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Tags: unity, vehicle, character-controller, wheel-collider, friction, drag, torque, raycast, game-dev Last updated: 2026-06-27

Vehicle / Character Controllers Cheatsheet

Quick Reference

CharacterController Component

Key Properties

Basic Movement

CharacterController cc = GetComponent<CharacterController>();

Vector3 move = (transform.right * Input.GetAxis("Horizontal")
              + transform.forward * Input.GetAxis("Vertical"));
move *= speed;

if (!cc.isGrounded) move.y += Physics.gravity.y * Time.deltaTime;

cc.Move(move * Time.deltaTime);

Jumping

float verticalVelocity;
bool isGrounded;

void Update() {
    isGrounded = cc.isGrounded;
    if (isGrounded && verticalVelocity < 0)
        verticalVelocity = -2f;   # Stick to ground

    if (isGrounded && Input.GetButtonDown("Jump"))
        verticalVelocity = Mathf.Sqrt(jumpHeight * -2f * Physics.gravity.y);

    verticalVelocity += Physics.gravity.y * Time.deltaTime;
    Vector3 move = inputMove * speed;
    move.y = verticalVelocity;
    cc.Move(move * Time.deltaTime);
}

Slope Handling

• cc.isGrounded returns false on slopes steeper than Slope Limit.

RaycastHit hit;
Physics.Raycast(transform.position, Vector3.down, out hit, 2f);
float slopeAngle = Vector3.Angle(hit.normal, Vector3.up);
bool tooSteep = slopeAngle > cc.slopeLimit;

Rigidbody Character Controller

Force-Based Movement

Rigidbody rb = GetComponent<Rigidbody>();
Vector3 targetVel = inputDir * speed;
Vector3 delta = targetVel - new Vector3(rb.velocity.x, 0, rb.velocity.z);
rb.AddForce(delta, ForceMode.VelocityChange);

# Jump
if (isGrounded && Input.GetButtonDown("Jump"))
    rb.AddForce(Vector3.up * jumpForce, ForceMode.Impulse);

Ground Detection (SphereCast)

bool CheckGrounded() {
    return Physics.SphereCast(
        transform.position + Vector3.up * 0.1f,
        radius, Vector3.down, out RaycastHit hit,
        0.15f, groundMask);
}

Movement Settings Tuning

WheelCollider (Vehicle Physics)

Setup Checklist

1. Add Rigidbody to car root (mass 1000–1500 kg).
2. Add WheelCollider to each wheel GameObject.
3. Assign WheelCollider to a script for motor/steering/brake control.
4. Add a visual wheel mesh (separate Transform, synced to WheelCollider in Update).

WheelCollider Properties

Friction Curve

WheelFrictionCurve friction = wheel.forwardFriction;
friction.extremumSlip = 0.4f;     # Slip where grip peaks
friction.extremumValue = 2f;      # Maximum grip multiplier
friction.asymptoteSlip = 0.8f;    # Slip where grip plateaus
friction.asymptoteValue = 1.5f;   # Grip at plateau
friction.stiffness = 1f;          # Overall grip multiplier
wheel.forwardFriction = friction;

Motor, Steering, Brakes

# Motor torque (Nm)
wheel.motorTorque = Input.GetAxis("Vertical") * motorForce;

# Steering angle (degrees)
wheel.steerAngle = Input.GetAxis("Horizontal") * maxSteerAngle;

# Brake torque (Nm)
wheel.brakeTorque = Input.GetKey(KeyCode.Space) ? brakeForce : 0f;

Wheel Visual Sync

void Update() {
    wheelCollider.GetWorldPose(out Vector3 pos, out Quaternion rot);
    wheelVisual.position = pos;
    wheelVisual.rotation = rot;
}

Vehicle Tuning Tips

Raycast-Based Vehicle Controller

Alternative to WheelCollider — more control, less PhysX magic.

Hover / Anti-gravity Pattern

void FixedUpdate() {
    RaycastHit hit;
    float hoverHeight = 2f;
    float hoverForce = 100f;

    if (Physics.Raycast(transform.position, Vector3.down,
        out hit, hoverHeight)) {
        float compression = 1f - (hit.distance / hoverHeight);
        Vector3 force = Vector3.up * hoverForce * compression;
        rb.AddForceAtPosition(force, transform.position);
        rb.AddForceAtPosition(-rb.velocity * damping, transform.position);
    }

    # Apply torque for rotation/steering
    rb.AddTorque(transform.up * steerInput * torque);
}

Raycast Suspension (per-corner)

# Place ray origin above each wheel position
Vector3 rayOrigin = wheelPositions[i] + Vector3.up * maxSuspension;
if (Physics.Raycast(rayOrigin, Vector3.down, out hit, maxSuspension * 2f)) {
    float compRatio = 1f - (hit.distance / (maxSuspension * 2f));
    rb.AddForceAtPosition(Vector3.up * springStrength * compRatio,
                          wheelPositions[i]);
}

Friction & Drag Reference

Choosing an Approach