Jun 07, 2024
An experimental approach on dynamic Occlusal Fingerprint Analysis to simulate use-wear development and localisation on stone tools
- Hannah Rausch1,
- Ottmar Kullmer2,
- Joao Marreiros3,
- Lisa Schunk4,
- Walter Gneisinger4,
- Ivan Calandra5
- 1Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany;
- 2Senckenberg Research Institute and Natural History Museum Frankfurt/M., Germany;
- 3TraCEr. MONREPOS, LEIZA;
- 4Institute of Archaeology, Faculty of Historical and Pedagogical Sciences, University of Wroclaw, Poland;
- 5Imaging Platform at LEIZA (IMPALA)
Protocol Citation: Hannah Rausch, Ottmar Kullmer, Joao Marreiros, Lisa Schunk, Walter Gneisinger, Ivan Calandra 2024. An experimental approach on dynamic Occlusal Fingerprint Analysis to simulate use-wear development and localisation on stone tools . protocols.io https://dx.doi.org/10.17504/protocols.io.261ge346dl47/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We used this protocol and it worked.
Created: October 05, 2022
Last Modified: June 07, 2024
Protocol Integer ID: 70878
Abstract
Occlusal Fingerprint Analysis (OFA) was applied to four sets of experimental stone tool samples and contact materials in a pilot study. The goal of the study was to test the applicability of OFA for locating and quantifying areas of use-wear. The variables tool sample morphology and contact material were tested with unilinear cutting strokes.
The study was conducted between October 2022 and May 2023 in the TraCEr laboratory, MONREPOS, Neuwied (LEIZA). All data was collected by Hannah Rausch (Uni Münster) with the exception of the data from sample FLT8-1, which was collected by Lisa Schunk (TraCEr).
Protocol materials
Acetone ≥99.5 %Carl RothCatalog #5025.6
Plurafac LF 901BTC Europe GmbH, Rheinpromenade 1, D-40789 MonheimCatalog #-
Acetone ≥99.5 %Carl RothCatalog #5025.6
Replifix-20 BlueStruers
Replifix-20 YellowStruers
UHU Reparaturmasse Epoxy Kitt BauhausCatalog #Prod.Nr. 22709985
Plurafac LF 901BTC Europe GmbH, Rheinpromenade 1, D-40789 MonheimCatalog #-
Acetone ≥99.5 %Carl RothCatalog #5025.6
Acetone ≥99.5 %Carl RothCatalog #5025.6
Modified bone-like polyurethaneSYNBONE®Catalog #PR0114
AccuTrans AB forensic silicone (polyvinylsiloxane)
Technovit Provil Light regularKulzer GmbHCatalog #66009333
Sample preparation
Sample preparation
1d
1d
Experimental tools
Two blades with a natural sample morphology are knapped for the experiment.
2 blades Baltic flint
Raw material
Baltic flint; Southern Sweden (secondary deposit) with the following coordinates:
Note: This raw material is used for all samples.
Knapped tool samples
The raw material is knapped into blades. Both blades are retouched laterally.
a) Tool sample FLT13-1 (knapped by Olaf Jöris) is retouched with direct impacts from a hard hammer (pebble) and has the following dimensions:
83.4 mm length
27.3 mm width
6.3 mm thickness
b) Tool sample FLT13-12 (knapped by Frank Moseler) is retouched with direct impacts from a hard hammer (pebble) and has the following dimensions:
71.9 mm length
21.5 mm width
8.4 mm thickness
Dorsal side of blade FLT13-1.
Ventral side of blade FLT13-12.
Sample clamps
Sample clamps are prepared for cutting cycles with the SMARTTESTER® (step #9).
UHU Reparaturmasse Epoxy Kitt BauhausCatalog #Prod.Nr. 22709985
a) epoxy paste is cut15 mm
b) mass is kneaded
c) plastic foil is spanned in the clamp
d) the mass is placed in the sample holder from the SMARTTESTER®
e) the blade is added and the screw of the sample holder (SMARTTESTER®) is tightened
Fixing the sample clamp.
f) the holder is left to set 12:00:00
12h
Sample supports
Sample supports are made for holding the knapped samples during documentation. The following silicone components are mixed:
Replifix-20 BlueStruers 20 g
Replifix-20 YellowStruers 20 g
The silicone sample holder is left to set 00:25:00 at 25 °C
Sample holder curing.
25m
Standardised tool samples
Two experimental standard saw-cut tool samples with a 45° edge angle are produced for the experiment.
2x 45 ° flakes Baltic flint
Flakes
a) Tool sample FLT8-1 and its acquired experimental data was adopted from a previous study from Lisa Schunk et al. 2021:
CITATION
Tool sample FLT8-1 has the following dimensions:
24.6 mm length
46.6 mm width
10.8 mm thickness
b) Tool sample FLT8-13 is produced by sawing off the base of sample FLT8-1 with a diamond saw. Then, an edge angle of 45 ° is cut using the diamond saw.
Schematic diagram detailing how the sample FLT8-13 was cut from sample FLT8-1.
Equipment
310 CP
NAME
Diamond band saw
TYPE
Exact
BRAND
-
SKU
LINK
Cutting the edge angle of tool sample FLT8-13.
b) To avoid catastrophic breakage of the edge during experiments, the leading edge of tool sample FLT8-13 is chamfered at 45 ° . The same protocol was also applied to FLT8-1 in Schunk et al. 2021.
Equipment
310 CP
NAME
Diamond band saw
TYPE
Exact
BRAND
-
SKU
LINK
Chamfering the edge of tool sample FLT8-13.
Tool sample FLT8-13 has the following dimensions:
24.4 mm length
24.5 mm width
8.4 mm thickness
Side corresponding to the dorsal side of the standard saw-cut tool samples. The active edges are at the top of the image. On the left is sample FLT8-1 and on the right is sample FLT8-13.
Cleaning
After sample preparation, the saw-cut tool samples are cleaned to remove any residues that accumulated during preparation:
1. Tool samples are rinsed with tap water.
2. Tool samples are individually packed in plastic bags filled with demineralised water and a surfactant:
100 mL Cleaning solution
1 Mass / % volume
Plurafac LF 901BTC Europe GmbH, Rheinpromenade 1, D-40789 MonheimCatalog #-
3. The bags are suspended in a preheated ultrasonic bath for 5 minutes at 100 KHz.
Equipment
Heated ultrasonic bath
NAME
Sonorex Digitec DT255H
BRAND
62083
SKU
00:05:00
40 °C
4. Lastly, the tool samples are rinsed in their plastic bags with purified water.
The cleaning protocol for the knapped tool samples was simpler as there are fewer residues produced during their preparation. The edge of each blade was treated with acetone applied with cotton swabs.
Acetone ≥99.5 %Carl RothCatalog #5025.6
Fibers from the swabs were removed with an air compressor.
Equipment
480W Silent Flüsterkompressor Druckluftkompressor
NAME
Modell: 1-480-9
TYPE
IMPLOTEX
BRAND
Artikelnummer NEW-325
SKU
5m
Contact material
Contact material
Natural contact material
A slab of pine wood (Pinus sylvestris) with the following dimensions is used as a contact material:
300 mm length
165 mm width
20 mm thickness
Pine wood is used as a contact material for the following tool samples:
- Saw-cut flake tool FLT8-13
- Knapped blade tool FLT13-12
After the first set of experiments, circular marks along the cut groove are added with a center punch to aid in 3D contour matching (step #7.2 and #9.5).
Wood slab (OFA-WP1) with experimentally produced grooves and center hole punch markings. The upper groove corresponds to standard-cut flake tool sample FLT8-13 and the lower groove corresponds to knapped tool sample FLT13-12.
Standardised synthetic contact material
A synthetic bone plate Modified bone-like polyurethaneSYNBONE®Catalog #PR0114 with the following dimensions is used as a contact material:
250 mm length
250 mm width
6 mm thickness
75 Shore hardness D (+/- 5)
Synthetic bone (BP) is used as contact material for the following tool samples:
- Standard cut flake tool sample FLT8-1 (from Lisa Schunk et al. 2021)
- Knapped blade tool sample FLT13-1
After the first cycle of experimentation, circular marks along the cut groove are added with a center punch to aid in 3D contour matching (step #7.2 and #9.5).
Synthetic bone plate (OFA-BP1) with the experimentally produced groove (lower) and center punch markings for knapped tool sample FLT13-1.
Coordinate system
Coordinate system
1d
1d
Coordinate system
A coordinate system is created with ceramic beads for each tool sample. This provides reference points to relocate positions on the sample before, during and after experiments. The coordinate system is calibrated during documentation. The ceramic beads are placed a few millimeters away from the edge of each side of each tool sample.
For more details refer to the following article:
CITATION
Sample Documentation
Sample Documentation
Documentation
Before and after each experiment, the tool samples and contact material are documented. Note that the contact materials are not documented before the experiment because their surface is featureless.
- Acetone is applied to the edge of the tool samples with a cotton swab for intermediate cleaning as needed throughout the documentation.
Acetone ≥99.5 %Carl RothCatalog #5025.6
Photo
Digital photos are taken of each side (dorsal, ventral) of the tool samples to acquire general documentation images.
Equipment
D610
NAME
Digital camera
TYPE
Nikon
BRAND
-
SKU
Objective:
AF-S NIKKOR 24-85 mm 1:3,5-4,5G ED VR
Automatic focus setting
SPECIFICATIONS
Experimentally knapped blade (FLT13-1) (dorsal) tool sample.
Surface morphology documentation
High-resolution 3D scans are created of both object (tool sample and contact material) of each sample set for archiving measurements. The scanner is turned on one hour before to avoid thermic drift. A small field of view (S-150) with a point-to-point distance of 33 µm and a measuring volume of 110 x 80 x 70 mm using following settings is used :
- The tool samples are scanned with the automatic measuring function and the turntable which takes scans while rotating 360o. When needed, additional single scans are acquired.
- The contour matching function is used for scanning the contact materials at 90o to the contact materials.
- The scans are merged at the working computer using the OptoCat (2020R2) software and exported as STL files.
Example of a 3D scan (here: knapped blade tool sample FLT13-1 before experimentation).
Equipment
smartScan-HE R8
NAME
3D structured light scanner
TYPE
AICON
BRAND
-
SKU
LINK
S-150 FOV, resolution of 33 µm
SPECIFICATIONS
Software
OptoCat
NAME
Hexagon Manufacturing Intelligence Software
DEVELOPER
Overview images
Overview images are acquired for each side (dorsal, ventral) of the tool samples using a digital microscope Smartzoom5. The following steps are followed:
- The sample is calibrated with the coordinate beads using the 1.6x/0.1 objective.
- A 3D image of the edge is acquired with the 1.6x objective using the tile-stitching and z-stack functions.
- Settings: the ringlight brightness is identical for all images and the exposure is adjusted as needed. The blending function is activated to acquire smoother borders between the tiles.
- An EDF image of the edge is acquired and exported as CZI and PNG files.
Equipment
Smartzoom5
NAME
Digital microscope
TYPE
Zeiss
BRAND
https://www.zeiss.de/mikroskopie/produkte/imaging-
SKU
1.6x objective; EDF-stitching images
SPECIFICATIONS
Example EDF image from the dorsal side of knapped blade tool sample FLT13-1 at 2000strokes.
Microwear documentation
Abrasion in the form of polish (i.e., brighter and/or smoother surfaces) on the tool samples is documented with the upright light microscope (Axio Imager.Z2 Vario). The coordinate system is calibrated so that images can be layered on overview images from the digital microscope (step #7.3). The following workflow is followed:
- The coordinate beads are calibrated using the 10x objective when possible. In cases when the working distance is too small, the 5x objective is used.
- All polishes are imaged with low magnification objectives (5x or 10x) to later measure their overall size (step #14). Images are acquired using the tiles and z-stack function where needed.
- Each polished are is sampled with the 20x objective for acquiring detailed images of each polish (step #15). Images are acquired using the tiles and z-stack function where needed.
Equipment
Zeiss LSM 800 MAT
NAME
Confocal Laser Scanning Microscope
TYPE
Zeiss
BRAND
-
SKU
Upright light microscope 5×/0.20, 10×/0.40, 20×/0.70; Bright field; Tiles and z-stack
SPECIFICATIONS
Software
Zen Lite (Blue Edition)
NAME
Zeiss
DEVELOPER
Preservation of the edge
Molds for each side of the tool samples are collected for revisiting the state of the edge prior to experimentation:
- A generous layer of silicone is applied to the edge including the coordinate beads and a microscope slide is pressed onto the surface.
- The silicone and set for 00:04:00
- The slide and silicone are removed.
AccuTrans AB forensic silicone (polyvinylsiloxane)
Collecting sample molds.
Note that for tool sample FLT8-1 (Schunk et al. 2021), a different molding material was used:
Technovit Provil Light regularKulzer GmbHCatalog #66009333
For more information on silicone molding see the following:
CITATION
4m
Cleaning
Cleaning
Cleaning
Right before experimentation, tool samples are cleaned to remove any residues that may have accumulated during documentation, such as from moulding.
The edge is cleaned with acetone applied with cotton swab. Fibers are removed with an air compressor.
Acetone ≥99.5 %Carl RothCatalog #5025.6
Equipment
480W Silent Flüsterkompressor Druckluftkompressor
NAME
Modell: 1-480-9
TYPE
IMPLOTEX
BRAND
Artikelnummer NEW-325
SKU
Experimentation
Experimentation
General settings
2000 strokes of linear unidirectional cutting movements are performed for a total of four sets of experimental material. Note that one sample ran for more than 2000 strokes (FLT13-1) , due to software issues.
- FLT 13-1 knapped blade tool sample; OFA-BP1 synthetic bone plate
- FLT-12 knapped blade tool sample; OFA-WP1 pine wood plate
- FLT8-1 standard cut flake tool sample; BP-I synthetic bone plate (Schunk et al. 2021)
- FLT8-13 standard cut flake tool sample; OFA-WP1 pine wood plate
Experimental setup
A template with the following parameters for unilinear movements was programmed in the modular material tester:
5 kg dead weight
140 mm movement length and 170 mm movement length for sample FLT8-1
600 mm/s speed
4000 mm/s2 acceleration
10 Hz sampling rate
Equipment
Modular material tester
NAME
Inotec AP
BRAND
-
SKU
LINK
Recorded values with the time stamps: for each drive: position, speed; penetration depth with extra sensor; applied force with extra sensor; friction with extra sensor
SPECIFICATIONS
Setup sample set
The synthetic bone plate is clamped in a custom-made sample holder and fixed with a screw in the middle of the bone plate. Wood contact material is fixed with four screws on each corner.
The knapped tool samples are fixed in the sample holder (SMARTTESTER®) with their sample clamps. Then, the sample holder (SMARTTESTER®) is orientated by rotating the y-axis to create the most amount of contact between the tool sample and the contact material, which depends on the curvature of the edge of the tool sample.
Tool sample FLT13-1 and bone plate OFA-BP1 fixed in the SMARTTESTER® as described above.
The standardised saw-cut tool samples are clamped in the sample holder (SMARTTESTER®) and manually oriented to create a 90 ° angle between the active edge of the tool sample and the contact material.
Tool sample FLT8-13 and wood plate OFA-WP1 fixed in the SMARTTESTER® as described above.
Program cutting motion
The program is identical for each experiment and was adopted from Schunk et al. 2021:
CITATION
The program settings are listed here:
a) Vertical movement in the z-axis to start.
The z-value of the starting point is defined as follows: The z-drive is moved down slowly until the edge of the tool sample is in contact with the bone plate. 5 mm are added to the position of the z-drive to allow the sample to penetrate the contact material.
b) Linear movement in the x-axis for a total of 140 mm . Tool sample FLT8-1 travelled 170 mm .
c) Upwards vertical movement in the z-axis approx. 20 mm . At this point, no contact is between the tool sample and the contact material.
d) Linear movement in the x-axis to the starting point.
e) Repeat loop for a total of 2000 strokes
Note that for each experiment, five CSV files are exported corresponding to each recorded channel:
- Applied force in [N] as measured by the force sensor in the sample holder.
- Friction in [N] measured by the force sensor on the stage and the contact material.
- Penetration depth in [mm] as measured by the distance sensor in the sample holder.
- Position in [mm] of the x-drive (travel range).
- Velocity in [mm/s] of the x-drive.
FLT13-1_cutting_template.Smart72KB Run experiment
After both the tool sample and the contact material are fixed in the SMARTTESTER®, the program is run for a total of 2000 cutting strokes.
To avoid lubrication between residues from the contact material and the tool samples, these are removed manually with an air compressor every 50 strokes.
Equipment
480W Silent Flüsterkompressor Druckluftkompressor
NAME
Modell: 1-480-9
TYPE
IMPLOTEX
BRAND
Artikelnummer NEW-325
SKU
3D scan of experimental setup
The relative position of each tool sample and contact material is scanned in situ (i.e., in the position of the starting point of the linear trajectory) directly after experimentation. This step is necessary for acquiring a proper alignment of the individual 3D scans (step #7.2) and an identical trajectory of experimentation in the OFA software (step #15). The Aicon 3D structured light scanner with a small field of view (S-150) is used for taking a series of single scans from varying angles by moving the scanning mount around the SMARTTESTER®.
Equipment
smartScan-HE R8
NAME
3D structured light scanner
TYPE
AICON
BRAND
-
SKU
LINK
S-150 FOV, resolution of 33 µm
SPECIFICATIONS
Scanning setup (here: knapped tool sample FLT13-12 and wood contact material OFA-WP1).
Cleaning
Cleaning
Cleaning
A cleaning solution is added to an ultrasonic bath, wherein each sample tool is submerged after experimentation to remove residues.
4 L Tap-water
4 mL Plurafac LF 901BTC Europe GmbH, Rheinpromenade 1, D-40789 MonheimCatalog #-
Equipment
Heated ultrasonic bath
NAME
Sonorex Digitec DT255H
BRAND
62083
SKU
40 °C
00:05:00
Tool sample FLT13-1 suspended in the ultrasonic bath.
Then the edge is dried with acetone applied with cotton swabs. Cotton fibers are removed with an air compressor.
Acetone ≥99.5 %Carl RothCatalog #5025.6
Equipment
480W Silent Flüsterkompressor Druckluftkompressor
NAME
Modell: 1-480-9
TYPE
IMPLOTEX
BRAND
Artikelnummer NEW-325
SKU
5m
Screening
The cleaned tool samples are screened under a stereo-microscope to check for any possible residues from experimentation.
Equipment
Leica M420
NAME
Stereomicroscope
TYPE
Leica
BRAND
-
SKU
1.25 x 10 magnification
SPECIFICATIONS
Clean contact material
Contact materials are cleaned by removing abraded material in the cutting groove with an air compressor.
Equipment
480W Silent Flüsterkompressor Druckluftkompressor
NAME
Modell: 1-480-9
TYPE
IMPLOTEX
BRAND
Artikelnummer NEW-325
SKU
Repeat documentation
Repeat documentation
Post-experiment documentation
After experimentation and cleaning, all tool samples are documented.
7
Micro use-wear image processing
Micro use-wear image processing
Image processing
Overview images of the tool samples generated from the digital microscope (step #7.3) and images of micro-wear (step #7.4) are processed using the ZEN Connect add-on for ZEN Desk add-on (v3.5 HF 9) from ZEISS.
Software
Zen
NAME
Zeiss
DEVELOPER
Raw data from the upright light microscope (Axio Imager.Z2 Vario) micro-wear documentation are processed as follows:
- All microscope image acquisitions are imported in ZEN Desk for batch processing.
- The extended depth of focus (wavelets method without Z-Stack alignment) is applied as a batch process to microscope image acquisitions containing a z-stack.
- Acquisitions that contain multiple tiles are additionally stitched (no edge detection, minimal overlap = 5%, maximum shift = 10%, optimized comparer and best global optimizer) in batch.
Next, all image data (i.e., overview images and use-wear documentation as described above) is processed as follows:
- All data for one side of a tool sample is imported and a project is created.
- Since coordinate beads were calibrated during acquisition in both microscopes, all images can be aligned. A sample holder is created in the project by setting a total of three markers, corresponding to the location of the coordinate beads relative to the microscope stage. The sample holders are created based on the upright light microscope images and the distance between the markers is calculated as follows:
X1–2 = Xmarker2 – Xmarker1 and Y1–2 = Ymarker2 – Ymarker1
- After the marker positions are set on the coordinate beads, the overview image is aligned using the translate function. The overview images needed some manual alignment because of distortion due to tilting of the knapped samples.
Alignment of tool sample FLT13-12 with superimposed use-wear acquisitions.
Alignment of tool sample FLT13-12 using the calibration beads. The sample holder is orange and the pink Ls are the markers of the sample holder.
Measure micro use-wear
Areas of micro use-wear (polish) are marked using the polygon measurement tool to acquire an estimation of the surface area of polish. The following criteria is used for marking use-wear:
- Polish is clearly differentiable from the surrounding rock.
- Polish is bright or very bright.
- Polish is continuous.
The surface area estimations are recorded manually in a CSV table.
Example of a selected use-wear area.
3D Model processing
3D Model processing
3D Model processing
The 3D models of each tool sample and contact materials (step #7.2) and the alignment scans (step #9.5) are processed for further use in the CloudCompare (v. 2.13.alpha, 2023) and Occlusal Fingerprint Analyser (OFA, version 2.1) software. Here, the GOM Inspect (v.2.0.1) software is used.
Software
GOM Software
NAME
Zeiss Quality Suite
DEVELOPER
Process 3D models for CloudCompare
1) Align 3D models
For macro use-wear (i.e., edge damage) documentation in CloudCompare, the 3D model of each tool sample before experimentation (0 strokes) and after experimentation (2000strokes) acquired in step #7.2 are processed. The workflow is as follows:
- One 3D model of a tool sample (e.g., FLT13-1 at 0strokes) is imported in GOM Inspect software as a mesh. The coordinate system is set using the set matrix function. The edge of the tool is orientated along the x-axis. The file is exported as a STL file.
- Next, the 3D model is re-imported into the software as a CAD (i.e., LFT 13-1 at 0strokes) and the second 3D model as a mesh (i.e., FLT13-1 at 2000strokes). The mesh file is aligned to the CAD using the pre-alignment and local best-fit functions. The aligned mesh is exported as an STL file.
2) Clean 3D models
The 3D models from step #13.1 are cleaned by removing additional data, filling holes and deleting mistakes. The following workflow is followed:
- The 3D models are uploaded as a mesh and cropped to remove excess and unnecessary data using the delete-by-plane function. The meshes are cropped so that only the edge of the tool sample in question is left.
- Any visible mistakes (e.g., a triangle sticking out on a flat surface) in the mesh are removed using the delete selected 3D function.
- Holes in the mesh are filled using the close holes automatically and close holes manually function. Regarding the close holes automatically function, a maximum hole size of 10 mm is selected and 1000 is selected for the maximum number of edges.
- Mistakes in the mesh are corrected using the eliminate mesh errors function.
- The cleaned meshes are exported as STLs.
Process 3D models for OFA
1) Align 3D models
The 3D models of each sample (step #7.2) are aligned to the 3D model of the relative position (step #9.5). This is necessary for creating a trajectory in the OFA software that is identical to experimentation. The workflow is as follows:
- First, the 3D model of the relative position scan is imported as a mesh. The mesh is set using the set matrix function. The cutting groove is orientated along the x-axis, the y-axis is orientated along the edge of the contact material and the z-axis is orientated along the face of the tool sample. Then, the origin is translated to be placed at the start of the cutting groove. This alignment is necessary for setting accurate scene path points in OFA (step #15). The mesh is exported as an STL.
- Next, the 3D model of the tool sample and contact material (step #7.2) are aligned one at a time to the above-orientated mesh. The orientated mesh is uploaded as a CAD and the sample 3D models (tool sample and contact material; one at a time) are imported as a mesh in the software. The tool sample mesh is aligned with the pre-alignment and local-best-fit functions, whereas the contact material mesh is aligned with the 3-point-alignment function. The 3 points are placed on prominent features of the contact material surface such as the center-punch marks. The deviations are noted before the meshes are exported as STL files.
The cutting groove on wood plate OFA-WP1 oriented along the x-axis with the origin at the starting point of the cutting groove.
Tool sample FLT13-12 is aligned on its relative position scan.
Note that for FLT8-1 and BP-1, a 90 ° angle is created between the ventral side of the tool sample and the contact material for alignment. This angle corresponds to the experimental setup from Schunk et al. 2021 where no alignment scans were taken.
2) Clean 3D models
The aligned 3D models of the tool sample and contact material are cleaned by removing additional data, filling holes and deleting mistakes in the mesh. The following workflow is identical to step 12.2. Note that for the contact material, the mesh is cropped so that only the cut groove is left.
13.2
3) Create contact between 3D models
Finally, contact between each set of cleaned 3D models is created as follows:
- First, the 3D model of the contact material from step #13.4 is uploaded as a CAD in the software. The 3D model of the tool sample is uploaded as a mesh.
- The mesh of the tool sample is lowered on the z-axis to create contact with the contact material CAD. The mesh is set using the set matrix function. The final z-axis position of the tool sample mesh corresponds to the z-axis position of the experimental setup. The tool sample mesh is exported in the STL file format.
FLT13-12 is lowered to OFA-WP1.
Macro use-wear documentation
Macro use-wear documentation
CloudCompare
The C2M tool in CloudCompare is used for comparing surface deviations from mesh to mesh between each tool sample model before (0strokes) and after (2000strokes) experimentation. The data produced from this gives a comparison of the meshes before and after experimentation and therefore a visualization of edge reduction. A similar workflow to that of Nora (2021, 149) is followed and described below.
Software
CloudCompare
NAME
v2.13.alpha [macOS 64-bit] Compiled with Qt 5.15.2 License: GNU GPL
DEVELOPER
CITATION
LINK
-- First, the pre- and post experimentation STL files (step #13) of each tool sample are uploaded to CloudCompare. The models are aligned by selecting both meshes and using the match bounding-box centres and fine registration (ICP) functions under the registration tab.
- Next, the meshes are compared by selecting both and using the cloud/mesh distance function under the distance tab.
- The properties of the “registered” mesh are changed by making the colour scale visible.
- Comparison data is fetched by selecting the “registered” mesh and exporting the histogram.
- The colour scale toggle is activated and the full-screen 3D view is entered to acquire screen-shot images of the compared meshes.
Occlusal Fingerprint Analysis (OFA)
Occlusal Fingerprint Analysis (OFA)
Occlusal Fingerprint Analysis
The experimental trajectory is simulated in the Occlusal Fingerprint Analyser (v.2.1) software to calculate contact areas as a comparison to the observed use-wear. The contact material (OFA-BP1, OFA-WP1) is static while each corresponding tool sample is moved in the cutting groove. The trajectory corresponds to the last (2000th) cutting stroke from experimentation. The workflow is as follows:
- Each tool sample and the corresponding contact material STL. files (step #13) are loaded in place in the OFA software. File > load model.
- A minimum of three scene path points are set which direct the tool sample along the cutting groove. Scene tree > select tool sample > add point to path. From this position, the scene path points are translated by using the translation function. Scene tree > select scene path point > right click > translate element.
- The first point is translated positively on the z-axis and negatively on the y-axis. The negative y translation is necessary to avoid the tool getting stuck at the cutting groove's starting point.
- The second point always corresponds to the start position of the tool sample in the groove.
- The third point is always at +140 mm on the x-axis which corresponds to the cutting length. For FLT8-1, a cutting length of 170 mm was set.
- Depending on the topography of the tool sample and contact material surface, it may be necessary to set further points to direct the tool sample to move in the cut groove.
- The maximum degree of break free is set to 100. Project > settings > trajectory > break free > maximum degree for break free.
- The default setting for set distance of 0.2 mm is used. Project > settings > collision > set distance.
- A step distance of 0.5 is set. Collision path > step distance.
- The trajectory is run using the start button. Collision path > start.
Software
Occlusal Fingerprint Analysis (OFA)
NAME
DFG research group FOR 771
DEVELOPER
Trajectory simulation in OFA of tool sample FLT13-12 on wood plate OFA-WP1.
Collision groups are seen in the table on the left side.
Imaging contact areas
The show collision distance function gives a view of how close the collision between the two models is as a gradient. This function is activated and images with the location of contact areas on the surface of each tool sample are acquired using the grab image function. The acquisitions are exported as PNG files.
Export diagrams and reports
After each collision and trajectory, data on contact areas are collected by exporting a CSV table of the collision groups and line charts via the diagram function.
SMARTTESTER® data analysis
SMARTTESTER® data analysis
Data Analysis
All CSV files with experimental data (step #9.3) are combined into one CSV file. The sensor data recorded throughout the experimental is then analysed in R.The analysis includes descriptive statistics and plotting the variables velocity, force, penetration depth, and friction data. All packages used are cited in the R script (see #17).
Software
R Studio Desktop
NAME
The R Studio, Inc.
DEVELOPER
Results
Results
All data produced during this pilot study can be accessed here: DOI:
https://doi.org/10.5281/zenodo.8268058
Citations
Step 14
D. A. C. Nora. The role of lithic raw materials on tool performance and use: The efficiency and durability on stone tools edge.
-Step 2.1
L. Schunk, I. Calandra, W. Gneisinger, J. Marreiros. Past human stone tool performance: experiments to test the influence of raw material variability and edge angle design on tool function
https://www.protocols.io/view/past-human-stone-tool-performance-experiments-to-t-bufvntn6/Step 6
I. Calandra, L. Schunk, A. Rodrigues, W. Gneisinger, A. Pedergnana, E. Paixao, T. Pereira, R. Iovita, J. Marreiros. Back to the edge: relative coordinate system for use-wear analysis
https://doi.org/10.1007/s12520-019-00801-yStep 7.5
L. Schunk, M. Weber, I. Calandra, W. Gneisinger, J. Marreiros. Comparative Study of Silicone Moulding Materials in Archaeology and the Forensic Sciences
http://dx.doi.org/10.13140/RG.2.2.26648.67845 Step 9.3
L. Schunk, I. Calandra, W. Gneisinger, J. Marreiros. Past human stone tool performance: experiments to test the influence of raw material variability and edge angle design on tool function.
https://www.protocols.io/view/past-human-stone-tool-performance-experiments-to-t-bufvntn6