SmoothCamera help

Unity Engine
1 
function LateUpdate () {
	// Early out if we don't have a target
	if (!target)
		return;
	
	// Calculate the current rotation angles
	wantedRotationAngle = target.eulerAngles.y;
	wantedHeight = target.position.y + height;
		
	currentRotationAngle = transform.eulerAngles.y;
	currentHeight = transform.position.y;
	
	// Damp the rotation around the y-axis
	currentRotationAngle = Mathf.LerpAngle (currentRotationAngle, wantedRotationAngle, rotationDamping * Time.deltaTime);

	// Damp the height
	currentHeight = Mathf.Lerp (currentHeight, wantedHeight, heightDamping * Time.deltaTime);

	// Convert the angle into a rotation
	currentRotation = Quaternion.Euler (0, currentRotationAngle, 0);
	
	// Set the position of the camera on the x-z plane to:
	// distance meters behind the target
	transform.position = target.position;
	transform.position -= currentRotation * Vector3.forward * distance;

	// Set the height of the camera
	transform.position.y = currentHeight;
	
	// Always look at the target
	transform.LookAt (target);
}

Now Look At these codes, I don’t understand this part
transform.position -= currentRotation * Vector3.forward * distance;
why does the rotation is multiplied by vector3.forward ???
I don’t understand the Math behind there.

any url on tutorials about multiplying rotation and positions will help. thanks.:wink:

2

yeah, its a stretch. Multipying a Quaternion by a vector gives you a position based off the direction. If that vector is normalized (as Vector3.forward is) then it gives you back a normal based off the rotation.

Think of it this way: If you model was at world zero, facing forward (Quaternion.identity) multiplying the rotation (Quaternion.identity * Vector3.forward) would produce… Vector3.forward. Any other rotation, would give you the forward vector of the rotation.

Lets check out an example… put this on a cube, target another cube, move the other cube around while the game is running and you are in the editor.

var target : Transform;
var damp=2.0;

function Update () {
	var currentPos=transform.rotation * Vector3.forward * 10;
	
	var targetPos=Vector3.zero;
	if(target) targetPos=target.position;
	var rotation=transform.rotation;
	transform.LookAt(targetPos);
	
	var lookPos=transform.rotation * Vector3.forward * 10;
	
	transform.rotation=Quaternion.Lerp(rotation, transform.rotation, damp * Time.deltaTime);
	
	var actualPos=transform.rotation * Vector3.forward * 10;
	
	Debug.DrawLine (transform.position, transform.position + currentPos, Color.red);
	Debug.DrawLine (transform.position, transform.position + actualPos, Color.yellow);
	Debug.DrawLine (transform.position, transform.position + lookPos, Color.green);
	
	// currentPos is the initial rotation
	// actualPos is the rotation lerped
	// lookPos is the rotation based on where it wants to be
}
3

Good Help Thanks.