How do I trigger a game object to move a desired distance at a desired speed?

Question

I have a ball that when it rolls over a tile it will cause the tile to move upwards pushing the ball up with it. My script is below. The parent object is a tile that moves up when the ball rolls over it and collides with the nested trigger object. The tile moves up but does not push the ball up with it. I assume it is because the tile moves too quickly as the ball does have a Rigidbody component attached to it. How can I trigger the movement of the tile and define the distance and speed that the tile should move up?

 public class Spring : MonoBehaviour
 {
 
 
     private void OnTriggerEnter(Collider other)
     {
         transform.parent.Translate(Vector3.up );
         
     }
 
 }

Answer 1

You assumed correctly. The tile needs to be a kinematic Rigidbody, and you need to use the MovePosition function. The tile collider cannot be a trigger.

You need to use two colliders if you want a trigger in the center of the platform. You could do something like this:

this is the script on the trigger collider in the center of the tile, that is a child of tile:

   public class TriggerDispatcher : MonoBehaviour
   {
     public GameObject target;

     private void OnTriggerEnter(Collider other) {
         if (other.CompareTag("Player"))
         {
             target.SendMessage("OnPlayerEnter", other);
         }
     }

this is the script of the tile

   public class TriggerDispatcher : MonoBehaviour
     {
         public float speed = 1f;
         public Vector3 target;
         private Vector3 startPos;

         public bool movingToTarget;

         private void Start() {
             startPos = transform.position;
         }

         private void OnPlayerEnter(Collider other) {

             movingToTarget = !movingToTarget;
         }

         private void FixedUpdate() {
             Vector3 destination;

             if (movingToTarget)
                 destination = startPos + target;
             else
                 destination = startPos;

             Vector3 movement = destination - transform.position;

             float distance = speed * Time.fixedDeltaTime;

             if (movement.magnitude > distance)
                 movement = movement.normalized * distance;

             GetComponent<Rigidbody>().MovePosition(transform.position + movement);
         }
     }

Now this can be simplified if you add start and end position markers for your platform, and use the SmoothDamp function:

     public class TriggerDispatcher : MonoBehaviour
     {
         public float speed = 1f;
         public float timeToEnd = 1f;
         public Transform startPos;
         public Transform endPos;
         public bool movingToTarget;

         private Vector3 velocity;

         private void Start() {
             startPos = transform.position;
         }

         private void OnPlayerEnter(Collider other) {

             movingToTarget = !movingToTarget;
         }

         private void FixedUpdate() {
             Vector3 destination;

             if (movingToTarget)
                 destination = endPos.position;
             else
                 destination = startPos.position;

             Vector3 newPos = SmoothDamp(
                 transform.position,
                 destination,
                 ref velocity,
                 timeToEnd,
                 speed);

             GetComponent<Rigidbody>().MovePosition(newPos);
         }
     }

How do I trigger a game object to move a desired distance at a desired speed?

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