Convert a Floor Plan Image to DXF
From a paper blueprint, scan or photo to a millimetre-accurate CAD file
A lot of buildings only exist on paper: an old blueprint in a binder, a landlord's scanned PDF, a photo of the fire-escape plan by the lift. When the next step needs a real CAD file — a DXF or DWG for a wireless site survey, a facilities system, or an architect — a picture isn't enough. Gridsnap turns the picture into the CAD file: import it as an underlay, set the scale against one known distance, trace the walls, and export a clean DXF at true size.
A scanned plan mid-trace: the left half is already CAD geometry; the right half is still paper.
From Blueprint to DXF in Four Steps
Import the blueprint
Drop in the image you have — a scan of a paper blueprint, a photo taken on site, a PNG, or a screenshot of a PDF page. It appears as a faded underlay beneath the drawing grid.
Calibrate the scale
Click two points whose real distance you know — a printed dimension, a doorway, a wall you've measured — and type it. From then on the model is in true millimetres, which is exactly what the DXF will carry.
Trace the walls and openings
Draw over the underlay. The snap engine keeps walls straight and corners exact even when the scan is skewed or the paper was creased — you trace the building, not the pencil line. Doors and windows snap onto the walls.
Export the DXF
One click in the Export dialog produces a clean vector DXF: millimetre-accurate model space, with walls, openings, text and dimensions on their own layers. Free, no watermark, no account.
Built for Wireless Surveys and Facilities Work
This workflow gets the most use from network and facilities engineers. Wi-Fi survey tools like Ekahau and Hamina will accept a plain image of a floor, but the survey is only as good as the map under it: a CAD file carries real wall geometry at true scale, so the prediction model works with actual walls instead of pixels. Platforms for indoor wayfinding and asset tracking often won't take an image at all — they require CAD.
The trace workflow covers both: ten to thirty minutes with the blueprint gets you a millimetre-accurate DXF, and where a platform insists on DWG, the free ODA File Converter turns the DXF into a DWG in one lossless step. As a bonus, the traced model isn't a one-off export — it stays editable in Gridsnap, so the next survey or refit starts from the model, not from paper again.
Why the DXF Comes Out Clean
Gridsnap isn't a drawing app exporting a picture — it's a small CAD engine. Everything you trace is stored in integer millimetres, walls are solved into exact mitered geometry, and the DXF is written from that same geometry: real model space at 1:1, R12 ASCII for maximum compatibility, with walls, openings, dimensions, areas, furniture and text on separate layers you can toggle in the receiving tool. The same model also exports a true-vector PDF at printed scale, if paper is where it needs to go back to.
Common Questions
Is the conversion automatic?
No — Gridsnap doesn't auto-vectorize the image. You trace the plan over the calibrated underlay, and the snap engine does the precision work: walls come out straight, corners exact, dimensions real. A typical floor takes on the order of 10–30 minutes, and the result is a clean CAD model rather than a best-guess auto-trace you'd spend the same time correcting.
What kind of DXF does Gridsnap export?
An AutoCAD R12 ASCII DXF — the most widely compatible flavor — drawn in model space at real size, in millimetres, with separate layers for walls, openings, dimensions, areas, furniture and text. It opens in AutoCAD, LibreCAD, QCAD and anything else that reads DXF.
My tool requires DWG, not DXF. What do I do?
Convert the DXF to DWG with the free ODA File Converter (from the Open Design Alliance) — it's a one-step, lossless conversion that runs on Windows, Mac and Linux. Export the DXF from Gridsnap, run it through the converter, and load the DWG into your tool.
Does this work for Wi-Fi site surveys (Ekahau, Hamina)?
Yes — this workflow exists for exactly that job. Survey tools accept plain images, but a CAD file carries real wall geometry at true scale, which makes the survey model much more accurate. Trace the blueprint once, export the DXF, and import it into your survey tool; if the tool wants DWG, convert with the free ODA File Converter first.
I only have a PDF. Can I convert it?
Take a screenshot of the PDF page and import that as the underlay. A PDF floor plan is just a picture of a plan, so the screenshot loses nothing — and after calibration the traced model is at true scale regardless of the screenshot's resolution.
Is the DXF export free?
Yes. Importing an underlay, calibrating, tracing and exporting — DXF, vector PDF and PNG — are all free, with no watermarks and no account required.
Tracing a plan to edit it rather than convert it? See editing an existing floor plan — same workflow, aimed at renovations. New to plan drawings? The floor plan symbols guide explains what everything on the blueprint means.
Got a blueprint to convert?
Import it, calibrate, trace — and export a millimetre-accurate DXF. Free, no account needed.
Open Gridsnap Editor