How to get PDF linework back into CAD as DXF

When you need PDF linework in CAD

• Redlines that should become design changes, without someone redrawing them by hand.
• Existing conditions or a consultant's sheet that you only have as a PDF.
• Alternatives sketched on a plan during review that the CAD team needs to pick up.

First, check whether the PDF is vector or a scan

A PDF exported from CAD keeps its linework as vectors. A scanned sheet is an image. Zoom far into a line: vectors stay crisp at any zoom, while a scan turns blurry and pixelated.

Vellum works best with vector PDFs. Scanned PDFs still open and can be marked up, but extracting geometry and snapping to the drawing rely on vector content.

Step by step in Vellum

1. 1

   Upload the PDF

   Drag it onto the upload area. During import, Vellum analyzes the document's vector content so its geometry can be snapped to and extracted.

2. 2

   Isolate what you need

   If the PDF carries CAD layers, open the Layers pane to hide or fade the ones you don't need, such as the survey.

3. 3

   Extract the geometry

   Press E for the Object extractor and click or marquee the linework you want: Vellum turns it into editable entities. Or press X for Vector screenshot and drag a box to capture a whole region as vector geometry.

4. 4

   Clean up and draft

   Edit the extracted lines like anything you drew: offset, trim, extend, mirror, and fillet, with typed lengths and angles.

5. 5

   Export DXF

   Export the drawing only, your markups only, or both, and apply a preset so styles and layers map consistently.

Tips for a clean handoff

• Extract only what the CAD user needs. A focused DXF is easier to reference than the whole sheet.
• Use the same export preset every time, so styles and layers map the same way in each file you send.
• Send the flattened or editable PDF alongside the DXF, so reviewers who don't use CAD can see the same changes.