Vector3.Lerp

Description

Linearly interpolates between two vectors.

Interpolates between the vectors a and b by the interpolant t. The parameter t is clamped to the range [0, 1]. This is most commonly used to find a point some fraction of the way along a line between two endpoints (e.g. to move an object gradually between those points).

When t = 0 returns a. When t = 1 returns b. When t = 0.5 returns the point midway between a and b.

    // Transforms to act as start and end markers for the journey.
    var startMarker: Transform;
    var endMarker: Transform;

    // Movement speed in units/sec.
    var speed = 1.0;

    // Time when the movement started.
    private var startTime: float;

    // Total distance between the markers.
    private var journeyLength: float;

    function Start() {
        // Keep a note of the time the movement started.
        startTime = Time.time;

        // Calculate the journey length.
        journeyLength = Vector3.Distance(startMarker.position, endMarker.position);
    }

    // Follows the target position like with a spring
    function Update () {
        // Distance moved = time * speed.
        var distCovered = (Time.time - startTime) * speed;

        // Fraction of journey completed = current distance divided by total distance.
        var fracJourney = distCovered / journeyLength;

        // Set our position as a fraction of the distance between the markers.
        transform.position = Vector3.Lerp(startMarker.position, endMarker.position, fracJourney);
    }

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Transform startMarker;
    public Transform endMarker;
    public float speed = 1.0F;
    private float startTime;
    private float journeyLength;
    void Start() {
        startTime = Time.time;
        journeyLength = Vector3.Distance(startMarker.position, endMarker.position);
    }
    void Update() {
        float distCovered = (Time.time - startTime) * speed;
        float fracJourney = distCovered / journeyLength;
        transform.position = Vector3.Lerp(startMarker.position, endMarker.position, fracJourney);
    }
}

See Also: Slerp, LerpUnclamped.