Picture the kwaliteitsborger at the kitchen table on a wet Tuesday. The Bbl open in one window, the drawings in another, a ruler on the PDF, checking whether that door is wide enough and whether the route to the stair is short enough to still count as a way out. It is careful work. It is also a person reading a rulebook and measuring a drawing by hand, one clause at a time. There is another way to ask the same question, and it starts with the model.
Model-based code checking is a plain idea. A building code is a set of requirements written for people to read. A model is a structured description of the building that a computer can read. If you can express a requirement in the same terms the model uses, the computer can hold one against the other and tell you where the building does not meet the code. The model here is an IFC file. IFC, the Industry Foundation Classes, is the open, vendor-neutral standard for that data, registered as ISO 16739 and looked after by buildingSMART. It is the same format an architect exports from any authoring tool, and it stays readable a decade from now without the software that made it.
From a code written for people to a check a computer can run
The Bbl, the Besluit bouwwerken leefomgeving, is the Dutch rulebook for the technical quality of a building. It has been in force since 1 January 2024, when it replaced the old Bouwbesluit under the Omgevingswet. It sets requirements across a handful of domains: structural safety, fire safety, health, usability, accessibility, and energy. Most of those requirements read as ordinary sentences. A stair has to meet certain dimensions. A door has to give a certain clear width. A fire compartment has a maximum size.
A rule pack is where those sentences become checks. It is a set of rules, each one tied to a specific requirement, written so a machine can evaluate it against the properties and geometry already in the model. Not the whole code. The parts that are genuinely a matter of a measurement or a property, which turns out to be a large share of them. The pack is scoped to one jurisdiction and one framework, the Dutch Bbl in this case, because a rule only means something inside the rulebook it came from.
A pass or a fail, on the element
Here is the part that matters on site. A manual check ends in a note: the corridor on the second floor is too long. Then someone has to find that corridor again. A model-based check ends on the element itself. The engine runs the rule pack over the IFC model and returns each violation against the exact element it concerns, named by its own identifier. Not "a door somewhere is too narrow," but this door, this global_id, this storey.
In BimDossier that violation does not stay a line in a report. It becomes a finding, pinned to the element in the 3D viewer, with the rule it broke attached. You can turn it around, isolate its storey, and see it in place. The result stops being a verdict you have to take on trust and becomes a spot you can walk back to, on screen or on site.
The same method, one jurisdiction at a time
This is where the Dutch rulebook meets a wider picture. Model-based checking is not a Dutch invention. It rests on openBIM, the IFC standard and the neutral body behind it, which the whole of Europe already shares. The method does not care which country's code you feed it. What changes from one country to the next is the rule pack, not the machinery.
That is how the product is built. The rules live in packs scoped by jurisdiction and framework, and the system is designed so a new country is a new pack, not a rebuild. Today the packs we run are the Dutch Bbl and the Wkb. We do not check the Belgian or the German building code yet, and we will not pretend otherwise. But the shape of the thing is European by design, because the standard underneath it is.
What this does not do
A rule pack does not replace the engineer. A full structural calculation, a fire-safety strategy, an energy-performance assessment: these stay expert work, with their own certified tools. What the packs check is the large set of Bbl requirements that come down to a dimension or a property on the model: structural, fire safety, health, usability, accessibility, and thermal. The clauses that need human judgement stay with the people who have it. We would rather tell you where that line sits than blur it.
Where we come in
Under the Wkb you have to prove the work was done right, not just say so. A model-based check gives you a head start. Run the pack early, see which elements fall outside the code while there is still time to fix them, and carry each one as a finding with evidence until it is resolved. When the model is right, the check is quiet. When it is not, you know the exact element to look at. The code was written for people. The proof still sits on your model.