# Multiple LERP?
**URL:** https://discussions.unity.com/t/multiple-lerp/402726
**Category:** Scripting
**Tags:** Scripting
**Created:** [November 30, 2009, 9:53am UTC](https://discussions.unity.com/t/multiple-lerp/402726 "2009-11-30T09:53:20Z")
**Posts on this page:** 18
**Page:** 1
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 9:53am UTC](https://discussions.unity.com/t/multiple-lerp/402726/1 "2009-11-30T09:53:20Z")
I am having problems doing a LERP after another LERP. Only the last LERP is executed ☹ What am I doing wrong?
```auto
function Update() {
childarr[0].transform.position = Vector3.Lerp(splinearr[0].transform.position, splinearr[1].transform.position, tid*smooth);
childarr[0].transform.position = Vector3.Lerp(splinearr[1].transform.position, splinearr[2].transform.position, tid*smooth);
}
```
---
### Author:  [@tomvds](https://discussions.unity.com/u/tomvds)
#### Post date: [November 30, 2009, 10:02am UTC](https://discussions.unity.com/t/multiple-lerp/402726/2 "2009-11-30T10:02:13Z")
> [@""](#):
>
> I am having problems doing a LERP after another LERP. Only the last LERP is executed ☹ What am I doing wrong?
At the moment, you’re assigning the result of the first lerp to the objects position. After that you assign the second lerp to the objects position. Assigning a value to a position overwrites whatever value it had before, so only your second lerp is used.
You’ll need to specify how the two lerps are supposed to be combined into the position value of your object. Are they to be averaged, added, subtracted, or again lerped themselves? Only you can know ;).
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 10:03am UTC](https://discussions.unity.com/t/multiple-lerp/402726/3 "2009-11-30T10:03:00Z")
I want the transformations to happen right after each other. I need to do more than just these two LERPs.
---
### Author:  [@anon\_25600666](https://discussions.unity.com/u/anon_25600666)
#### Post date: [November 30, 2009, 10:04am UTC](https://discussions.unity.com/t/multiple-lerp/402726/4 "2009-11-30T10:04:53Z")
You’re performing one lerp and storing the result. Then you’re performing a different lerp and storing the result… over the result of the first lerp.
I think what you mean is something along the lines of…
```auto
temp = Lerp(var1, var2, amount1);
output = Lerp(temp, var 3, amount2);
```
or
```auto
output = Lerp( Lerp( var1, var2, amount1 ), var3, amount2);
```
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 10:14am UTC](https://discussions.unity.com/t/multiple-lerp/402726/5 "2009-11-30T10:14:17Z")
The above doesn’t work. When I do this, the object LERPS between the first and last position, but doesn’t come by the second position.
I want movement like this:
- Lerp from A to B
- Lerp from B to C
- Lerp from C to D
- Lerp from D to E
I am unsure how to do this 😢
---
### Author:  [@anon\_25600666](https://discussions.unity.com/u/anon_25600666)
#### Post date: [November 30, 2009, 10:20am UTC](https://discussions.unity.com/t/multiple-lerp/402726/6 "2009-11-30T10:20:07Z")
If you’re trying to do something along the lines of:
[Bézier curve - Wikipedia](http://en.wikipedia.org/wiki/B%C3%A9zier_curve) (the animated examples are really illustrative on that page)
```auto
// Three points point1-3
position1 = Lerp(point1, point2, amount);
position2 = Lerp(point2, point3, amount);
output = Lerp(position1, position2, amount);
```
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 10:25am UTC](https://discussions.unity.com/t/multiple-lerp/402726/7 "2009-11-30T10:25:27Z")
I just want to move the object, without any fancy interpolation.
Move in a straight line from point to point is what I want 🙂
---
### Author:  [@anon\_25600666](https://discussions.unity.com/u/anon_25600666)
#### Post date: [November 30, 2009, 10:32am UTC](https://discussions.unity.com/t/multiple-lerp/402726/8 "2009-11-30T10:32:05Z")
Sorry, I was overthinking the problem 😄
Then there is no need to even think about more than one Lerp at a time.
Here’s a suggestion.
Make an array[ ] of locations and a counter “i” that starts at 0, then Lerp between array _and array[i+1] and increase your Lerp amount from 0 to 1 over your time period. When the Lerp amount is 1, then reset it to 0, i++, and Lerp position between elements array and array[i+1] (checking to see if i+1 \> array.length, of course)._
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 10:40am UTC](https://discussions.unity.com/t/multiple-lerp/402726/9 "2009-11-30T10:40:59Z")
I will try that, thank you 🙂
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 1:24pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/10 "2009-11-30T13:24:42Z")
Still can’t get this to work ☹
It still only does the last LERP.
```auto
for (var i : int = 0; i < splinearr.length; i++) {
if (i+1 > splinearr.length) {
break;
}
childarr[0].transform.position = Vector3.Lerp(splinearr[i].transform.position, splinearr[i+1].transform.position, tid*smooth);
tid = 0;
}
```
---
### Author:  [@anon\_25600666](https://discussions.unity.com/u/anon_25600666)
#### Post date: [November 30, 2009, 1:45pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/11 "2009-11-30T13:45:57Z")
You’re doing the same thing here that you were doing in the first place. You’re doing all the Lerps in a single frame, and storing them all in the same place.
A “for” loop isn’t an appropriate structure here, I’m afraid; you don’t want to iterate through the entire array in a single frame. You want to check each frame whether you want to go to the next pair of points, rather than doing the whole lot.
In each frame:
Check to see if the Lerp amount has reached 1.0. If it has, set it to zero and increment i - use the next pair of points from now on. If it hasn’t, add amount \* Time.deltaTime and use the current pair of points.
I hope that makes sense, I’m bashing this out on my way out the door, I’ll check back a bit later!
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 7:12pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/12 "2009-11-30T19:12:58Z")
Still having a bit problems here 🙂
```auto
if (tid * smooth <= 0) {
var i : int = 0;
for (var j : int = 0; j < childarr.length; j++) {
childarr[j].transform.position = Vector3.Lerp(splinearr[i].transform.position, splinearr[i+1].transform.position, tid*smooth);
}} else
if (tid * smooth >= 1.0) {
i++;}
}
```
shouldn’t this be working?
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 8:03pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/13 "2009-11-30T20:03:55Z")
The code is, of course, in Update()…
---
### Author:  [@anon\_25600666](https://discussions.unity.com/u/anon_25600666)
#### Post date: [November 30, 2009, 8:27pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/14 "2009-11-30T20:27:40Z")
```auto
private var i : int = 0;
function Update() {
// Increase lerpAmount by a frame-rate independent value
lerpAmount += lerpRate * Time.deltaTime;
// Is lerpAmount over 1?
if (lerpAmount > 1.0) {
// Decrement lerpAmount to below 1.0 and increment i every time!
while (lerpAmount > 1.0) {
lerpAmount--;
i++;
} // End while (lerpAmount > 1.0)
// Have we gone past the end of splineArr?
if (i + 1 > splineArr.length) {
// Your code to handle reaching the end of splineArr here!
} // End if (i + 1 > splineArr.length)
} // End if (lerpAmount > 1.0)
// Lerp using values from the array and lerpAmount
var lerpedPosition : Vector3 = Vector3.Lerp(splineArr[i], splineArr[i+1], lerpAmount);
}// End function Update()
```
I’m not sure what you were using childArr[ ] for in your code, but I hope what I wrote above is clear enough for you to adapt to your needs. It looks about right, although I have a strange blindness for the differences between \< and \> and keeping array indices straight that normally requires a bit of tweaking until I get things the right way around.
---
### Author:  [@Eric5h5](https://discussions.unity.com/u/Eric5h5)
#### Post date: [November 30, 2009, 8:31pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/15 "2009-11-30T20:31:54Z")
> [@""](#):
>
> The code is, of course, in Update()…
Don’t use Update. You can’t schedule events in Update (without a lot of ugly code hacking anyway) because it runs every frame. Use coroutines instead.
–Eric
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 8:56pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/16 "2009-11-30T20:56:34Z")
Think I got this to work 🙂 I’ll post some code later on, I need to play around for a while now 🙂
Thank you very much for clearing some important stuff in your replies, DMJ. Thank you others as well 🙂
---
### Author:  [@anon\_89542](https://discussions.unity.com/u/anon_89542)
#### Post date: [November 30, 2009, 8:57pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/17 "2009-11-30T20:57:59Z")
> [@""](#):
>
> > [@""](#):
> >
> > The code is, of course, in Update()…
>
> Don’t use Update. You can’t schedule events in Update (without a lot of ugly code hacking anyway) because it runs every frame. Use coroutines instead.
>
> –Eric
Thanks for the tip! I will look into this 🙂
---
### Author:  [@Kevin\_h](https://discussions.unity.com/u/Kevin_h)
#### Post date: [January 20, 2017, 11:25pm UTC](https://discussions.unity.com/t/multiple-lerp/402726/18 "2017-01-20T23:25:38Z")
If people are still looking for an A to B to C back to A and so on lerp loop here is one:
```csharp
public Transform [] positions;
public int i = 0;
public float lerpAmount = 0;
public float lerpSpeed = 1.2f;
void Update () {
//The lerpfloat should always be reset back to 0 otherwise you'd start teleporting.
if (lerpAmount >= 1f)
lerpAmount = 0;
lerpAmount += lerpSpeed * Time.deltaTime;
//Here the lerp from place to place takes place, I used %3 because I've 3 elements in my array, this way it keeps looping between these positions.
transform.position = Vector3.Lerp (positions [i%3].position, positions [(i+1)%3].position, lerpAmount);
//The code explains it self I guess.
transform.LookAt (positions[(i+1)%3]);
//since lerp never actually reaches its target you need to check for the distance and can't just say if the lerps final position is reached up "i" by 1.
if (Vector3.Distance (transform.position, positions [(i + 1)%3].position) < 0.13333) {
i ++;
lerpAmount = 1;
}
}
```
Should be easy enough to transform into JS and use it for an A to B to C … to ENDPOINT script.