The Discovery Programme has a remit to research new techniques and technologies which may have potential applications to archaeological research in Ireland. High resolution laser scanning based on triangulation and structured light principles had been assessed in the past but their high cost had restricted their use. However the availability of the NextEngine 3D Scanner HD at approximately a tenth of the price allowed the Discovery Programme to purchase such a scanner.

Although primarily designed as a desk-based scanner it can be mounted on a tripod and so we took the opportunity to test it on a number of sites with a range of 3D depths and resolutions. One of these test sites was Knowth in the Bru na Boinne World Heritage Site where we had the opportunity to use our scanner to record the megalithic art carved into both sides of a large boulder in satellite tomb 14.

The primary aim of the project was to generate a 3D model of the complete stone surface, back and front to prove that the NextEngine scanner could be applied to a subject as large as the stone. The laser scanner used on the project was a NextEngine 3D Scanner HD triangulation scanner (Model 2020i). The instrument was powered by a Kippor Sinemaster 1000 petrol generator and controlled by Scanstudio HD PRO software hosted on a Dell Precision M90 laptop. Data was exported from Scanstudio HD PRO as .xyz files with the bulk of the processing done using Geomagic 12 software.

The final surface wrap was generated in Geomatic 12 software where it could be examined and manipulated to great effect. However, this was not an appropriate deliverable as only users with the software could access the data. We wanted to look at the options for distributing the data in conventional printed formats and also how we could deliver the data in a 3D format which would do full justice to the quality of our model.

For the conventional plan products the problem was how to ‘project’ the irregular stone surface onto the flat page to enable measurements and interpretation to be applied. For this the stone was divided into a number of generalised planes and for each of these an orthoimage produced. A key image located each of the orthoimages of the stone surface. More than one image was created for each plane exploiting the power of Geomagic to use different lighting positions to enhance the clarity of the artwork. The accuracy of these orthimages is clearly dependent on the variation of the stones surface shape but as a tool to aid and record interpretation they have proved extremely valuable.

Dissemination of the data in 3D has been acheived by exporting 3D PDF documents from Geomagic 12, an article on the value of this format will be posted shortly.

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