The 3D Models
Several hundred 3D models of stone tools are available in the Museum of Stone Tools for you to explore.
The 3D models are hosted on a platform developed and maintained by Pedestal 3D and licensed to the University of New England in Armidale, Australia. Pedestal 3D was developed to aid online course delivery for university lecturers and to provide a venue for museums and galleries to display and store digitised collections. The platform offers custom tools to augment and extend the traditional classroom experience, including digital calipers for measuring objects and downloading the data as a csv file, tools for lighting and surface texture manipulation, slicing options for making cross sections, and a screenshot application to capture views for use in essays and reports. Key attributes can be shown using annotated pins, which in turn provide a virtual tour of the object, moving from attribute to attribute. The information fields allow direct links to other online resources.
Making 3D Models
The 3D models hosted in the online Museum of Stone Tools were made by a variety of methods.
The best-quality models were made by photogrammetry. This involves taking many photographs of the artefact, from all angles, and stitching them together into a 3D model using specialist software. Since these models were created using photographs, the surface appearance is a close match to the original artefact.
Many of the models were made using specialist 3D scanning instruments. These instruments sweep the object with a laser or structured-light and create the model from the data.
In making a 3D model, millions of points are recorded on the surface of the object. These are converted to a mesh of many flat surfaces, called polygons, in a similar way that a disco ball models a sphere. Because the surfaces are curved, the degree of accuracy of the 3D model depends on how many polygons were calculated by the software.
3D scanning instruments can record surface appearance by recording colour at each location in the point cloud, but the results are less appealing than photogrammetry. For this reason, the models made using 3D scanning instruments are often presented as metallic-looking objects without an attempt to reproduce the surface appearance.
The best 3D models are made using X-rays in a ‘computed tomography’ (or CT) scanner. CT scanners are typically used in medical imaging, but can also be used to produce extremely accurate models of artefacts, without issues of feature-rounding or unresolved hollows. In addition to recording surfaces and attributes in exquisite detail, CT scanners are particularly useful in seeing the insides of objects without damaging them. The Museum of Stone Tools has yet to upload 3D models of stone tools made with a CT scanner, but we live in hope!
The flake scar boundaries on 3D models usually appear slightly ‘rounded’, unlike the crisp features on the actual artefacts. This is due to the difficulties in creating a mesh of flat polygons over such complicated objects. For the same reason, the edges on stone tool 3D models are not as sharp as on the stone tools themselves. Also, it is sometimes difficult to record data in hollows and difficult-to-reach places, and to render shiny surfaces. Although the models are not perfect, and some are better than others, the benefit is that anyone with an internet connection can have a virtual-reality experience with incredible stone tools.
A typical photogrammetric model made for the Museum of Stone Tools is defined by between 10 and 20 million polygons. We have reduced this level of detail to about 400,000 polygons so that the models can be viewed on standard laptops, tablets, and mobile phones. This means that if you attempt to 3D print from these models you may not get an optimum level of detail. A high-resolution version may be available however; contact the Curator for more details
Artefacts vs 3D Models
Pedestal 3D is the best online platform available for drilling down into the details of a 3D object. In fact, some of the manipulations possible with the 3D models—such as the lighting, texture, cross-section, and measurement tools—are difficult or impossible to do on the actual artefacts. But what are the challenges of using 3D models?
Dr Melanie Fillios (University of New England) compared the learning outcomes of online students enrolled in a specialist zooarchaeology class. She compared online students who used only the Pedestal 3D models of bones to students who learned directly from the actual bones in face-to-face tutorials.
Dr Fillios found that the online students had a much better grasp of anatomical details than the students who physically attended the tutorials, because of the way they interrogated the 3D models by zooming in and forensically examining each specimen. However, the students who examined the bones had a better grasp of the bone’s size because zooming into the 3D model of a tiny bone tended to distort the perception of the bone's actual size.
We recommend that you always start your close inspection of a 3D model by carefully considering the object’s size using the scale tools, as described here, and eyeballing the measurement against a physical ruler.
