Short answer
Yes, to a useful degree. SteelFlo reads scanned and image-based PDFs as well as CAD-exported ones, boxes the member callouts it finds, and flags what it is unsure about for your review. Quality depends on the scan: sharp, high-resolution sheets read well, while faded, skewed or handwritten ones will need more manual checking.
Vector versus scanned PDFs
A vector PDF carries real, selectable text, so software can read the labels directly. A scanned PDF is a picture of a drawing, so the labels have to be read from the image. The five-second test: try to select text in the PDF. If you can highlight a member size, it is vector. If nothing highlights, it is a scan.
Half the sets a small fabricator receives are scans: renovation jobs from paper archives, sets printed and re-scanned to add stamps, older originals. If your process only works on CAD exports, you are counting those by hand.
What affects the result
- Resolution. Larger sheets scanned at low resolution lose small text.
- Skew and noise. Tilted pages, stains and photocopy artifacts hurt.
- Handwriting. Hand-lettered callouts vary too much to rely on.
- Compression. Heavily compressed scans blur thin lines.
- Sheet size. A 36 by 24 inch sheet reduced to letter size is harder than the full-size scan.
If you can rescan, scan at a higher resolution, flat, at full size. If you cannot, accept that more of the review will be manual.
How should you review a scanned takeoff?
Review more of it. On a clean vector set you might sample trusted detections and focus on flags. On a scan, check every page, compare totals against any schedule or member list on the set, and add any missed member by hand. Treat the AI as getting you most of the way and your own review as the finishing step.
The 95 to 99 percent accuracy claim applies to AI plus human review, and scans are where review matters most.
How do you tell if your PDF is a scan?
Open it and try to select a member size with the text cursor. Zoom in: vector text stays sharp at any zoom, scans get blurry or pixelated. File size is another hint, because a 40-sheet scan is often much larger than the same set exported from CAD. For more, see Steel takeoff from scanned drawings and Can AI read steel drawings?.
How can you get better scans?
- Scan at 300 dpi or higher, and higher for full-size sheets with small text.
- Keep sheets flat and square to the scanner. Skew costs readability.
- Scan in grayscale or color rather than heavily thresholded black and white.
- Scan at full size if you can, not reduced.
- Do not apply heavy compression. File size is cheaper than a missed member.
- Ask the GC or architect for the CAD-exported PDF instead. It is nearly always better.
If the original PDF came from CAD and was printed and re-scanned to add a stamp, ask for the clean one.
What should you do when the scan is bad?
Tell the GC. A poor scan is a reason to ask for a better set, and the request is on the record if a dispute comes up later. If a set cannot be improved, take off what the tool and your eyes can read, list the unreadable areas as exclusions or allowances, and mention them in the bid. Never fill in a guess silently.
Does scanned always mean worse?
No. A clean, high-resolution scan of a well-drafted sheet can be nearly as readable as a CAD export. The bigger issue is the drawing itself: old hand-lettered sheets are hard for anyone to read. Judge by the sheet, not the file type. Try a page and look at what is found.
Stop counting steel by hand.
Upload your drawing set and SteelFlo puts a box on every steel label it finds, on every page. You verify the boxes and export a bill of materials.