Vehicles

Note

The code is the same one tested on the Portuguese page, so names such as carro (car) and volante (steering) are in Portuguese.

Anastacio builds the vehicle for you from the Physics > Vehicle panel. You only configure the wheels and attach a controller.

1. Build the car

You need a chassis (the body) and one object per wheel.

1. Select the chassis. Under Properties > Physics, use Rigid Body and turn on the vehicle in the Vehicle panel.
2. In the wheel list, add one entry per wheel and pick its object.
3. For each wheel, set radius, suspension, whether it steers (front wheels) and whether it is driven.

Tip

The Vehicle demo that ships with the engine (demos/Vehicle folder) already has a car set up. Open it to see working values.

2. Drive with the ready-made component

Attach the VehiclePlayerComponent component (the demo’s vehicle_player_component.py file) to the chassis.

• W accelerates, S reverses, A/D steer;
• Space brakes, Left Shift is the handbrake;
• with gears registered in the Vehicle panel, shifting is automatic (or E/Q for manual).

The component publishes the vehicle_speed_kmh, vehicle_rpm and vehicle_gear properties on the chassis, useful for a speedometer.

Tip

By project convention, the chassis’ front points toward +Y. If the car reverses when you press W, turn on Invert Direction in the VehiclePlayerComponent properties.

3. Or control it from Python

getVehicle() returns the chassis’ vehicle (KX_VehicleWrapper). A minimal controller:

import Range
from Range import events, logic


class DirigirSimples(Range.types.KX_PythonComponent):
    args = {}

    def start(self, args):
        self.carro = self.object.getVehicle()

    def update(self):
        if self.carro is None:
            return
        tecla = logic.keyboard.inputs
        forca = 0.0
        if tecla[events.WKEY].active:
            forca = -1500.0
        elif tecla[events.SKEY].active:
            forca = 800.0
        volante = 0.0
        if tecla[events.AKEY].active:
            volante = 0.4
        elif tecla[events.DKEY].active:
            volante = -0.4

        for roda in range(self.carro.getNumWheels()):
            self.carro.applyEngineForce(forca, roda)
            self.carro.applyBraking(0.0, roda)
        self.carro.setSteeringValue(volante, 0)
        self.carro.setSteeringValue(volante, 1)

Attach it to the chassis. Wheels 0 and 1 are the first two in the panel’s list (the steering ones).

Note

The force’s sign depends on which way the chassis faces. If the car reverses with W, flip the signs.

Saving the car setup

vehicle.savePreset("//acerto.json") writes mass, suspension, friction and wheels to a file. vehicle.loadPreset(...) reapplies the setup to the same car, for example to switch between “asphalt” and “dirt”.

Caution

savePreset() fails if the vehicle’s Ray Cast Mask field is left at its default value (0): the engine internally stores -1, and its own validation rejects that value. Set the Ray Cast Mask manually in the Vehicle panel before saving the setup.