log Panel (pink arrows in Fig. 33). 
SECTION: Part 7 – Virtually control measurements in MeshLab
57. Copy the measurement value to the main database and/or compare with previous measurements to control for error. 
SECTION: Part 8 – Artec scanning of larger artefacts
58. General tips for Artec scanning:

The lighting in the room should be uniform, cold and diffuse;
Try to reduce areas of shading during the scanning process; 
Use a scanning speed of 8 fps (frames per second) and a depth of 170. Both can be adjusted in the Scan menu in Artec Studio;
For dark objects set a higher brightness. 

Note: Calculation of surface texture colour is not necessary for most analyses. In order to save time and computation capacity, this step is not included here. 


Set up the scanner and workspace.
SECTION: Part 8 – Artec scanning of larger artefacts
59. Boot the scanning computer.
SECTION: Part 8 – Artec scanning of larger artefacts
60. Set up the Calibration equipment according to the Artec manual (http://docs.artec-group.com/as/13/en).
SECTION: Part 8 – Artec scanning of larger artefacts
61. Open the Artec Studio software.
SECTION: Part 8 – Artec scanning of larger artefacts
62. Calibrate the Artec scanner according to the official instructions of the Artec manual (http://docs.artec-group.com/as/13/en).
SECTION: Part 8 – Artec scanning of larger artefacts
63. Put the calibration equipment away.
SECTION: Part 8 – Artec scanning of larger artefacts
64. Set up the turntable. We recommend using a white turntable or cover a turntable with white cardboard. As suggested by Archer et al. (2021), red and blue circles should be randomly marked on the turntable’s surface to enhance tracking during scanning (Fig. 34).

  

SECTION: Part 8 – Artec scanning of larger artefacts
65. Place the artefact on the turntable.

Use modeling clay to secure the lithic vertically on the table so that it will not move during the scanning process. 
SECTION: Part 8 – Artec scanning of larger artefacts
66. Start the pre-scanning process by pressing the button on the back of the Artec handle upwards. 
SECTION: Part 8 – Artec scanning of larger artefacts
67. Find the optimal distance between the scanner and the artefact, indicated by the range on the left side of the scanning computer screen and the color of the objects in view. Green means optimal distance, blue too far away, and red to close. 
SECTION: Part 8 – Artec scanning of larger artefacts
68. Press the button on the back of the Artec handle upwards again to start the scanning process. 
SECTION: Part 8 – Artec scanning of larger artefacts
69. Hold the scanner in one hand while slowly but steadily spinning the turntable with the other hand. Keep your eyes on the scanning computer monitor to watch the scanning progress, navigate the scanning directions and to keep a constant scanning speed. 
SECTION: Part 8 – Artec scanning of larger artefacts
70. When the scan is completed stop the scanning process by pressing the button on the back of the Artec handle downwards. 
SECTION: Part 8 – Artec scanning of larger artefacts
70.1. Artec Studio will automatically run the ‘Fine registration’. 
SECTION: Part 8 – Artec scanning of larger artefacts
71. Turn the artefact upside down on the table using the modeling clay (Step 65) to capture the side that could not be scanned in the first round. Sometimes objects need to be scanned from more than two sides to capture all areas. 
SECTION: Part 8 – Artec scanning of larger artefacts
72. Repeat Step 66 to Step 70.1 to scan the second side. 
SECTION: Part 8 – Artec scanning of larger artefacts
73. Removing the base and outlying material.
SECTION: Part 8 – Artec scanning of larger artefacts
73.1. Open the ‘Editor’ menu in Artec Studio. 
SECTION: Part 8 – Artec scanning of larger artefacts
73.2. Open the ‘Eraser’ tool. 
SECTION: Part 8 – Artec scanning of larger artefacts
73.3. Select the ‘Lasso selection’ tool.
SECTION: Part 8 – Artec scanning of larger artefacts
73.4. While pressing the left mouse button, move the scanned artefact model into a position where the base can easily be removed without deleting to much of the artefact itself, i.e., by placing the model so that the flat base part is horizontally aligned and only appears as a thin line on the screen display. 
SECTION: Part 8 – Artec scanning of larger artefacts
73.5. Press and hold Ctrl + left mouse button to apply the lasso tool, then drag it around the base part to select it. Selected areas will be marked in red.
SECTION: Part 8 – Artec scanning of larger artefacts
73.6. Press ‘Delete’ on the keyboard or ‘Erase’ in ‘Eraser’ menu to delete the selected base. 
SECTION: Part 8 – Artec scanning of larger artefacts
73.7. Repeat Step 73.4 to Step 73.6 for the second scan. Disable the first scan and enable the second scan in the model scan menu on the right side. If you have more than two scans, repeat the base removal steps for all of them. 
SECTION: Part 8 – Artec scanning of larger artefacts
73.8. Close the ‘Eraser tool menu. This will also close the ‘Editor’ menu.
SECTION: Part 8 – Artec scanning of larger artefacts
74. Align the sub-scans.
SECTION: Part 8 – Artec scanning of larger artefacts
74.1. Open the ‘Align’ menu.
SECTION: Part 8 – Artec scanning of larger artefacts
74.2. Press ‘Auto-alignment’. 

In most cases automatic alignment should work successfully. However, when the program is not able to detect multiple matching points itself, this must be done manually. If the program misaligned two or more sub-scans, cancel the result. 

To manually align sub-scans, use the options to place matching pairs between each scan. If there are more than two sub-scans, align one after the other. With this function three to five pairs of homologous points must be placed on both sub-scans. Choose points that are characteristic and can easily be identified on both sub-scans. The placement does not have to be extremely perfect. The software will detect the right point itself.
SECTION: Part 8 – Artec scanning of larger artefacts
74.3. Press ‘Apply’ to complete the process and to leave the ‘Align’ menu.
SECTION: Part 8 – Artec scanning of larger artefacts
75. Finish the model.
SECTION: Part 8 – Artec scanning of larger artefacts
75.1. Open the ‘Tools’ menu.
SECTION: Part 8 – Artec scanning of larger artefacts
75.2. Apply ‘Global registration’.
(Use default settings: Geometry and texture; Key frame ratio: 0.1; Focus on geometry disabled; Search features within, mm: 50).
SECTION: Part 8 – Artec scanning of larger artefacts
75.3. Apply ‘Sharp fusion’. 
(Use default settings: 3D resolution, mm: 1; Fill holes: With radius smaller …; Hole radius (max), mm: 5; Remove targets disabled).
SECTION: Part 8 – Artec scanning of larger artefacts
75.4. Apply ‘Hole filling’.
(use default settings: Hole perimeter (max), mm: 100)
SECTION: Part 8 – Artec scanning of larger artefacts
75.5. Apply ‘Small-object filter’. 
(Use default settings: Remove surfaces: All except largest)
SECTION: Part 8 – Artec scanning of larger artefacts
76. Save the project.
SECTION: Part 8 – Artec scanning of larger artefacts
76.1. Click on ‘File’ in the top menu bar.
SECTION: Part 8 – Artec scanning of larger artefacts
76.2. Click on ‘Save project as …’.
SECTION: Part 8 – Artec scanning of larger artefacts
76.3. Navigate to and select the target folder.
SECTION: Part 8 – Artec scanning of larger artefacts
76.4. Name the project with the actual ID of the artefact.
SECTION: Part 8 – Artec scanning of larger artefacts
76.5. Press ‘Okay’ to finish this step.
SECTION: Part 8 – Artec scanning of larger artefacts
77. Export model as ply file.
SECTION: Part 8 – Artec scanning of larger artefacts
77.1. Click on ‘File’ in the top menu bar.
SECTION: Part 8 – Artec scanning of larger artefacts
77.2. Click on ‘Export’.
SECTION: Part 8 – Artec scanning of larger artefacts
77.3. Click on ‘Meshes’.
SECTION: Part 8 – Artec scanning of larger artefacts
77.4. Select .ply as file format.
SECTION: Part 8 – Artec scanning of larger artefacts
77.5. Save the exported ply mesh following the instructions in Step 76.3 to Step 76.5.
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
78. Note: As the R (R Core Team 2020) package geomorph (Adams et al. 2021) requires non-binary ply models, the program MeshLab (Cignoni et al. 2008) can be used to export and save the separated artefacts in this required format. 

Open MeshLab.
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
79. To load the first artefact into MeshLab, drag the model file and drop it into the 3D View Panel of MeshLab. Alternatively, click on ‘File’ in the top menu bar and choose ‘Import Mesh’, then navigate to the target folder and choose and open the respective model by pressing ‘Open’ (Fig. 35)

  .

SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
80. Press ‘5’ on the keyboard to switch to orthographic view.
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
81. Press Ctrl + Shift + E to export the model or click on File\Export Mesh As…
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
82. Navigate to the target folder.
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
83. Select file format (note: if you change the current file format, it might be necessary to (partially) rename the file).In the ‘Choose Saving Options for ID’ panel, disable ‘Binary encoding’ (Fig. 36).
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
84. Press ‘Open’.
SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
85. In the ‘Choose Saving Options for ID’ panel, disable ‘Binary encoding’ (Fig. 36).

  

SECTION: Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph
86. Press ‘Okay’.