3D technology reinvents property valuation: meet Damien Rohmer

Between scientific discoveries and practical applications, 3D modelling is transforming the way we evaluate and view property. Damien Rohmer, professor of computer science at École Polytechnique, takes us behind the scenes of this technological revolution. Director of the École Polytechnique computer science laboratory (LIX), a long-standing partner of Homiwoo and head of the Vista team, he applies his expertise to innovative projects that are changing our daily lives.

What is a 3D model?

For Damien Rohmer, things are simple: a 3D model is ‘a representation of a shape in a three-dimensional virtual world’. The representations associated with 3D models are diverse. In recent years, they have undergone major developments, providing ever better ways of visualising virtual spaces realistically, as if we were actually there.

Gone are the days when we had to make do with 2D plans that were difficult to interpret. ‘Traditional plans speak mainly to experts and not always to customers’, explains the researcher.

A new way of seeing spaces and their fluidity 

3D technology is revolutionising the way we understand and assess a home: ‘Unlike 2D plans, which require a considerable amount of imagination, modelling immerses us directly in the space as it will be in the future,’ explains Damien Rohmer.  

This immersion instantly reveals essential details: the clutter of a beam in the middle of the living room, the variable ceiling height of a mezzanine or the ease of movement between rooms.

A 3D plan also gives you a better idea of the actual distance to utilities. Estimating the distance as the crow flies can be very simple, but the aim is to predict any obstacles, such as stairs to be climbed, for example.

‘3D modelling could even be used to simulate real-life situations,’ explains the professor: a family with children passing each other in a corridor, elderly people moving around with their mobility aids, or simply several occupants moving around the home at the same time. These analyses, based on techniques used for crowd simulation, could objectively measure the practical quality of spaces.

Light in a 3D model, a precious ally for real estate developers

Lighting simulation is a technique that calculates how light behaves in a virtual environment. Specifically, Damien Rohmer explains that: ‘The algorithms reproduce the path of light rays from their source (sun, lamps) to their interaction with the various surfaces in a space’. Each material (wood, glass, fabric, concrete) reacts differently to light: some reflect it, others absorb it or allow it to pass through.

In a 3D model, these properties are encoded for each surface. The computer then calculates how the light rays react, creating a realistic image of natural or artificial lighting. This makes it possible to accurately predict the lighting ambience of a room even before it is built or renovated.

But the benefits go far beyond this, because with a 3D model, the environment can be virtually modified. Would this room be brighter if we knocked down this wall? Would a window be useful there? Thanks to lighting simulation, it is possible to answer these questions without having to carry out the work. With this technology, it's possible to simulate lighting at different times of day or according to the season.

AI: from model generation to intelligent design proposals

Artificial intelligence is radically transforming the field of 3D modelling as applied to real estate. This technology now makes it possible to generate entire representations of spaces from fragmentary information. By analysing thousands of floor plans and flat configurations, AI algorithms are able to identify patterns of rules implicit in the layout of spaces. ‘Today, with a few partial photos and basic information such as surface area, we can generate a complete and coherent 3D representation of a flat’, the professor enthusiastically explains.

Artificial intelligence does not simply replicate existing models, but proposes the most probable and plausible solutions, taking account of building standards and spatial constraints.

This generative AI approach saves a considerable amount of time compared with traditional 3D modelling methods, which require a great deal of manual work. It also produces more realistic and personalised models. In addition to simple reconstruction, these technologies make it possible to suggest layouts for a given space or propose relevant modifications based on the preferences indicated. 

The human touch remains at the heart of the process

As in all sectors affected by the rise of artificial intelligence, the property valuation profession is evolving rather than disappearing. AI is taking over some previously tedious tasks, allowing professionals to focus on higher added-value aspects.

‘AI reaches into areas that were thought to be the preserve of humans, such as the notion of style or good taste,’ explains Damien Rohmer. ‘Using databases of what humans have created, it is capable of recreating and proposing aesthetic and functional layouts’.

This development opens up new prospects for property professionals. The expert becomes the conductor between the technology and the customer, providing an understanding of human needs that AI cannot fully grasp. They retain their role of strategic advice, technical validation and personalised support. Customers will soon be able to see for themselves the impact of a wall being knocked down or a kitchen being redesigned, but they will still need a professional to validate the technical feasibility, anticipate regulatory constraints or suggest alternatives based on their experience. 

A property valuation revolution

At the crossroads of scientific research and practical applications, these 3D modelling technologies are transforming the way we perceive spaces. For Damien Rohmer, this represents an exciting opportunity to ‘contribute to cutting-edge technological issues that are redefining our daily lives’.

Property valuation, which has long been based on standardised criteria and market comparisons, is now entering a new era in which the value of a property can be assessed with previously unheard-of precision and objectivity. By revealing qualities that were previously difficult to quantify - optimal lighting, traffic flow, potential for redevelopment - 3D modelling considerably enhances the evaluation criteria.

For buyers and sellers alike, this technological revolution brings additional transparency and fairness to property transactions.