DIGITAL TWINS | DATA CAPTURE METHODS REALITY CHECK Creating a digital twin will help maintain a building, but how can existing data be captured? Arups Derek Lawrence explores three methods Digital information of the Solihull Arup Campus caught using a 3D camera K eeping a digital record or twin of the design, construction and occupation phases of a building is one of the key recommendations in Dame Judith Hackitts post-Grenfell report into Building Fire Safety Regulations. A chapter of her report is dedicated to the golden thread of building information. It echoes the challenges faced by many industry professionals when it comes to the effective handover of information after construction and the maintenance of records during the buildings life. Among Dame Judiths other recommendations are having open and non-proprietary formats for digital records, and giving responsibility for transferring and updating information to a duty holder for the life-cycle of a building. For a new-build design, it should be relatively straightforward to ensure the digital history of a design passes usefully into the hands of the operator but how do you even start to create a digital twin for an existing building with as built information that might be 30 years old and poorly maintained? That was a question I asked myself when I began to focus solely on improving existing buildings. For a start, what is a digital twin? While it can be said to be a computerised version of something that exists in the physical world, there is no definition of how computerised something needs to be to reach the increasingly desirable digital twin status. Is a building information model (BIM) a digital twin? What about a tagged PDF plan layout? Depending on what you read or who you speak to, you could conclude they are or they are not. In 2013, I started working for a large real-estate services company, having just witnessed the process of creating the governments BIM level 2 exemplar project, HMP Cookham Wood. I was ready to tell everyone about the exciting potential of BIM, but two questions I kept facing in my new role were: What is BIM and how will investment in it pay back? Unable to give a satisfactory reply at the time, I decided to seek answers by trying to create a digital twin and I started with the question whats in our building and how do we capture it. This sparked my interest in reality-capture techniques, and the routes to, retrospectively, creating a digital twin are listed below, in the order that I discovered them. LiDAR and trace In 2013, light detection and ranging 40 November 2019 www.cibsejournal.com CIBSE Nov19 pp40-42 Digital twin.indd 40 25/10/2019 16:06