If you can get the DWG, start there. Illustrator opens DWG and DXF files and keeps the drawing’s layers apart, unless you tick Merge Layers in its import dialog. The same dialog lets you import at original size and scale lineweights. Adobe’s help page lists AutoCAD 2.5 through 2007 as the formats Illustrator reads, so ask the sender to save a 2007 DXF.
Often all you get is the PDF. The architect has moved on, the file came through a client, or the office won’t release its DWGs. This is what happens to that PDF in Illustrator, and how to get the layers back.
What Illustrator does with a CAD PDF
We took one sheet from a public set of construction drawings: a 42 x 30 inch floor plan with 24,635 paths spread over 43 CAD layers. A-GLAZ-CWMG alone holds 11,517 paths, Text holds 4,797, P-SANR-FIXT holds 2,039, and Hatching holds 532 short strokes.
Illustrator 2026 opened it as one layer with 27,020 paths inside 492 groups. The walls, the plumbing fixtures, the hatching and the title block all sat on that layer together. Selecting “all the walls” meant hunting through the paths by hand.
The lettering came in as lines, not type. The Text layer on this sheet is 4,797 paths, and Illustrator created no text frames. Check your own file before you plan to retype anything.
Check the PDF before anything else
Open it in Acrobat or Acrobat Reader and show the Layers panel: View > Show/Hide > Side Panels > Layers. Switch a few layers off and watch the drawing.
Look at every sheet. Our drawing set has 44 sheets and defines 190 layers, yet only 4 sheets have any artwork assigned to those layers. On the other 40, switching a layer off changes nothing. Those sheets carry no layer information in the drawing itself, and no tool can split them.
If a sheet has no working layers, ask the sender to plot it again with Include layer information ticked in the PDF options, and to switch on and thaw every layer you need first. It is one checkbox in their plot settings.
Getting the layers into Illustrator
PDFLayerExtract reads each layer from the PDF and writes it to its own file, at the original sheet size and position, together with an Illustrator script that stacks them into one document. The same split on a packaging label with spot colors is shown in Split PDF layers into separate PDF files.
On our sheet:
- The free check listed 44 layer items: the 43 layers with linework and one layer that holds 4 images.
- All 19,106 stroked paths kept their original line weight: 0.36, 0.48, 0.84, 1.32, 1.92 and 2.16 pt on this sheet.
- We stacked all the layer files back together and compared them with the original sheet: no line missing, no line added.
Now A-WALL, A-DOOR and the plumbing sit on their own layers. You can hide the dimensions, restyle the walls or delete the ductwork for a presentation board.
Acrobat’s Layers panel shows all 190 layers of the drawing set, some of them several times. The check lists only what this sheet actually draws. It skips layers with nothing on them, such as Levels, References and the sheet border blocks, and joins six layers that the PDF splits in two, among them A-WALL, I-WALL and Existing. Every layer name appears once.
Things specific to CAD PDFs
Hatches stay as they were plotted. The Hatching layer on our sheet is 532 separate strokes, and after extraction it is still 532 strokes. Select the layer and restyle them together, or replace them with an Illustrator pattern.
Scale stays as plotted. Every layer keeps the sheet’s page size and position, so a 42 x 30 inch sheet stays 42 x 30 inches and the layers line up. Scale the finished document, and Illustrator will scale the line weights with it if you have Scale Strokes & Effects switched on.
A layer that was frozen or switched off in the drawing when it was plotted does not print into the PDF, so it can’t come out again. Ask for a new plot with that layer on.
What this does not do
It doesn’t turn the PDF back into a DWG. Blocks, xrefs, layer states and dimensions as objects stay in AutoCAD, because the PDF never carried them. You get the plotted drawing split by layer, at the right size and position, in a form Illustrator can edit.
The check is free and shows every layer it finds before you pay.