When Pope Francis visited Philadelphia in 2015, the city faced challenges regarding security.

This was particularly the case as around 20,000 people from 100 countries attended the World Meeting of Families.

To address this, around 28,000 images were captured using aerial and ground based photography of street views and building facades. These were fed into software called ContextCapture provided by engineering and construction software provider Bentley Systems to create a detailed and photo-textured 3D ‘reality mesh’ of the city.

This was then combined with simulation software known as LumenRT (also from Bentley) to simulate people movement, traffic flow, dynamic sunlight conditions and seasonal trees and plants and to evaluate layout options such as road closures and the placement of barricades and video screens.

This is not the only example of reality modelling being used to enhance city planning.

In Helsinki, the city has used 50,000 images and 11 terabytes of data to create a reality model of the entire city which is shared with businesses and citizens in an open data environment. Applications which have arisen from this include a citizen platform which allows residents to explore the likely effect of potential design changes such as the addition of green space in certain areas, an energy an climate atlas which provides residents with building specific information about energy and water usage of Heka Oy’s rental buildings and a digital twin of the Kalasatama area which served as a platform for designing, testing, applying and servicing the entire lifecycle of the built environment.

The city is also encouraging residents, businesses and universities to develop their own applications based around the model.

Examples such as these highlight potential uses for reality modelling in cities around the world.

Reality modelling is the process of capturing existing site conditions using photographs and point clouds to provide an accurate, geo-referenced 3D model representation of buildings, assets and cities using reality modelling software. These can be linked with operation and/or engineering data to then create ‘digital twins’ – digital representations of existing buildings, asset, cities or communities.

In an interview at the Year In Infrastructure conference hosted by Bentley in Singapore last October, Sourceable explored uses for reality modelling with Bentley executives Robert Mankowski, Vice President, Digital Cities Business Unit and Benoit Frederique, Director of Product Management – Reality Modeling.

Asked to describe reality models in simple terms, Mankowski talks of a ‘geometrically and visually accurate (digital) representation of reality’.

He says two concepts are critical: geometrical accuracy and visual accuracy. The geometrical accuracy feature of reality models enable users not only to visualise objects but also to measure and understand their geometry and their shape, size and arrangement. Since they are typically based real life photos or scans, meanwhile, 3D reality models are also visually accurate and produce a digital image which looks exactly like the actual object or asset in real life.

Frederique, meanwhile, describes a 3D image which you can navigate in the digital space, What you see is like any normal computer image but is an image of the real world rather than one which is fake or imagined. When using a reality model, Frederique says people can see what people in that location would see with their real eyes.

According to Mankowski and Frederique, potential uses fall into several categories.

On security and emergency planning, reality models and digital twins can be used by fire, police or emergency service departments to plan responses to catastrophes which could occur around major city assets such as transit hubs, stadiums or major public spaces.

Next, reality models can be used to plan renovations or maintenance of existing assets. When redesigning of buildings or re-routing of roads, for example, 3D reality models can enable options to be explored in a way which provides a more intuitive understanding of current topography and conditions. When planning maintenance, the models can provide crews with a realistic visualisation of conditions they are likely to encounter on site.

Another example is stakeholder and community engagement. Where new developments are proposed, information about theses could be overlaid onto a reality model to provide community members with a real-world view of the likely visual impact upon properties or parks.

Finally, there is disaster planning. Here, engineers can use reality modelling to gain a visually and geometrically accurate representation of the likely impact of events such as floods upon critical assets and can simulate different strategies which could be employed to mitigate risk.

Of course, there are risks. Should they fall into the wrong hands, reality models could put sensitive information into the hands of bad actors.

Here, Mankowski says restrictions can be placed on access. Speaking of Bentley’s own offering, he says the company’s cloud based services are based on the Microsoft Azure Cloud which enables many different layers of security for which certifications are needed and allows data to be placed behind firewalls. The Azure cloud also enables countries to prevent certain data from leaving their borders. Singapore, for instance, requires data shared with its citizens to remain within the city/state. Microsoft can do this, Mankowski says, as it has data centres across many parts of the world.

Nevertheless, he says both the value and security/integrity of systems is often maximised in an open sharing environment.

“In the case of Helsinki, they believe in open data,” Mankowski says.

“They are making their data open. That is leading to innovations by universities and other partners.

“Bentley Systems has made the platform an open source platform.

“Studies have shown that open source is a good way to ensure security of a system. It’s under scrutiny. Lots of people can contribute to the security of that.”