Frequently asked questions
Technical answers on formats, CAD compatibility, metric accuracy, confidentiality and professional use of the drawings.
Which image formats can I upload?
JPG, PNG and WebP up to 40 MB per file, from desktop or straight from a smartphone camera. These are the three formats verified end-to-end across the whole flow, from cropping to generation: other formats are rejected at upload, so convert them to JPG or PNG first.
How long does processing a single image take?
In almost every case the wait is between one and two minutes, averaging around ninety seconds. The main factor is the effective resolution of the file: a large photoplan or an elevation with many mouldings takes longer than a photograph of a single element. Processing runs server-side, so you can stay on the page and follow progress through to the vector preview.
What file formats can I download?
Every conversion produces an archive containing the vector drawing in SVG and DXF. The SVG is suited to layout, publishing and graphic editing; the DXF is the standard exchange format for CAD environments and stores the geometry as vector entities (polylines and segments), not as an embedded image. Alongside the vectors, the raster line-art generated in the first pass is also kept as a visual reference.
Which CAD and vector software are the files compatible with?
The DXF is generated in a version compatible with AutoCAD 2013 (R2013) and every later release, while also being readable by earlier versions from R2010 onwards. It has been verified with AutoCAD, BricsCAD, Rhino and QGIS. The SVG opens without any conversion in Adobe Illustrator, Inkscape, Affinity Designer and any browser. For fieldwork, the DXF can be imported into QGIS and carried over to QField.
How does calibration to real scale in millimetres work?
Once the vector drawing is generated, the preview lets you pick two points on the drawing, with automatic snapping to line vertices to increase precision. You then enter the real-world distance between those two points in millimetres, centimetres or metres. The system calculates the scale factor and asks the vectorisation engine to regenerate the drawing already scaled: the DXF is never edited after download, which preserves its structural integrity.
Do I need a professional photogrammetric survey, or is a single smartphone photo enough?
A single photo taken with a recent smartphone is enough to obtain a usable drawing, provided the shot is as frontal as possible, evenly lit and free of blur. For output intended for rigorous metric use — construction drawings, quantity take-offs, expert reports — it is best to start from a rectified photoplan or an orthophoto produced with photogrammetric software, since perspective correction directly affects the dimensional accuracy of the result.
What happens if the photo has perspective distortion or isn't orthorectified?
The vector geometry is still extracted, but it inherits the distortion present in the source image: measurements will only be correct along the direction used for calibration and progressively less reliable elsewhere. If the photo was taken from a strongly angled viewpoint, it is best to rectify it before upload using a four-point rectification procedure, available in most photogrammetry and photo-editing software.
Does the tool work on decorated surfaces, frescoes and stucco, or only on architecture?
It works on both. Geometry extraction is based on tonal and material transitions, so it produces valid results on decorative apparatus, frescoed surfaces, stucco and bas-relief, as well as on architectural elevations. On moulded elements — stucco, cornices, mouldings — a shot taken in raking light noticeably sharpens the definition of the profiles, because it accentuates the arrises and changes of plane.
How long are uploaded photos and generated files kept?
Each conversion — the uploaded photo, the intermediate line-art and the archive with SVG and DXF — is kept for 5 days after generation. Within that window you can reopen it from the "Conversion history" section of your account, compare photo and drawing with the slider, rescale the vector drawing, reset the spatial coordinates and download the SVG and DXF again. After the 5 days, the files are permanently deleted from our storage through an automated process: the conversion remains visible in the history but marked as "expired", with no way to recover it. We therefore recommend saving downloaded files locally. Automatic deletion limits the amount of data retained, reducing exposure of confidential material and storage use.
Do my data and photographs remain confidential?
Yes. Uploaded images and generated files are stored in private buckets with no public address, with access rules enforced at the database level: each account can only read its own folder, so no other user on the platform can list or download your files. Preview and download happen through temporary signed links tied to your session, which expire automatically. Materials are never made public, are not indexed by search engines, and are not used to train models or published as examples. All files are automatically deleted 5 days after conversion, and you can request early deletion at any time: a requirement designed for those working on behalf of public bodies and heritage authorities, where confidentiality of documentation is binding.
Can anyone at CVCAD see my images?
We prefer to be explicit about technical limits. To extract geometry, the photo must be readable by the computer-vision engine, so during processing the file is accessible to the service's automated processes and, technically, to staff with infrastructure administration privileges, who access it only for maintenance or to respond to a support request from you. We do not use zero-knowledge encryption, because that would make server-side processing impossible: no cloud image-vectorisation service can claim otherwise. What we do guarantee is that no other user can access your files, that nothing is public or indexed, that materials are never used to train models or shown as examples, and that everything is automatically deleted after 5 days. For specific contractual needs — data processing agreements, reduced retention, processing without storage — dedicated arrangements can be discussed.
Can I use the generated drawings in a professional assignment or an expert report?
Yes. The drawings produced are your property and can be used without restriction in professional assignments, project drawings, expert reports and public contracts, including commercial use. CVCAD claims no rights over the output. As with any technical drawing, the professional remains responsible for the metric verification and validation of the drawing before it is used in documents that produce legal effects.
Do I need to create an account to try the tool?
Yes, registration is required to link conversions to your credit balance and to ensure the confidentiality of uploaded files. On sign-up you receive 1 free trial conversion, with no payment details required. You can register with email and password, with Google, or with Apple.
Is an API available for external integrations?
A programmatic interface for integration into existing workflows — practice management software, photogrammetric pipelines, document systems of heritage authorities — is available on request for professional and institutional accounts. Get in touch describing the expected volume and use case so we can assess activation.
What's the difference between CVCAD and a generic auto-tracing tool?
A generic auto-tracing tool, like the automatic tracing functions in graphics software, works on colour thresholds and produces closed fills that follow the image's colour variations, generating thousands of redundant, noisy polygons. CVCAD uses a computer-vision model trained to recognise built geometry and decorative apparatus: it interprets edges, discontinuities and contact lines, returning continuous, coherent linework suited to CAD environments. It also handles metric calibration, which no generic tracing tool provides: the file comes out at real scale in millimetres.
Try CVCAD on your next survey
Sign up and get 1 free conversion: upload a photo and download a DXF already in real millimetre scale.