Complex inventory in large-scale projects requires a clear basis

Large-scale projects and site developments always follow the same pattern:

The biggest challenge is not the design, but the existing building.

Established structures, different construction phases, missing or contradictory documentation - this is precisely what makes projects in existing buildings so demanding. And it is precisely here that it is decided whether planning works efficiently or becomes unnecessarily complicated.

Three VDE projects show how different these initial situations can be - and why a clear data basis is crucial.

Spisermarkt St. Gallen - established structures in the heart of the old town

A mixed-use building complex is located in the heart of St. Gallen's old town: retail space on the first floor, apartments and offices above.

What appears clear at first glance reveals a very different reality in detail: different years of construction, numerous conversions and a structure that has evolved over the years.

Existing plans are often inadequate in such situations, as they only partially reflect the actual condition.

The 3D survey creates a complete picture of the existing building - including all the geometric features. This is the only way to see how the individual parts of the building are actually connected.

Sunnemärt Bremgarten - from the existing building to a complete BIM model

At the Sunnemärt shopping center, different uses meet directly: a supermarket on the first floor and two residential floors above.

Here, the requirement went beyond a mere inventory: a complete 3D BIM model was created.

This means that in addition to the geometry, additional information from the planning was also integrated. Multi-layered ceiling and floor structures, structural details and other relevant data flow directly into the model.

The result is not just an image of the existing building, but a digital basis that can be used directly in further planning.

Schweighof housing estate in Zurich - precision as a prerequisite for future interventions

The Schweighof estate comprises 69 terraced houses and thus represents an entire residential complex.

The requirements for future conversions have increased significantly as a result of the listed status. Interventions must be precisely planned and carefully coordinated.

In such projects, an inaccurate inventory is not an option, as any deviation can have a direct impact on planning, costs and approval.

The 3D as-built model provides the necessary security here: it forms the basis for correctly understanding existing structures and building future measures on them in a targeted manner.

Why the inventory determines the success of the project

These three projects are different - and yet they have one central theme in common:

Existing buildings are complex, which is precisely why they need clarity.

Typical challenges in existing buildings:

• Established and undocumented structures
• Different planning statuses
• Missing geometric information
• Deviations between plan and reality

Without a reliable data basis, uncertainties arise that permeate the entire project.

A precise 3D as-built model creates precisely this basis. It makes complex relationships visible, reduces the scope for interpretation and enables consistent planning on the same basis.

In the end, it's not about technology, it's about making planning work.

And that always starts with the existing building.