Compare Documents marks differences with orange cloud markups and is built for scanned or rasterized PDFs; Overlay Pages merges vector PDFs and colors each file's content separately. Neither tool, per Bluebeam's own support pages, reads a door schedule, a specification section, or another discipline's sheet — they compare drawing geometry, not the documents that geometry has to agree with.
Two tools, and Bluebeam says they are not interchangeable
Per Bluebeam's own comparison of the two features (accessed 2026-09-14), Compare Documents "highlights differences between two PDFs using cloud markups" and is meant for scanned, rasterized PDFs; it can also compare more than two PDFs at once, with results listed in the Markups List. Overlay Pages instead merges the content of multiple files and displays each file's edits in a separate color, and needs clean vector PDFs rather than scans to work well.
| Feature | Built for | How a change shows |
|---|---|---|
| Compare Documents | Scanned or rasterized PDFs; more than two files at once | Orange cloud markups on a new PDF, listed in the Markups List |
| Overlay Pages | Vector PDFs, not scans; whole pages or selected regions | Merged pages with each file’s content in its own color |
| Smart Overlay (Revu Max) | Vector sheet sets across a whole issue | A match score by sheet and discipline across the set |
Bluebeam's page states plainly that a workflow combining both tools on scanned PDFs "won't produce the desired result" — the two features are matched to different file conditions, not stacked for a better answer.
What the cloud markups do not tell you
Both tools read the drawing sheet as a page: shapes, lines, and text position. Neither reads a schedule row, a diagram callout, or a specification section as a linked piece of data.
In Groundbook's published mixed-use review, the equipment-consistency finding is a case where the plan symbol for a piece of equipment did not move between issues, so an overlay would have shown a clean, unchanged sheet at that location. The disagreement was in the equipment's duty, material, and operating sequence across the plan, the schedule, the diagram, and the specification — four documents an overlay of two drawing PDFs never opens.
Where the rest of the comparison happens
Use Compare Documents or Overlay Pages for what Bluebeam built them to do: see what moved on the sheet and cloud it for a response. For the dependent schedule, specification, or other discipline's drawing, use a review scoped to that relationship — cross-discipline coordination or drawings vs. specifications — or Groundbook's drawing version comparison workflow, available to beta users on request, which is built to trace a changed requirement into what depends on it.
See how six other tools' compare features stack up against the same question.
If your firm also uses Acrobat
Many teams keep Bluebeam for markup and Acrobat on hand for a quick version diff on a spec or a memo. Acrobat's own Compare Files tool works differently from either Bluebeam feature — see how Acrobat's compare tool works, and what it does not check.