Load a motion capture trial

Drop a Qualisys .tsv, Xsens .mvnx, .c3d, or .bvh file here, or choose a file. A teaching and quick-look tool, not a research pipeline. Everything runs in this browser; nothing is uploaded.

Example: full-body optical gait (200 Hz), from Warmerdam et al. (2022), Data 7(10):136, doi:10.3390/data7100136 · CC-BY 4.0. Includes real dropouts — try the gap-fill & merge tools. Same participant, same walk, wearing IMUs — open the inertial signals in the IMU tool.

Example: full-body Xsens MVN capture (inertial mocap, 23 segments, 60 Hz) — a football dribble · anonymised .mvnx, read natively (no conversion). Shows how IMU-based segment data looks alongside the optical trial.

Unnamed markers are fine. Click any marker to label it by hand.
Measure joint/segment angles, marker-to-marker distances, or a projected polygon area — pick points from a dropdown or by clicking.
Optionally smooth measurements with a zero-lag Butterworth filter, then export the labelled TSV, a label map, or the measurement time series as CSV.

Reading file

Marker presence

Frame — / — Speed 1.0×

Space=play · ←→=step · Shift+←→=±10 · V=select · B=bone · D=distance · E=event · C=virtual · X=export · L=plumb · A=3-pt angle · G=angle-to-plane · P=polygon · Shift-drag=pan · Esc=cancel

Controls

Display

Names in 3D Unlabelled Show gaps

Marker size 1.0×

Centre on marker

Session

Save your labels, measurements and skeleton to a file, then reload them onto the same trial later. Everything stays in this browser — nothing is uploaded.

Export

Build exactly the columns you want — markers, virtual markers and measurement outputs — with an optional 0–100% time-normalise.

Re-export (labels & relabelling)

For reimport / relabelling, not analysis.

Send data out

Sends the selected markers' X/Y/Z (mm) and your measurements. If nothing is selected, all labelled markers are sent. Position is differentiated to velocity & acceleration on the Kinematics page.

Tool

Pick a tool, then click markers in the 3D view. Options for the active tool appear beneath it. Angles in degrees, distances in mm, areas in cm². Esc or empty-space click returns to Select.

Nothing selected. Choose a measurement or bone from the Measurements tab to edit it here, or click a marker to name it in the Markers tab.

Measurements

Smooth (Butterworth) Cutoff Hz

Gap-fill ≤ frames cubic-spline fill of short gaps

Markers

Names come from the TSV where present. Click a row (or its name field) to select and rename a marker; use Apply & next to sweep through unlabelled markers. Edit a name or colour inline on any row.

0 labelled 0 unlabelled 0 visible now

Row value

Merge markers

Qualisys can split one physical marker into two trajectories across a tracking dropout. Merge combines them into one marker. Non-destructive: the source slot is kept but emptied, and merges undo cleanly.

Target (keep)

Source (merge in, then empty)

Auto-merge if overlap ≤ frames

Above this many frames where both markers are present, you choose which one wins on the overlap.