By bringing models into 3D, architects and urban planners are better equipped to solve challenges around shifting landscapes, climate change, transportation, and more.
While a digital twin by definition is any virtual copy of a physical asset, process or system, an urban digital twin is a virtual representation of an entire urban environment’s physical assets. Urban digital twins play a critical role in the larger global movement toward smart cities. A “smart city” is a community that uses electronic means to collect valuable data surrounding the use and performance of its utilities, mobility patterns, and infrastructure by using tools like Internet of Things (IoT) sensors to record activities and changes in the urban environment. Urban digital twins often serve as the systems within which this data is represented and visualized. They are created by aggregating large sets of map and model data, visualized in real-time.
Because of this, urban digital twins offer an ability to look at the future state of an urban environment in a more accurate context than a collection of traditional building models would allow. They are also helping designers reimagine and further democratize the planning process. According to ABI Research, more than 500 cities around the globe will have deployed digital twins by 2025. Currently, many cities are actively making the effort to digitally replicate their urban landscapes and explore the roles digital twins will play in their communities.
One of those cities is Trondheim. The fourth largest city in Norway, Trondheim is located on the shore of Trondheim Fjord. Founded by Viking King Olav Tryggvason in 997, the city has a rich Nordic history. Like many cities around the world, Trondheim’s geographic features necessitate densifying the existing urban landscape to allow for growth. This presents a notable design challenge, especially when coupled with the effort to preserve the city’s longstanding beauty and charm.
In 2020, local architects went to work on modeling a vision for the future of their city in the Trondheim 2050 competition. The competition was a part of the city’s larger effort to create comprehensive strategic plans for its growth across the next several decades, by inviting different perspectives and increasing public engagement with the planning process.
To model what Trondheim might look like in 2050, Martin Vitsø, Geodata Specialist for the City of Trondheim, turned to Unity.
Vitsø led the effort to bring a collection of the teams’ SketchUp models as well as critical geographical information system (GIS) data into Unity Pro to create an accurate and interactive look at the potential future of Trondheim.
Coordinating this effort across architecture teams that use different technical solutions is no small task, and cities face the same challenge on a much larger scale when creating cohesive models. “For this project, we used SketchUp almost exclusively. Teams were given SketchUp models of parts of the city that they would work on, and given instructions to place their own models into these SketchUp models first.”
Martin decided to independently experiment with Unity a few years ago and this was his first effort to use it at this scale and in a public format.
“Unity was able to handle a big data load,” says Vitsø. “I really liked having the ability to program scripts to take screenshots with high-level resolution and different projections, even 360 degrees.”
The result was a detailed digital view of the city, a 3D vision of Trondheim that allowed viewers to see each team’s proposed buildings and infrastructure changes in context.
Vitsø was also interested in finding ways the Unity models could increase public engagement with the Trondheim 2050 project and invite comments from residents. He experimented with ways to make the existing public maps of Trondheim more interactive and easier to navigate. “The backgrounds in the public response map are all high-resolution single isometric images from Unity. The virtual tour with virtual reality (VR) support is also made from 360-degree images from Unity.” Below you can see where he aggregated comments into a heat map overlaid onto a 3D version of the public map, so teams could easily identify areas of peak interest or concern to the people of Trondheim.
The city’s planning team arrived at a definitive list of residents’ top concerns and aspirations to incorporate into their strategic plans. Residents highlighted where they would like to see increased greenery, public seating, pedestrian zones free of cars, and better access to the Nidelva river that runs through the city.
Responses to the project from both the city and the public were very strong. “City staff members were very happy to bring 3D, VR and an interactive response map into the public participation mix. Generally, community involvement was mostly analog, consisting of public meetups and drawing on printed maps,” Vitsø says.
“This way of doing things can hopefully bring a more diverse crowd to participate in the planning process. City planners have told me that many of the people who participate in conventional means of information sharing already know the process well and would have offered feedback anyway.”
For Trondheim, the 2050 project was only the beginning. “We did not really use the term ‘digital twin’ prior to this project – we’ve always made 3D models of small or big areas in the city when needed. Consequently, we had put more energy into having an effective means of making fresh 3D models from fresh map data instead of keeping and updating a digital twin.”
Vitsø is hopeful that more streamlined data and model sharing is the next wave in the movement toward digital twins and smart cities.
“From my bureaucratic point of view, I’d like to be able to easily share up-to-date contextual digital twins with other municipal, state or private actors. Today, this can require a lot of manual processing, making models a certain way, then combining model data with certain columns in certain databases to fit the need for one specific project. There are efforts being made nationally with regards to 3D modeling and the storing of building information in databases that will concern all municipalities.”
Vitsø and his colleagues in Trondheim are still hard at work looking for new ways to leverage data and propel Trondheim into the future.
“The purpose of a comprehensive digital twin would be to expand the use of a 3D city model to include live sensor data along with select attributes from data registries. For instance, an energy usage analysis for a city might require a 3D city model and a bunch of extra information related to each building. We have all this information, but it’s spread across several databases and requires acrobatics to combine.”
With Unity, users can consolidate their data in one place. Designers and city planners around the world are quickly discovering the power digital twins offer to visualize the impacts of future plans, inform data-driven decisions, and engage the public for remote collaboration.
“I see Unity as the platform for making the visualization products we want to show the public,” says Vitsø. “An engine like Unity offers unique capabilities.”
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