Free browser PDF tool
Annotate PDF online — free browser markup, no upload
Mark up PDFs with rectangles, arrows, and text — right in your browser. The full A&E toolkit (clouds, callouts, calibrated measurements, symbol libraries, BCF round-trip) lives in LocusBIM Desktop. No upload, no account.
Annotate a PDF
◐ Runs locally in your browserBuilt for engineering and architectural drawing review
Most "annotate PDF" tools are built for office documents — a yellow highlight, a sticky note, a pencil-mark scribble. LocusBIM is built for the actual review work A&E firms do: revision clouds, RFI callouts, professional seals, measured take-offs, discipline symbol libraries, and BCF export for handing issues to your structural consultant. If you've used Bluebeam Revu, LocusBIM will feel familiar — but it runs locally on Windows, macOS, and Linux, with no per-seat subscription.
What you can mark up with
Revision clouds + callouts. The two markups every review uses. Cloudbar lets you draw irregular clouds with the bump sizes that match your firm's standard. Callouts auto-leader from the cloud to your annotation text.
Measurement tools. Linear, area, polylength, radius, diameter, angle, and count. All calibratable to the drawing's scale — set the scale once and every subsequent measurement reports in real-world units (m, ft, yd).
Drawing tools. Rectangle, ellipse, polygon, line, arrow, freehand, double-line, leader, spline, polyline — with the line styles, weights, end caps, and fill patterns you expect from a drafting tool. Layer support for organising markup by reviewer or discipline.
Symbol libraries. 200+ discipline symbols across electrical, mechanical (HVAC, plumbing), fire/life-safety, structural, civil, architectural, and laboratory categories. Drag, place, resize.
Stamps + signatures. Approved, Rejected, As-Built, For Construction stamps. Custom image stamps (your professional seal). Handwritten signatures. See Sign PDF for the full signing toolset.
Text + form fields. Typewriter text directly on the page. Highlight / strikethrough on existing PDF text. Form fields (text input, checkbox, signature line) for fillable PDFs.
Annotation workflow for drawing review
A typical A&E review cycle with LocusBIM looks like this:
- Receive the structural drawing set as a PDF.
- Open in LocusBIM, calibrate scale once.
- Use revision clouds + numbered callouts for review comments.
- Use measure tools for quantity / dimension verification.
- For each issue: create an Issue from the markup (right-click → Create Issue). The issue carries the screenshot, the markup geometry, the sheet reference, and your description.
- Export issues to BCF (Industry Foundation Classes Building Collaboration Format). The structural consultant imports BCF into Revit / Solibri / Navisworks and sees every issue tied to its location.
- When they reply with revisions, import their BCF back to round- trip the conversation.
How it compares to cloud PDF annotators
Frequently asked questions
What kinds of annotations can I add?
Everything you'd find in Bluebeam: rectangles, ellipses, lines, arrows, callouts, clouds, polylines, polygons, freehand drawing, text (highlight, strikethrough, typewriter), measurement (linear, area, radius, angle, count), stamps, signatures, and a library of discipline symbols (electrical, mechanical, fire/life-safety, structural). All markup is vector-based and saves into a separate annotation layer — the original PDF stays untouched.
Are my markups saved into the PDF file?
Two ways. By default, markups live in LocusBIM's local SQLite database alongside the PDF — you can review, edit, and delete them across sessions without modifying the source PDF. When you're ready to share the marked-up drawing, choose Flatten to bake the annotations into a copy of the PDF, or Export to BCF for an industry-standard issue file the structural consultant can import into Solibri / Revit / Navisworks.
Does LocusBIM read existing PDF annotations?
Yes. When you open a PDF that already has annotations from Acrobat, Bluebeam, or another tool, LocusBIM imports them into its own markup layer so you can edit, comment on, or remove them. Round-trip to Bluebeam: open → annotate → save back → reopen in Bluebeam, see your changes.
Can I add measurements with real-world scale?
Yes. Use Measure → Calibrate to set the scale (e.g. 1:50, 1:100). After calibration, linear, area, polylength, radius, and angle measurements show real-world values (mm, cm, m, in, ft, yd). Per-page calibration is supported — different sheets in a set can have different scales.
Will my markups be visible to someone who opens the PDF in Adobe Reader?
If you flatten the markups into the PDF (one menu click before sharing), yes — they're permanently baked into the page content and visible in every PDF reader. If you don't flatten and share the .lbim sidecar instead, only other LocusBIM users will see the markup layer. For external review, flatten before sending.
Does this work for drawings, or only for office documents?
LocusBIM is built specifically for engineering and architectural drawings. The annotation tools (clouds for revisions, callouts for RFI bubbles, measure tools for take-offs, BIM-linked symbols) match A&E review workflows. You can mark up office PDFs too, but the tooling is biased toward drawing review.
Are annotations uploaded anywhere?
No. LocusBIM runs entirely on your machine. Annotations are stored in a local SQLite database in your user data directory. They're never uploaded unless you explicitly use the LocusSync collaboration feature or generate a Share Link for an issue.
Beyond annotation
The same desktop app handles splitting, combining, and signing — plus 3D BIM coordination, BCF round-trip, LocusSync collaboration, and CAD plugins for AutoCAD, MicroStation, and Revit. See pricing for the full feature breakdown.