@eulerjs/vehicle

Ray-cast vehicles for eulerjs: a chassis body carried by wheels, each a ray down from its suspension mount to whatever ground is under it, flat or not, still or moving, with a spring and damper between them and a tyre that grips up to a limit.

npm install @eulerjs/vehicle @eulerjs/core three

import { RaycastVehicle } from '@eulerjs/vehicle';

const vehicle = chassis.addBehavior(
  new RaycastVehicle({
    wheels: mounts.map((mount) => ({ mount, radius: 0.32, suspensionLength: 0.35, springStiffness: 30_000, springDamping: 2400, grip: 1 })),
  }),
);
// every step, or whenever the driver does something
vehicle.wheels[0].steerAngle = vehicle.wheels[1].steerAngle = 0.3;
for (const wheel of vehicle.wheels) wheel.driveForce = 1500;

Each wheel takes a steerAngle, a driveForce and a brakeForce (which stops the wheel, never drives it backward), and its grip can be changed, as a handbrake does to the rear tyres. The tyre's forces grow with how much it slips, up to its grip times the load on it; beyond that it slides, which is how a car drifts, skids and spins out. Braked on a slope, it stands still. The wheels push back on what they stand on, so a car on a crate presses it into the ground. After each step every wheel reports whether it is on the ground, its compression, load, contact point and normal, what it stands on, and its centre and spin, for drawing it. A wheel stands only on ground that faces up along its strut, never a wall or a tree's trunk, nor anything its ray starts inside (as it will with the chassis pressed against something); at the end of its travel a bump stop holds the chassis up.

For a racing car, tyres: 'slip' gives each wheel a spin of its own, driven and braked by driveTorque and brakeTorque, and a tyre that pulls with how much it slips along and across, on a tyre curve: it peaks, grips less past its peak, and less a newton under more load, so a wheel spins up, locks and slides as a real one does. A surface callback says what the ground is like where each wheel touches it, its grip, its drag and its height, so that kerbs, grass and gravel can all be one flat collider.

The engine, gears, steering feel and air drag are yours: the city example builds a hatchback on it, and the formula car example a Formula 1 car on slip tyres. Needs three 0.166 or later. See the guide.

MIT licensed.