Lifting platforms is not working as it should - unity3d

Question

I would like to make some lifting platforms in my game, so if the platform went down, the characters can't go over it. I have written a script for it, but for some reason the "lifting up" is not working as intended. It won't go back to its starting place, but it will go a bit below. And for some reason it won't go smoothly to the place where it should, just "teleport" there and done. I thougt multiplying Time.deltaTime with a const will help, but it is the same.
Here is my code, any help would be appreciated:
public class LiftingPlatform : MonoBehaviour {
private Transform lift;
private bool isCanBeLifted;
private float timeToLift;
public float timeNeededToLift = 5f;
private Vector3 startPos;
private Vector3 downPos;
private Vector3 shouldPos;
private bool isDown;
public GameObject[] collidingWalls;
// Use this for initialization
void Start () {
lift = transform;
isCanBeLifted = true;
timeToLift = 0f;
isDown = false;
startPos = transform.position;
downPos = new Vector3(startPos.x, startPos.y - 5f, startPos.z);
}
// Update is called once per frame
void Update () {
timeToLift += Time.deltaTime;
if (timeToLift >= timeNeededToLift) {
if (isCanBeLifted) {
if (isDown) {
shouldPos = Vector3.Lerp(startPos, downPos, Time.deltaTime * 10);
lift.position = new Vector3(shouldPos.x, shouldPos.y, shouldPos.z);
isDown = true;
}
else if (!isDown) {
shouldPos = Vector3.Lerp(downPos, new Vector3(startPos.x, startPos.y, startPos.z), Time.deltaTime * 10);
lift.position = new Vector3(shouldPos.x, shouldPos.y, shouldPos.z);
isDown = false;
}
}
timeToLift = 0;
}
if (!isDown) {
for (int i = 0; i < collidingWalls.Length; i++) {
collidingWalls[i].SetActive(true);
}
}
else if (isDown) {
for (int i = 0; i < collidingWalls.Length; i++) {
collidingWalls[i].SetActive(false);
}
}
}
void OnTriggerEnter(Collider collider) {
if (collider.tag == "Player" || collider.tag == "Enemy") {
isCanBeLifted = false;
}
}
void OnTriggerExit(Collider collider) {
if (collider.tag == "Player" || collider.tag == "Enemy") {
isCanBeLifted = true;
}
}
}
These lifting platforms are a child of another Platforms object.

Answer 1

It doesn't look like you are updating the object's position every frame. You are only checking if the total time passed is greater than the time needed to lift, and then updating the position to a value that is dependent on the delta time (using the Vector3.Lerp function).
What I would do is in the update step, if timeToLift is greater then timeNeededToLift, subtract the latter from the former and invert the value of isDown. Then, in your Vector3.Lerp, make the third argument (timeToLift / timeNeededToLift) instead of (Time.deltaTime * 10). Can you try that and see if it works?
The third argument for Vector3.Lerp is the "blending factor" between the two vectors, 0 is the first vector, 1 is the second, and 0.5 is in between. If the total time is greater than the time needed to lift, but the delta time is not greater than 1, it will get the position of the platform using a blending factor of less than 1, resulting in a platform that didn't move fully.