Pen AI: Pen Digitizer

Capture how a sketch is drawn, one pen movement at a time. Pen AI uses your iPhone or iPad camera to follow an ordinary physical pen. Connected strokes appear over the camera view while the app records coordinates and timestamps for replay and export. SET UP YOUR PEN Photograph your uncapped pen on a plain table and confirm its outline and writing end. The saved reference helps object detection find your pen again. SCAN AND ANCHOR YOUR PAGE Choose A4, Letter or A5 to match your paper, tap Scan page, and show all four corners. Wait for the page to lock before writing. A rectangular grid keeps the drawing aligned as the phone moves and preserves page proportions and margins in saved sketches. Keep the paper flat and stationary; rescan if it moves. FOLLOW YOUR WRITING Keep the nib and shaft visible in good light. Tracing starts with a usable tip. Pause and resume when needed. Use Ink on / Pen lifted between letters, lines and shapes to separate strokes. A held cursor keeps its last position while tracking recovers. REVIEW MISSED MOVEMENT With frame retention enabled, review captured images to recover visually supported tip positions. Check the recovered sketch and undo frame review if necessary. Recovery is an estimate and cannot reconstruct every hidden movement. You can also save without frame review. REPLAY AND EXPORT Save drawings in Sketchbook, replay strokes, scrub through time and inspect recorded movement. Export PNG images, SVG sketches, CSV coordinates or a full JSON recording. Try the clearly labeled synthetic demo to explore replay and exports before live capture. ON YOUR DEVICE Camera analysis, pen matching and frame review run locally. Temporary review images are deleted after saving, clearing a capture or the next app launch. Saved sketches and pen references stay on your device. You choose what to export. No app account is required. Live tracking requires an ARKit-capable device and camera permission. Results depend on lighting, pen visibility, motion and calibration. Pen AI captures strokes; it does not convert handwriting to typed text or measure pen pressure. Recorded drawing-space XYZ coordinates are estimates on a calibrated plane. Use the ink control between strokes because paper contact is not reliably detected.