Digitaler Donnerstag

How Jena Plans in 3D – What Happens When a New Building Is Constructed?

Let’s imagine: A new building is to be constructed in Jena. Maybe apartments, maybe a school, maybe an office building.

Before the first excavator rolls in, many questions need to be answered: Does the building fit in this location? How tall can or should it be? What will people see from there in the future? Will it cast shadows on neighboring buildings? And how will this change the cityscape?

To address such questions, our colleagues in urban planning and urban development have long since moved beyond relying solely on traditional maps and construction plans. They can integrate planned changes directly into a three-dimensional model of Jena’s urban landscape and explore different options. 

In a building permit process, many different aspects must be examined—such as fire department access, setback requirements, or public infrastructure. The 3D view adds a spatial perspective to this assessment: it shows how a planned building fits into its immediate surroundings. This makes it a crucial component of the overall planning process.

First, determine where construction will take place

Every planning process begins with the property. Using the city’s internal geographic information system, planners can first examine the surroundings of a property in detail. QGIS and the QGIS Web Client are open-source geographic information systems and the specialized software that the city administration uses to process and link spatial information.

This allows them to first assess the initial situation: How tall are the neighboring buildings? How does the terrain rise or fall? What streets, squares, or open spaces are located in the vicinity? What may still seem abstract on a flat map becomes much clearer in the three-dimensional view.

What happens if a building stands here?

Now the first planning idea comes into play. A simple building model can be placed directly into the 3D model. Its height, location, and shape can be adjusted. This allows different variants to be compared with one another at an early stage.
This gives planners a spatial impression of how a new building might fit into its surroundings.

What else can you actually see?

A new building doesn’t just change the location where it’s being built. It can also affect existing sightlines—such as views of other buildings, streets, or landscapes.

Such sightlines can also be examined in the 3D model. This reveals the potential effects a planned structure could have on its surroundings.

Where does the shadow fall?

The sun’s path—and thus the amount of sunlight reaching individual buildings or areas—can also be tracked in the 3D model. A taller building can cast a shadow over a courtyard, a playground, or neighboring buildings. In the 3D viewer, the shadow cast can be simulated for different times of day: What does the shading look like in the morning? What happens at noon? And how does it change over the course of the afternoon?

If a photovoltaic system is to be installed on the new building, the three-dimensional representation can also be helpful. The location and orientation of the roof surfaces, as well as potential shading, can be examined. This provides a basis for addressing questions regarding a building’s solar potential.

In the future, the lighting simulation is also set to be further expanded. Then, among other things, defined light sources could be displayed in the 3D model.

Does the building fit into the site?

Jena is not a flat city. Even today, heights, distances, and areas can be measured in the 3D model. This allows planners to check, for example, how tall a building is in relation to the terrain or what distances exist between different objects.

In the future, this will become even more vivid: The terrain model could be color-coded so that differences in elevation are visible at a glance.

Clearance zones could also be simulated in the future. This would allow for the early identification of areas around a planned building that must be kept clear due to building code requirements.

What’s Next

The new solution was developed as part of the Jena Smart City Project in collaboration with the Smart Cities pilot projects in Detmold, Frankfurt am Main, and Wolfsburg.

The 3D city model is undergoing continuous development. Planned features are intended to create additional capabilities. These include the integration of point clouds from drone flights, more detailed measurement and dimensioning functions, the visualization of elevation differences, and the simulation of building setback areas.

From the Initial Idea to the Final Plan

The example of the new building demonstrates how versatile a 3D city model can be in urban planning. It allows many questions to be addressed earlier and, above all, in a more visually intuitive way.

This benefits not only the experts in the administration. It also creates added value for citizens: The more comprehensibly a plan can be presented, the easier it is to understand what might change in their own city.

The 3D city model thus creates a common language: lines on a map become buildings, abstract elevation data gives rise to a spatial impression—and a plan on paper becomes a vision of what Jena might look like tomorrow.

Do you have questions about this or another DigiDo post? Please feel free to contact us; we look forward to your feedback.