How automatic vectorization works
The drawing is rendered at high resolution, cleaned and separated from its background. Detection identifies straight lines, closed circles, ellipses and text regions and writes entities such as LINE, CIRCLE, ELLIPSE and TEXT.
Why scans create fragments
A printed line has thickness, noise and gaps. Detection may see both sides of a stroke or split it around intersections. Cleanup must merge collinear segments, remove duplicates and ignore isolated marks.
Circles, arcs and curves
Closed circles and oval shapes can often become real CAD entities. Partial arcs, splines and irregular rounded outlines are less certain because only part of the curve is visible.
What happens to text?
OCR can create editable text, but small dimensions and abbreviations can be misread. Verify critical annotations against the source.
What cannot be recovered?
- Original layers and block definitions.
- Properties removed during PDF export.
- Hidden or cropped geometry.
- Exact dimensions without a scale reference.
- The technical meaning of every symbol.
Get a better vectorization result
- Export the PDF directly from the CAD or design application instead of scanning a printout — vector data survives, pixels do not.
- Scan at 300 DPI or higher in grayscale, with the sheet flat and free of shadows and fold lines.
- Include a known dimension or a scale bar so the result can be scaled correctly; see the drawing scale guide.
- Crop away surrounding paperwork so detection focuses on the drawing area itself.
Floor plans and dense drawings
Floor plans combine walls, openings, hatching, dimension lines and text in a small area, which makes them the hardest case for automatic tracing. The floor-plan conversion guide explains how walls, doors and dimensions are recovered and when a redraw gives a cleaner result.
Automatic conversion or manual redraw?
Automatic vectorization is useful for clear linework. Manual redrawing is preferable when continuous geometry and structured layers matter more than speed. Read about scanned drawing conversion.