Swing dossier · No. 001 ·
The Zac File
Two swings. Every frame tracked, every joint measured in 2D and 3D, then read by an AI coach that has looked at more golf swings than anyone alive.
01 · Film room
Every frame, tracked
Teal skeleton, yellow spine axis, grey ghost = where he started. The hand trail heats from green to red as speed climbs.
02 · 360 orbit
Walk all the way around his swing
True 3D skeleton reconstructed from the phone video. Drag to orbit, scrub to move through the swing. Gold = hips, teal = shoulders: the gap between them is the coil.
03 · Telemetry
The numbers under the swing
Hand speed through the swing
Lead/trail hand midpoint, m/s, scaled to a 6'0" frame. Bands mark each phase.
Tempo
Backswing time vs downswing time. Tour players cluster near 3 : 1 regardless of swing speed.
Measured, not guessed
| Metric | Clip | Zac | Tour window | Read |
|---|
04 · Report card
Graded on every facet
OVERALL
Uncharted
Five facets nobody has graded before
05 · The prescription
Three fixes, ranked by strokes saved
Four-week plan
What he already owns
Archetype
06 · The handicap read
Estimated handicap
07 · The roast
The roast
Delivered with love. Share responsibly.
08 · The lab
Your swing. Same treatment.
Drop in a phone video of one swing (face-on or down the line, whole body in frame, under 20 seconds). Tracking runs on your device; the video never leaves it.
Method
How this was built
Tracking. YOLO11-x pose (17 joints) on every frame, golfer isolated from onlookers, then MediaPipe Heavy for a metric 3D skeleton cropped to the golfer. Swing phases are found from hand speed and height, not by hand.
Measurement. Angles and distances come straight from the joints. Distances are scaled to an assumed 6'0" height; speeds are hand speeds, not clubhead speeds. The face-on driver clip is 24 fps, so its timing is ±40 ms.
Judgement. An AI coach (Grok) looked at every key frame raw and tracked, with the numbers beside it, and was told to reconcile the two and say where 2D tracking gets fooled by camera angle. Read the grades as a sharp coach's opinion, not a launch monitor.