Force in AddForce with ForceMode.Impulse insconsistent

Questions & Answers
1

Sometimes my player jumps relatively high, but then he jumps relatively low. I tried several methods, but none of them worked.

using System.Collections;
using System.Collections.Generic;
using UnityEngine.SceneManagement;
using UnityEngine;

public class PlayerController : MonoBehaviour
{
    public Rigidbody rb;
    public GameObject cam1;
    public Transform playerBody;
    RaycastHit hit;
    RaycastHit hitGround;

    public float MoveForce = 10f;
    public float jumppadForce = 10f;

    public bool hasKey;
    public bool isJumping;

    private void Update()
    {
        if(Physics.Raycast(cam1.transform.position, cam1.transform.forward, out hit, 4))
        {
            if (Input.GetMouseButtonDown(0))
            {
                switch (hit.transform.gameObject.tag)
                {
                    case "key":
                        Destroy(hit.transform.gameObject);
                        hasKey = true;
                        break;
                    case "lock":
                        if (hasKey)
                        {
                            SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex + 1);
                        }
                        break;

                }
            }

            if (Input.GetMouseButton(0))
            {
                switch (hit.transform.gameObject.tag)
                {
                    case "movableJumppad":
                        hit.transform.SetParent(playerBody);
                        break;
                }
            }

            if (Input.GetMouseButtonUp(0))
            {
                switch (hit.transform.gameObject.tag)
                {
                    case "movableJumppad":
                        hit.transform.SetParent(null);
                        break;
                }
            }
        }

        // part of jumping mechanic
        if(Physics.Raycast(transform.position, Vector3.down, out hitGround, 1.2f))
        {
            switch (hitGround.transform.gameObject.tag)
            {
                case "jumppad":
                    isJumping = false;
                    break;
                case "movableJumppad":
                    isJumping = false;
                    break;
            }
        }
        else
        {
            isJumping = true;
        }
    }

    // Update is called once per frame
    void FixedUpdate()
    {
        // jumping mechanic
        if (!isJumping)
        {
            rb.AddForce(jumppadForce * Vector3.up * Time.fixedDeltaTime, ForceMode.Impulse);
        }

        transform.Translate(Input.GetAxis("Vertical") * Time.deltaTime * MoveForce * Vector3.forward);
        transform.Translate(Input.GetAxis("Horizontal") * Time.deltaTime * MoveForce * Vector3.right);
    }
}
2

rb.AddForce takes in cosideration the previous force of the object, so if your player was been affected by some other force before the jump, it can changes your results a bit, for jumps instead of rb.AddForce(), try to direct set the velocity by rb.velocity = jumpForce; it will ignore any previous velocity.

Edit:
you may want to do it more like that rb.velocity = new Vector3(rb.velocity.x, jumpForce, rb.velocity.z); with that you can preserve your horizontal movement.

3

If i ready this correctly then your issue will not be solved by @DanielGL s solution.

Your force application in itself is probably correct but you do not consider that it might be applied multiple times as your condition to apply the force (!isJumping) is always true if a jumppad is in range of a raycast. If for some reason your player does not leave the raycast range in one fixed update you will add the force in the next frame as well which would lead to a doubled applied force.

So to solve this you should basically disable the possibility for force application for at least a few frames to make sure that you actually left the ground.