Simpler Wheels (wheelCollider)

Questions & Answers
1

I’m making a game with potentially hundreds of cars on screen at one time… and I believe unity’s build-in wheel colliders do suspension calculations that are unnecessary to my game.

Is there a simpler(more efficient) method of making an object “slide and steer” along the terrain to simulate driving? I tried putting a “slippery” physics material on cubes and limit the friction direction and it kinda worked but was quite sketchy and didn’t seem right, maybe there’s a specific way of using “limited friction” that I don’t know about?

2

I had the same problem using wheelcolliders in a racing game. So, I wrote one myself. (C#)

/// <summary>
    ///  Use in FixedUpdate
	/// Define  maxForwardSpeed, grip somewhere ( I had mFS = 30f, g = 1.5f)
    /// </summary>
    /// <param name="inputForward"></param> range between -1..1
    /// <param name="inputSideways"></param> range between -1..1
    public void movement(float inputForward, float inputSideways) {
        //Normalize Inputs
        if (inputSideways < -1)
            inputSideways = -1;
        if (inputSideways > 1)
            inputSideways = 1;
        if (inputForward < -1)
            inputForward = -1;
        if (inputForward > 1)
            inputForward = 1;

        if (rigidbody.velocity.sqrMagnitude < maxForwardSpeed * maxForwardSpeed && isGrounded()) {

            //forwardSpeed
            rigidbody.AddRelativeForce(Vector3.forward * forwardSpeed * inputForward, ForceMode.Acceleration);
            //Angular damping
            if (inputSideways == 0) {
                rigidbody.angularVelocity *= 0.5f;
                //rigidbody.velocity = Vector3.
            }
            //Anti-Roll
            rigidbody.AddRelativeForce(Vector3.down * antiRoll);
            //Anti-Slide/Drift
            rigidbody.velocity = Vector3.Lerp(rigidbody.velocity, rigidbody.rotation * Vector3.forward * rigidbody.velocity.magnitude, grip * Time.deltaTime);

        }
    }
	
	bool isGrounded() {

        RaycastHit hit;
        if (Physics.Raycast(transform.position, transform.TransformDirection(Vector3.down), out hit, LayerMask.NameToLayer("Ground"))) {
            if(hit.distance - transform.localScale.y /2 < 1f) {
                //Debug.Log("Grounded");
                return true;
            } else {
                return false; ;
            }
        } else {
            return false;
        }      
    }

Add this code in a class which derives from Monobehaviour and add is as a new component to your car ( must have rigidbody attached).

A big plus is, that you can use the same car physics for both AI and Human Drivers. Just simulate the input Vector2 ([-1…1],[-1…1])