Or use Calibrate (Measure tab) to click two points along a known dimension.
Enter the real length of the line you drew. Examples: 25, 12'6", 12' 6, 30.5
Pick the open PDFs to merge. Pages go in tab order. The combined file downloads and opens as a new tab.
Markups are not carried into the merged file; export a tab with File ▸ PDF first if you want them flattened in.
Enter the real-world coordinates of the plan point you just clicked, or stand on that spot and capture them.
Enter your passcode
Open PDF plan sets, DWG or DXF drawings, and 3D models (GLB/GLTF, OBJ, STL). DWG opens directly (a 9.5 MB reader downloads the first time and is cached by the browser). CAD drawings open centered and fit to the screen, with scale set automatically from drawing units. Markups auto-save on this device per file; use File ▸ Save Project to keep a portable copy.
Takeoff: set the scale (status bar ▸ Scale, or Measure ▸ Calibrate), then use Length, Polylength, Area, Perimeter, Count. Set a Subject (e.g. 2" PVC Conduit) in Properties so totals group in the Markups List Summary. Save configured tools in the Tool Chest for one-click reuse.
Field photos (as-builts): pick Field ▸ Field Photo and click the plan where the condition is; your camera or photo picker opens and the picture pins to that spot. Move or resize it with Select; double-click it to view full size or delete. Photos ride along in Save Project and the exported PDF.
GPS layout: Field ▸ Georeference ties the plan to real coordinates: click two known points far apart and enter (or stand on them and capture) their latitude / longitude. Then GPS Point pins items such as a pole base with a name and grade elevation; coordinates fill in automatically, or capture a live fix at the spot. Live GPS shows your position as a blue dot; select a pin to read distance and bearing to it. Export / Import GeoJSON exchanges points with survey and GIS tools. The CSV and Excel exports include a GPS points table.
Tabs & combining: open several files at once (multi-select in the Open dialog, or drop several); each gets a tab with its own markups, scales and view. File ▸ Combine PDFs merges open PDFs into one file. File ▸ Lock sets an optional passcode for this device.
Tool Chest sets: My Tools (keys 1–8), Architect / Contractor / Engineer review sets, General Measurements, and Design and Construction symbols (section, elevation, keynote, door tag, revision callout and more; numbered symbols count up automatically).
Touch: one finger draws / pans (Pan or Select tool on empty space), two fingers pinch-zoom and pan. Double-tap or ✓ Finish completes multi-point tools.