A generated floor plan does not get traced into a 3D model; it gets used as a reference for one. The pipeline that works is: generate the plan in the Plans phase, save it, attach it to the 3D chat alongside a brief that states the program and the dimensions in numbers, and let the model build the rooms as spaces with partitions and doors between them. The plan governs the arrangement; the brief governs the counts; the model’s own plan view, DXF and IFC4 are what you check against. The example on this page, Mirror Lake House, came out with five rooms totalling 110.4 m² from a brief that asked for five rooms at about 120 m².
This is the pipeline article for people who have a plan they like and want the building behind it. It assumes you have read, or will read, AI Floor Plans: Accuracy, which explains why a generated plan is a diagram of intent rather than a measured drawing. That is the reason the pipeline is shaped the way it is.
Why “convert the plan” is the wrong verb
An AI floor plan is an image. A good one looks like a plan: walls of a consistent thickness, doors that swing into rooms, a kitchen next to a dining room. Measured, it is less reliable. In our own scoring of 72 generated images, countable requirements (room numbers, bedroom counts) were the ones that failed, and duplicated room numbering appeared in seven of nine plans. Areas drawn on plans do not sum to the footprint. Wall thickness drifts by a few pixels from one side of the plan to the other.
Converting such an image into geometry, by vectorising or by asking a model to “extrude the plan”, carries every one of those errors into three dimensions and adds a few. You get a building whose walls are almost parallel and whose rooms are almost the size written on them.
The model-from-words approach avoids this by never treating the image as geometry. The image says what goes where. Numbers come from words. Geometry is written by the model from both, as elements with names.
The pipeline
Step 1: Generate the plan in the Plans phase
Start where you probably already are. Write the brief for the project (program, site, storeys, approximate area), generate plans, branch, choose one. Nuit’s plan generation is per floor, so a two-storey house has a ground plan and a first-floor plan as separate saved images, and interiors generated later read the saved plan for their floor. From Brief to Floor Plan covers this phase in detail.
Save the plan you want to carry forward. Saved images are what the 3D chat can see.
Step 2: Write the 3D brief in numbers
This is the step people skip, and the one that determines the result. The rule from our own demo runs: with references attached, keep the brief short and specific: program, sizes, site. Do not describe form and materials in words; that is what the references are for.
A good brief for a model, with a plan and two exterior images attached:
Single-storey house, 20 × 6 m footprint, about 120 m². From the plan: open living room and kitchen at the east end, main bedroom, second bedroom, bathroom, entrance hall at the west end. Plot 40 × 40 m, lake on the east side. Floor 1.4 m above water level.
What is in there: the count of rooms (five), their names, the footprint, the area, the site, one level. What is not: the roof form, the cladding, the window proportions. Those are in the images.
If the plan image and the brief disagree (the plan shows six rooms, the brief says five), you have asked for two different buildings. Make them agree before you run.
Step 3: Attach the plan and the exterior references
In the 3D view, the saved images of the current phase are on the left. Each has “Use in 3D chat”: click, or drag onto the composer. Up to six images attach, resized to 1,600 px on the long side. Project references (the moodboard) attach the same way.
Attach the plan and one or two exteriors. More references do not improve the model; contradictory ones confuse it.
Step 4: Generate
The empty state shows the estimate (“Generate 3D model · ~N credits”, typically 60 to 150; what a credit buys is on the pricing page) and your balance. Run it. The model writes a script: a parameter block (footprint, wall height, eaves, opening sizes, room dimensions) and a build function that constructs the geometry, tagging each element with its class as it goes.
Partitions and doors are built at this step, not added later. A completion gate checks for rooms that were declared but not enclosed; a model that has named five rooms and built one open box is sent back to build the partitions. This gate exists because early runs produced exactly that, and it looked done.
What you get: walls, partitions, openings with doors and windows related to the walls they cut, slab, roof, structure where the design needs it (columns, beams), and five IfcSpace volumes, each with a name and a computed floor area.
Step 5: Read the model’s own report before judging the picture
The viewport is the least reliable place to check a plan. Use the Plan view (cut at 1.2 m, overall and wall-axis dimensions drawn from the same function the DXF uses), the Parameters panel, which lists every parameter the model declared grouped by IFC category, and the Interiors room list, which is built from the IfcSpace elements with their areas.
For Mirror Lake House, generated from four saved concept images and a two-sentence brief: Living room + open kitchen 56.8 m², Entrance hall 14.1, Main bedroom 13.9, Second bedroom 13.9, Bathroom 11.8. Total 110.4 m² against a brief of “about 120”. The count is right; the total is 8% under, which is worth knowing before a client sees an area schedule.
Step 6: Adjust by words or by hand
Two kinds of edit, two prices.
- Parameter edits are free. “Make the main bedroom 3.6 m wide” hits an existing parameter: it becomes a slider move, and the model is not called. Wall height, footprint, opening widths, eaves, room dimensions where the model declared them. Dragging a wall or an opening in the viewport is the same kind of edit.
- Geometry edits cost 5 to 25 credits. “Add a utility room between the kitchen and the entrance” needs new geometry; the model rewrites the build function, scoped to what the instruction touches, with an estimate before it runs.
Every edit, by either route, is a checkpoint: parameter delta, script hash, preview. Branch from any of them; keep two plan arrangements side by side and compare their room areas rather than their pictures. Branching as a Design Exploration Technique is the images-side version of the same discipline.
Step 7: Send the plan back, or export it
The plan derived from the model can go back to the Plans phase as an image, which is useful when the model has resolved something the generated plan left vague (where the bathroom door actually fits). Or export:
- DXF for AutoCAD: the plan as a sheet with dimensions and room labels, plus four elevations and two sections. What’s Inside an AI-Generated DXF lists the layers and the limits; AutoCAD + AI covers opening it.
- IFC4 for Revit or Archicad: rooms as spaces with areas, partitions as walls, doors as doors hosted in openings. AI to Revit covers the import.
- GLB or OBJ for SketchUp and Blender: the geometry with named groups. SketchUp + AI.
Export is free and unlimited.
Checking the result in BIM
The strongest check is not visual. Open the IFC4 in Revit or Archicad and read what the file declares.
- Count the spaces. Five IfcSpace in the file means five rooms in the model. If the brief said five and the file says four, the model merged two; go back and instruct.
- Read the areas. Each space carries a NetFloorArea quantity. Compare to the brief. A schedule in Revit will list them without any modelling.
- Count the doors against the rooms. Seven IfcDoor for five rooms in Mirror Lake House, named in the file: Entrance, Living hall door, Main bedroom door, Second bedroom door, Bathroom door, Lake sliding doors and the living panorama. Each door is an IfcRelFillsElement in an opening that IfcRelVoidsElement cuts from a wall. A door that is not hosted is a door the model drew next to a wall rather than in it; the gate catches most of these, and the file shows the rest.
- Check the storey. One IfcBuildingStorey. If your project has two floors, the elements are all on one level in the file; this is the current limit of the export and the reason multi-storey projects should be modelled per floor and checked per floor for now.
- Overlay the DXF on your own plan in AutoCAD if there is one: a survey, a site plan, a planning envelope. The DXF is in millimetres by default and the plan’s origin is the model origin; move once, then compare.
If the file passes these, the model is a usable concept model. If it does not, the fix is in the studio, by instruction or by slider, not in Revit.
What the plan image does and does not do
To be precise about the reference, because this is where expectations go wrong:
The plan image sets the room arrangement, the adjacency, the proportion of the footprint, roughly where the entrance and main openings are, and the general idea of circulation.
The plan image does not set dimensions (the brief does), room counts reliably (the brief does), wall thicknesses (the model’s parameters do), or door positions exactly (the model places doors where partitions allow). It is not measured, scaled or vectorised. A hand sketch or a scan of an existing plan works the same way, as a reference. There is no DWG or PDF import; a plan in those formats should be exported as an image first.
This is the same stance as the rest of the product: images are project memory, not input files. It keeps the pipeline honest about what is being read.
Where it fits, and where it does not
Fits: early residential and small commercial projects where the plan is the design argument and the client wants to see the building around it; competition and feasibility stages where five arrangements need comparing by area and not by picture; any office that would otherwise remodel a chosen plan in SketchUp or Revit from the image.
Does not fit: renovation of a surveyed building (start from the survey in your CAD tool); anything needing multi-storey BIM export today; projects past schematic design, where the model’s level of development is below what the work requires. When NOT to Use AI in Architectural Design is the longer list.
The 3D mode is open to every account from the Images | 3D switch in the studio, same as the Plans phase and the rest of the images side, with 300 free credits (12 images) on signup. Download the Mirror Lake House files first and check them against the numbers above; that is the point of publishing them.
Frequently Asked Questions
Can an AI floor plan be converted directly into a 3D model?
Not by tracing. Image-to-geometry on AI plans carries drifting wall thickness, misplaced doors and non-summing areas into 3D. Use the plan as a reference and generate the model from a brief with numbers.
What does the 3D model read from a floor plan image?
Arrangement: which rooms sit where, how they connect, proportion, where the entrance and main openings fall. Not measurements. Counts, areas and dimensions come from the brief.
Are the rooms in the model real rooms?
Yes. IfcSpace with name and floor area, enclosed by walls and partitions built at generation, with doors as openings. Interiors enters a room through its door. In IFC4 they arrive as rooms or spaces with areas.
What if the model builds rooms without partitions?
A completion check catches rooms declared but not enclosed, and the run continues until the partitions exist.
How do I check the model against the plan I started from?
Plan view in the studio (cut at 1.2 m, dimensions from the same function as the DXF); DXF overlay in AutoCAD; IFC4 element counts and room areas, which the examples page prints for the published models.
Can I go the other way and get a plan out of the model?
Yes. The plan view can be sent back to the Plans phase as an image, and the DXF writes it as a dimensioned sheet with room labels, consistent with the elevations and sections by construction.
Does this work for multi-storey plans?
Partly. Plans are per floor, but IFC and DXF export currently write one storey, with the DXF plan cut at a level you choose.
Try Nuit free — 300 credits (12 images), no card required. Generate the plan, save it, and when 3D access is enabled, attach it to the model brief. Start your project →