How to prevent lerp from slowing down

Questions & Answers
1

void Update()
{
if (targetPos != null && (isMoving))
{
this.transform.LookAt(targetPos);
this.transform.position = Vector3.Lerp(transform.position, targetPos, Time.deltaTime * speed);
}

}

Im bulding bubbles game, the bubble is projected but slowing down near the target, is there any way go around it?

3

The point of “lerping yourself” towards the target is to get that fast-then-slow movement. Main use is there’s no limit on speed. For example, if you teleport, a camera using normal movement will slowly scroll to catch up with you. A lerping camera will zoom right over.

If you don’t want fast then slow movement, use one of the other methods of moving. A general way is using MoveTowards with a speed you control. The syntax is the same as lerp, but the 3rd input is more the speed in meters/frame::

float spd = 5;

  trans.pos = Vector3.MoveTowards( trans.pos, targetPos, spd*Time.deltaTime);
  // 5 meters/sec

That moves at a constant rate of spd meters per second. To change the rate, change speed:

  // slow down to 2 meters/sec:
  spd -= 2*Time.deltaTime;
  if(spd<2) spd=2;

  // quickly get faster, up to 20 M/sec:
  spd += 10*Time.deltaTime;
  if(spd>20) spd=20;
2

I believe that the final parameter in Lerp is supposed to be a value between 0 and 1, where 0 is 0% to the target (at transform.position) and 1 is 100% to the target (at targetPos). The reason it would slow down is because Time.deltaTime * speed will probably never move towards 1 and give you what you are looking for.

Here is an example of how you could modify this to work; you will need to figure out how much time you want the move to take, but you can probably derive this from the speed with speed = distance / time => time = speed / distance.

float timeToLerp = 2; //lerp for two seconds.
Vector3 startingPosition;

float timeLerped = 0.0f;

void Start()
{
    startingPosition = transform.position;
}

void Update()
{
    timeLerped += Time.deltaTime;
    transform.position = Vector3.Lerp(startingPosition, targetPos, timeLerped / timeToLerp);
}

Second, as you’ll see in the code example, you need to save the starting position in a separate variable. If you are updating “transform.position” at the same time that you are using it as the starting position in the Lerp, you’ll get some weird results.

4

Instead of using your current position with transform.position, try storing your current position that doesn’t change as a start position and use that fixed position for the lerp. Because by using transform.position you continuously update your startposition.