Can someone help me debug some vector math stuff, Please?

Unity Engine
1

I am trying to make a ball react to a wall and other objects.

function OnCollisionEnter(collision : Collision){
	var newVelocity;
	var normalHit = collision.contacts[0].normal;
	newVelocity = rigidbody.velocity + normalHit;
	var newVelocity1;
	newVelocity1 = Vector3(newVelocity) * Vector3(normalHit);
	var newVelocity2;
	newVelocity2 = Vector3.Dot(velocityMultiplier, newVelocity);
	var newVelocity3;
	newVelocity3 = newVelocity2 - rigidbody.velocity;
	rigidbody.velocity = newVelocity3;
}
2

My main theory is one i found on here earlier…

Velocity New = 2 * (velocity+normalVector) * normalVector - velocity

3

Ok so I have most of this working, i have gotten the ball to bounce a couple of times. When it bounces however it is getting faster, which is cool but is causing clipping issues after a certain point. The ball only bounces in the Y plane, and when the ball hits an X plane barrier it passes through it.

Heres my bounce code for the ball:

function OnCollisionStay(collision : Collision){
	print("I hit");
	print(rigidbody.velocity);
	var reflection;
	var myVelocity;
	myVelocity = rigidbody.velocity;
	var hitNormal = collision.contacts[0].normal;
	reflection = -2 * (Vector3.Dot(myVelocity, hitNormal)) * hitNormal - myVelocity;
	rigidbody.velocity = reflection;
	print(rigidbody.velocity);
}

Any thoughts?

4

Why are you trying to program in basic physics collision reactions when they are programmed in?

Can’t you create a physics material and set bounciness, etc and let the PhysX engine handle it?

Perhaps try this:

reflection = -2 * (Vector3.Dot(myVelocity.normalized, hitNormal)) * hitNormal - myVelocity.normalized;
rigidbody.velocity = reflection * myVelocity.magnitude;

If you want the ball to get slower with each impact, do…

rigidbody.velocity = reflection * myVelocity.magnitude * dampFactor;

Where dampFactor is between [0,1] if you want the ball to get slower, or [1,Infinity] if you want it to get faster. Also, make sure your rigid body is set to CONTINUOUS.