Version: 2021.3
LanguageEnglish
• C#

# Vector3.Lerp

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## Declaration

public static Vector3 Lerp(Vector3 a, Vector3 b, float t);

### Parameters

 a Start value, returned when t = 0. b End value, returned when t = 1. t Value used to interpolate between a and b.

### Returns

Vector3 Interpolated value, equals to a + (b - a) * t.

### Description

Linearly interpolates between two points.

Interpolates between the points `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).

The value returned equals a + (b - a) * t (which can also be written a * (1-t) + b*t).
When `t` = 0, Vector3.Lerp(a, b, t) returns `a`.
When `t` = 1, Vector3.Lerp(a, b, t) returns `b`.
When `t` = 0.5, Vector3.Lerp(a, b, t) returns the point midway between `a` and `b`.

```// A short example of Vector3.Lerp usage.
// Add it to an object in your scene, and at Play time it will draw in the Scene View a small yellow line between the scene origin, and a position interpolated between two other positions (one on the up axis, one on the forward axis).using UnityEngine;public class ExampleClass : MonoBehaviour
{
public int interpolationFramesCount = 45; // Number of frames to completely interpolate between the 2 positions
int elapsedFrames = 0;    void Update()
{
float interpolationRatio = (float)elapsedFrames / interpolationFramesCount;        Vector3 interpolatedPosition = Vector3.Lerp(Vector3.up, Vector3.forward, interpolationRatio);        elapsedFrames = (elapsedFrames + 1) % (interpolationFramesCount + 1);  // reset elapsedFrames to zero after it reached (interpolationFramesCount + 1)        Debug.DrawLine(Vector3.zero, Vector3.up, Color.green);
Debug.DrawLine(Vector3.zero, Vector3.forward, Color.blue);
Debug.DrawLine(Vector3.zero, interpolatedPosition, Color.yellow);
}
}
```
```// A longer example of Vector3.Lerp usage.
// Drop this script under an object in your scene, and specify 2 other objects in the "startMarker"/"endMarker" variables in the script inspector window.
// At play time, the script will move the object along a path between the position of those two markers.using UnityEngine;
using System.Collections;public class ExampleClass : MonoBehaviour
{
// Transforms to act as start and end markers for the journey.
public Transform startMarker;
public Transform endMarker;    // Movement speed in units per second.
public float speed = 1.0F;    // Time when the movement started.
private float startTime;    // Total distance between the markers.
private float journeyLength;    void Start()
{
// Keep a note of the time the movement started.
startTime = Time.time;        // Calculate the journey length.
journeyLength = Vector3.Distance(startMarker.position, endMarker.position);
}    // Move to the target end position.
void Update()
{
// Distance moved equals elapsed time times speed..
float distCovered = (Time.time - startTime) * speed;        // Fraction of journey completed equals current distance divided by total distance.
float fractionOfJourney = distCovered / journeyLength;        // Set our position as a fraction of the distance between the markers.
transform.position = Vector3.Lerp(startMarker.position, endMarker.position, fractionOfJourney);
}
}
```