The Building Conservation Directory 2023

42 T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 3 | C E L E B R AT I N G 3 0 Y E A R S C AT H E D R A L C O M M U N I C AT I O N S BIM AND THE DIGITAL REVOLUTION KATIE STEELE D IGITAL TECHNOLOGY has seen a huge amount of focus over the last couple of years, compounded by the necessity to do almost everything remotely through the COVID-19 pandemic. With funding streams following suit to help organisations build the resilience and creativity digital upskilling can foster, Museums and Heritage Advisor reported in 2020 that adoption had been ‘turbocharged’. Building information modelling (BIM) is one digital solution that has transformed the architecture, engineering and construction (AEC) industries, but despite all the interest, BIM has yet to have similar impact in the heritage sector. Widespread adoption has been stymied not only by its cost and specialist skills requirement, but also by its perceived relevance to conservation contexts. This, however, is all about to change. Historic England’s latest guidance on BIM represents a turning point, framing the technology such that it could catalyse a complete revolution of heritage management. VALID SCEPTICISM ABOUT BIM FOR HERITAGE To understand the scepticism surrounding BIM, and why it can finally be banished, it’s worth revisiting the fundamentals of what it is, and why it’s suffered teething problems. BIM emerged as its own distinct field of 3D computer aided design as CAD evolved from volume-based to object-based modelling, wherein digital replicas of a building’s components are used to ‘build’ the building virtually. The components have information attached or ‘embedded’ in them which is accessible via the model interface. The embedded information can be anything, from carbon footprint to servicing requirements. Collectively this enables analysis throughout the building’s lifecycle so it can be designed and managed with reduced financial and environmental cost. The information is contributed to the model by all project stakeholders, enabling coordination and collaborative design so all have access to the latest information, and features such as clash-detection help avoid unexpected issues on site. Over time, the model becomes a repository and viewer for information about the building’s maintenance, refurbishment and even demolition in perpetuity. The potential for conservation is therefore clear. Such data management and exchange capabilities are essential to managing the complexity of historic buildings’ upkeep, adaptation, and specialists’ contributions. Historic England’s first guidance on BIM was published in 2017. Covering best practice, standards and advantages of creating data enriched, virtual component models, it offered practical advice on both the applicability and commissioning of BIM for heritage projects. This provided a basis for sector adoption, enabling professional services to be engaged for BIM creation – where budgets and awareness allowed. Nonetheless, fundamental challenges in using BIM for historic building projects prevent the rapid rollout of this technology across the sector. Model creation involves undertaking detailed digital (laser or photogrammetric) surveys, and virtual components are then ‘built’ to the scan data as accurately as possible, which requires specialist equipment, software and skills. These capabilities are also needed to access and maintain the digital asset beyond the project. For new-build projects, virtual components are readily available in BIM software, libraries or from manufacturers who want designers to specify their products. However, for the conservation field the majority of these do not represent the components commonly found in historic buildings accurately enough, if at all. Although libraries of heritage elements have been created, high numbers of bespoke components are nonetheless needed for models to be representative. Many aspects of the workflow have been improved: most significantly perhaps, 3D data capture capabilities with laser scanners are now so commonplace that even some iPads are equipped with them. However, huge amounts of data still have to be stored, processed and annotated, not to mention managed, made accessible and updated thereafter by any future actors in the building’s conservation. Here, automation through the application of artificial intelligence (AI) presents promising and exciting developments. Historic Environment Scotland and the universities of Edinburgh and Herriot Watt have created an automatic facade segmentation algorithm which detects masonry and pointing in rubble stone walls from scan data, for example. Nonetheless, BIM in its ‘traditional’ form remains attainable only where the BIM evolved from 3D CAD and is object-based: digital replicas of buildings’ components ‘build’ it virtually, with information attached to them and accessible via the model interface. This can be anything, from carbon footprint to servicing requirements, and enables analysis throughout the building’s lifecycle. (Image: Katie Steele)