As part of the Medieval Rural Settlement Project's Roscommon module a large volume of survey data has been gathered with the aim to further our understanding of the medieval landscape. It was in this context that we looked to develop a process of generating virtual reconstructions of some of the principle upstanding structures that had been surveyed with the medieval landscape that would have surrounded them. Roscommon Priory was the first subject selected for this digital three dimensional reconstruction process. The Priory is located on the south end of Roscommon town and was founded in the year 1253 by Felim O'Connor, King of Connaught.

Source Data

Two major surveys were undertaken on the priory and its grounds. The first was a laser scan of the Priory, done using the Trimble GS101 scanner. This survey resulted in a complete 3 dimensional record of the Priory, with over 15 million XYZ positions gathered to represent the surface of the priory. The scan point spacing achieved was 10mm, and at this resolution it was possible to interpolate the individual stonework of the priory from the scan.

A laser scan of the south field of the priory was also completed to generate a detailed surface model of the ground. The other survey technique applied was a geophysical survey of the south field which it was hoped would reveal the footprint of the priory cloister which would have formed part of the priory. All survey data was georeferenced in Irish National Grid co-ordinates using the VRS Now GPS correction service. The image below shows the results of the geophysical survey and the laser scan survey of the south field, with the footprint of the former cloister evident.

The other important component used to reconstruct the priory was historical and contemporary evidence to expand on our view of the Priory as it currently stands. Drawings by Harold Leask from 1960 allowed for the accurate addition of windows into the model, whilst an 18thC antiquarian drawing by Bigari showed us evidence of a cross tower within the priory, and a small entrance on the North West wall of the priory. Plans and images of Sligo Friary were also referenced to help determine how the cloister would have stood.

Digital Model

A digital model of the Priory was generated using AutoCAD. Ortho images were extracted from the laser scan data which were then imported into AutoCAD, retaining their true Irish National Grid coordinates. Also imported into CAD to aid with the model creation was the historic and contemporary evidence, which was correctly aligned to the orthoimages. A universal co-ordinate system (UCS) was then created for each of these orthoimages in the CAD drawing. These UCS's were used as a reference to trace a line-work frame of how we believed the Priory would have stood. This frame was then turned into blocks that form the basis of the reconstruction.

The next piece of software used in the modelling process was 3D studio Max. The CAD blocks were imported into 3DS max where materials assigned included a digital photograph of a portion of the Priory south wall. An image of a portion of the Priory stonework itself was used to try to keep the model as authentic as possible. This was then tiled to cover the whole surface of the Priory walls. The material assigned to the roof was an image of a timber shingle roof, sourced from an image library, which again was tiled to cover the entire roof. Doors, windows and pillars were also added to the model. The resulting model is an accurate 3 dimensional model of the Priory which can be viewed from any angle, based on precise survey data, which is positioned in its correct geographic position.