Text by Jeroen Vanthournout, Intercommunale Leiedal (ICL); images by Intercommunale Leiedal
Spatial challenges are becoming increasingly complex. Climate adaptation, urban densification, mobility, heritage, and energy each bring their own datasets, models, and expectations. In spatial planning, there is no such thing as absolute truth, only perspectives. Data is interpreted differently by the various stakeholders and experts involved, each from their own discipline, interests, or imagination. This often gives rise to parallel realities, which complicates collaboration and puts trust under pressure.
The real challenge, then, lies not so much in the complexity itself, but in the lack of shared understanding. How do you ensure that policymakers, experts from different disciplines, and other stakeholders see the same reality? How do you translate data and technical analyses into clear insights that spark dialogue, imagination, and connection?
Leiedal is convinced that technology alone is not enough. The key lies in creating an insightful narrative within an ecosystem, in which people and services are supported with the right tools. That is why Leiedal developed a framework with a modular toolbox that helps visually clarify the architecture of local digital twins. Call it a form of storytelling, not as a marketing tool, but as a methodology to structure complexity, make it visible and open for discussion, give it shape, and use it as a basis for making targeted, strategic choices.
First deconstruct, then reconstruct
A local digital twin is rarely a single tool. It is not a stand-alone viewer, a separate 3D model, or a database that exists in isolation. Leiedal views a local digital twin as the result of a thorough exercise and deliberate configuration within a broader ecosystem — an ecosystem made up of data sources, models, working environments and interfaces, standards, agreements, users, policy processes, and more. The toolbox facilitates a common language within this ecosystem. As we know, without a common language, there is no common story.
Building a local digital twin starts with a form of deconstruction, in order to properly understand what is at stake. In practice, the toolbox helps break down complex spatial cases into individual elements and position them along three axes in a matrix. Such an element can be a point cloud, an existing digital twin interface, a tree layer, an orthophoto, a BIM model, a spatial implementation plan, a design, and so on.
The position of an element relative to the axes captures, at a glance, which scale level it belongs to, for whom and how it is accessible, and where it is on the spectrum between raw data and usable application
x — Level of usability: indicates how much processing an element still requires, ranging from raw data, to structured or semantic datasets, to working environments, and finally to interactive interfaces where data, models, and functions come together.
y — Level of access: not all data, models, or tools are already available, or equally accessible to everyone. This axis runs from fully open to private. Access is not merely a legal characteristic; it also involves trust, privacy, ownership, and sustainable (commercial) relationships balanced against the flexibility of the ecosystem and its use.
z — Policy level / scale: the administrative and spatial scale at which a built environment is relevant, ranging from project and municipality, to region and province, to national and European level.
This exercise, carried out with the help of the toolbox, forces sharpness on the one hand, and deepens internal understanding of the use case on the other.
A closing note: it is no coincidence that the three axes, together with the whole, correspond to the four frameworks within Twin4Resilience:
x: usability ~ EDUCATION & TRAINING
y: access ~ ETHICS, INCLUSION & DEMOCRATISATION
z: policy ~ GOVERNANCE
the three axes combined = TECHNICAL FRAMEWORK
After this analytical deconstruction comes the reconstruction. The toolbox offers much more than mere classification. We deliberately draw a parallel with chemistry, where elements combine to form molecules. In our methodology too, we deliberately link elements into durable connections. The comparison with chemistry is fitting, because combining elements gives rise to entirely new properties. The lines between the building blocks represent data flows, processing steps, and work processes. They turn a collection of separate blocks into a valuable, connected whole. Through this element-based structure and the connections between elements, Leiedal creates a degree of flexibility that allows it to keep exploring and implementing new technologies, limits the risk of vendor lock-in, and keeps the municipalities firmly in control.
The toolbox in practice
At the regional level, Leiedal had LiDAR data collected via Cyclomedia NV. Through StreetSmart, this provided the basis for a regional digital twin. Initially, the StreetSmart environment brought together true ortho imagery, base maps, 360-degree street panoramas, and street-level LiDAR. By expanding this with Aerial 3D, we evolved into a fully-fledged regional 3D environment. Thanks to algorithms developed by TU Delft (NL), we can automatically generate usable 3D datasets from raw LiDAR data for use cases across the 13 municipalities in our operating area.
To this basic information, we then add other relevant elements, ranging from heritage values of buildings, tree layers, and spatial policy frameworks (RUP), to BIM models. Within this carefully assembled spatial environment, it becomes possible to design and develop future scenarios, all within the same digital ecosystem.
Naturally, this approach also calls for clear human processes and collaboration with and between the various stakeholders: policymakers and experts from different disciplines, but also citizens, developers, and others.
A crucial link in Leiedal's approach is the visual translation that makes abstract information tangible. This visual translation facilitates imagination, design, and simulation. Leiedal sees this as a precondition for sharing information, co-creating, and showing the impact of future scenario, in short, for involving others in the process. Because policymakers, experts, and other stakeholders don't just want to understand what already exists. Above all, they want to see what could be, or what the consequences of certain interventions might be.
By integrating data, urban design, and architecture into a single multidimensional model, a living 4D environment emerges. The result is powerful: seeing becomes believing. Here, we draw on a concept from Willem-Jan Renger (HKU): "Préjà vu, the act of envisioning something that hasn't happened yet."
In this approach, the local digital twin is not an end product, but a continuous working platform based on linked elements. After all, the environment it aims to duplicate, represent, or simulate is itself constantly in motion through planning, redesign, and change. This allows the full potential of design and imagination, policy, communication, and participation to be realized, while enabling adjustments based on the democratic process or consensus of the moment.
By approaching complex spatial issues through the toolbox, Leiedal creates powerful instruments for the 13 cities and municipalities in South-West Flanders. This is what sets Leiedal's approach apart:
analytical and narrative
technical and human
precise and understandable