What should go into a technical AI prompt for a room?
A technical prompt describes the room as numbers, not mood: where each wall starts and ends, where the windows and doors sit, and which furniture is already in place. It is the type of prompt that produces the fewest guesses and the most usable answers.
The short answer: a technical prompt for interior design should include a coordinate system or a clear direction (north, south, and so on), each wall with a start and end point or a length, every window and door with its dimensions and position, and a list of furniture already standing in the room. Write it in English if you are using an international AI service — that typically gives a more precise answer, because English is the language most AI models are best trained on.
Why "technical" is a different category from an ordinary description
An ordinary design prompt describes what you want — style, mood, function. A technical prompt describes what is there — the actual measurements and positions. The two types of information complement each other, but it is the technical part that stops the AI from suggesting a bed that is 20 cm too long for the room, or a sofa that blocks a door. Without the technical part, any AI suggestion is essentially a guess at an average-sized room that may not match yours at all.
What belongs in a good technical prompt?
- A coordinate system or a clear direction. State which wall faces north, south, east and west — that makes it possible to place furniture relative to daylight and to describe positions unambiguously ("along the north wall" is more precise than "on the left").
- Each wall on its own. Length, and ideally a start and end point if the room is not a simple rectangle. A room with an angle or a sloped wall needs to be described as what it is — assuming a rectangle produces a suggestion that does not fit.
- Windows with dimensions and position. Width, height, which wall, and how far up the window starts (the sill height). That determines whether a piece of furniture can stand under the window, and how much daylight falls where.
- Doors and openings. Width, position and which way they swing — an AI that does not know where the door is will happily suggest furniture that blocks it.
- Existing furniture. Everything staying put, with approximate dimensions, so the AI can work out what fits beside it.
Why is the prompt in English?
Most large AI models are trained on far more English text than any other language, and that goes especially for the kind of structured, technical text a room description is. In practice that means the same information written in English often produces a more precise and less "made up" answer than the same prompt in Danish — the model has simply seen more examples to draw on. It is not a rule without exceptions, and a Danish prompt does work too, but for a technical, measurement-heavy description, English is typically the safe choice. You can still ask for the answer itself in your own language.
An example of the structure
"Room: 3.4 m × 3.9 m, ceiling height 2.5 m. North wall: solid, 3.4 m. East wall: window, width 1.4 m, sill height 0.9 m, positioned 1.0 m from north corner. South wall: door, width 0.825 m, positioned 0.3 m from east corner. West wall: solid, 3.9 m. Existing furniture: wardrobe against west wall, 2.0 m wide, 0.6 m deep, 2.1 m tall."
It looks laborious, but it is exactly this kind of detail that decides whether a suggestion fits or does not. You do not need to match the format exactly — the point is that all the information listed is included, not how it is phrased.
Skewed rooms and sloped walls — say so directly
Not every room is a clean rectangle. If there is a sloped wall under a roof pitch, a corner that has been cut off, or an alcove-shaped part of the room, that needs to go into the prompt as a description of the shape — not just the room's total floor area. An AI that is told "the room is 14 m²" without knowing that a third of it sits under a sloped wall with a low ceiling height can easily suggest placing a tall bookcase exactly where there is not actually standing headroom for it. Describe where the sloped wall starts, its pitch, and its lowest height, whenever it is relevant to the furnishing.
How to check whether the AI has actually understood the prompt
Before you trust a suggestion, it is worth asking the AI to repeat back its understanding of the room: "describe the room's layout as you have understood it, before you suggest furniture." If it answers with a description that does not match what you wrote — wrong wall orientation, a forgotten window, a door in the wrong place — that is a signal that the suggestion which follows is probably wrong too. It is a quick check that can save several rounds of suggestions that never had a chance of fitting.
Should you write this kind of prompt yourself?
The short answer is that you can, but doing it thoroughly is time-consuming: you have to measure every wall, every window and every door, and phrase it all consistently. Most people who try end up skipping a couple of measurements because they feel unnecessarily detailed — which are exactly the measurements that later turn out to be the ones the AI needed. A tool that can generate the prompt from a takeoff you already have saves that part of the work.
What a technical prompt does not solve
- Whether a wall is load-bearing. That is a structural assessment, not a geometric measurement — it requires a professional on site.
- Whether a piece of furniture can physically be carried in through the door. A width on paper is not the same as being able to turn it around in a hallway.
- Whether the measurements are correct. A technical prompt is only as good as the numbers you put into it. If a measurement was guessed rather than measured, the AI inherits that uncertainty without knowing it.
What HouseSense does
HouseSense's technical prompt track automatically builds a long, English prompt from the room's scanned geometry: coordinate system, each wall with its start and end point and compass direction, windows with dimensions and sill height, doors, other openings and existing furniture. You copy the prompt straight into whichever AI service you choose. It is exactly the kind of structure this article has described — built from measurements you never have to type in by hand, because they were already captured during the scan.
In short
- Direction and coordinates first. That makes the rest of the description unambiguous.
- Every wall, every window, every door with dimensions. Not just the room's total area.
- Include existing furniture. Otherwise the AI assumes an empty room.
- Write the technical part in English. Ask for the answer in your own language, if you prefer.