tcxQTMRT

TrussC addon for receiving motion-capture data from Qualisys Track Manager (QTM) over the QTM Real-Time (RT) protocol.

Wraps the official qualisys_cpp_sdk (vendored under qualisys_cpp_sdk/, built from source) behind a small tcx::QTMRT class.

Architecture

QTM is the Windows-only server that drives the cameras and tracks. This addon is the client — it connects over the network and receives the stream, and runs on Linux / macOS / Windows. (Same model as OptiTrack Motive + NatNet: server on Windows, client anywhere.)

Features

• ✅ 6DOF rigid bodies (tc::Mat4 transform + position + active flag)
• ✅ 3D labeled markers
• ✅ 3D unlabeled markers
• ✅ Background receive thread, double-buffered lock-free reads on the main thread
• ✅ Automatic reconnect
• ⏳ Skeletons / analog / force plates — not yet exposed

Rotation note: QTM delivers 6DOF rotation as a column-major 3×3 matrix; it is mapped into TrussC's column-vector Mat4. Not yet validated on live hardware — if a body's axes look mirrored, transpose the 3×3 in buildMatrix() (see src/tcxQTMRT.cpp).

Usage

#include "tcxQTMRT.h"

tcx::QTMRT qtm;

void tcApp::setup() {
    qtm.setup("192.168.0.1");   // QTM host (base RT port 22222)
}

void tcApp::update() {
    qtm.update();               // non-blocking; call once per frame
}

void tcApp::draw() {
    for (size_t i = 0; i < qtm.getNumRigidBody(); i++) {
        const auto& rb = qtm.getRigidBodyAt(i);
        // rb.getMatrix(), rb.getPosition(), rb.name, rb.isActive()
    }
    for (size_t i = 0; i < qtm.getNumMarker(); i++)
        drawBox(qtm.getMarker(i), 15);
}

Positions are in millimetres (QTM native). Use setScale(s) or setTransform(Mat4) to convert; scale is applied to positions only, not to body orientation.

Examples

• example-basic — 3D viewer: markers as boxes, rigid bodies as axis gizmos.
• example-qtmrt2osc — bridge that forwards QTM rigid bodies as OSC (/qtm/rigidbody …), for OSC-based consumers like tcxFSportsMocap or TouchDesigner. Depends on tcxOsc.

Build

The Qualisys SDK builds from source via add_subdirectory, so there are no prebuilt binaries to manage.

• Linux / macOS: no extra dependencies.
• Windows: ws2_32 + iphlpapi (propagated automatically from the SDK target).

Add tcxQTMRT to your project's addons.make and run trusscli update.

License

MIT (addon glue). The bundled qualisys_cpp_sdk keeps its own license — see LICENSE.qualisys_cpp_sdk.md.