Wheels

Adds a virtual wheel to the draft vehicle and returns its zero-based index or false on failure.

The position is a suspension hard point in chassis-local space. Radius, width, suspension, traction, steering, drive and braking are configured before build().

Syntax#

vehicle.add_wheel(local_x, local_y, local_z, options=undefined)

Geometry and suspension options#

Control and tyre options#

var front_left = car.add_wheel(-0.8, 1.4, -0.2, {
    radius: 0.35,
    width: 0.2,
    steering: true,
    driven: true,
    suspension_frequency: 1.8,
    suspension_damping: 0.65
});

Current project integrations#

• Wheel settings and orientation›

Configuration object and setters#

var wheel = jolt_vehicle_wheel(-0.8, 1.4, -0.2);
wheel.set_radius(0.35);
wheel.set_driven(true);
wheel.set_steering(true);
var wheel_index = car.add_wheel(wheel);

Configuration factories return a GML settings object and create no physics. Their setters return self, the settings object, and do not confirm that a value is valid. Fields are consumed and validated by jolt_vehicle, add_wheel or add_differential. An omitted field preserves the corresponding options default described above. Editing settings after consumption does not change an existing vehicle, wheel or differential. Settings need no destroy.

Vehicle creation returns undefined on failure. add_differential returns Boolean; add_wheel returns a numeric zero-based index or Boolean false on failure. Index 0 is success: do not use only if (!wheel_index). Complete wheel/differential configuration before build().

set_orientation(fx,fy,fz,ux=0,uy=0,uz=1) uses chassis-local directions. Forward/up must be finite, nonzero and perpendicular; add_wheel validates them. set_forward(x,y,z=0) also selects default up +Z. A failure after native wheel configuration starts is not atomic; correct the data and recreate the draft after failure.

Verified operation contracts#

These contracts distinguish units, return values, errors and lifetime according to the current implementation. Check results: false, 0 and undefined can mean different things for different methods.