Context 168 - June 2021

12 C O N T E X T 1 6 8 : J U N E 2 0 2 1 JOANNA HULL BIM for heritage asset management Building information modelling (BIM) is finding an important role in the heritage sector, even in conditions so cold that laptops struggle to perform. There is often confusion surrounding the definition of building information modelling, particularly in the heritage sector. BIM is not a new technology: the object-based parametric modelling on which it is based has been used in manufacturing industry for decades. Neither is it a specific type of software, such as Revit. Finally, BIM is more than just laser scanning, point clouds and 3D models. These forms of software and hardware could be considered tools in the BIM process of information produc- tion, management and delivery among project stakeholders across a building’s lifecycle. BIM tools include static and hand-held laser scanners, which use a line of laser light to capture digital data of real-world objects. This is then processed in software and used to construct digital 3D models. The process of photogrammetry or structure from motion uses photographs taken from different locations and angles, and data about the camera’s position, such as coordinates, to gather measurements. With the help of photogrammetry software, the data can be processed to create digital models. Digital documentation The use of BIM tools in the heritage sec- tor to date has had a heavy focus on digital documentation of heritage assets. There are many good examples of heritage assets being digitally documented using laser scanning or digital photogrammetry to create 3D geospatial data sets, or point clouds, and 3D-rendered models. The Rae Project, delivered by Historic Environment Scotland, aims to digitally docu- ment every heritage asset in HES’s care, using laser scanning and a combination of 3D point clouds and photogrammetry to produce highly accurate, detailed and colourised spatial data. Similarly CyArk, a non-profit organisation, has a mission to digitally record, archive and share the world’s most significant cultural heritage. Digital documentation through 3D data sets has a range of benefits: visualisation for planning, development and conservation; disaster risk management; structural and condition monitor- ing; and education, research and engagement. Laser scanning and point clouds have been used for some time to produce both 2D and Terrestrial laser scanning at Stokesay Castle, Shropshire