Jump script using AddForce not working

Question

I am making a simple jump script by adding a separate script to the character.

I got the character from the Asset Store and I have left it untouched. I have searched the solution and similar problems to this, and I changed the force or JumpHeight to a pretty high value. But it is still nothing. The logs are printed out just fine.

public class JumpScript : MonoBehaviour {
public Rigidbody rb;
public float JumpHeight = 7.0f;

// Update is called once per frame
void Update () {
    if (Input.GetKeyDown (KeyCode.Space)) {
        Debug.Log ("PRESSSED");
        GetComponent<Rigidbody> ().AddForce (Vector3.up * JumpHeight);
        Debug.Log (GetComponent<Rigidbody> ());
    }
}

Answer 1

1. Be sure your character has a Rigidbody attached, and no Character Controller (if you're intending to move this character with physics)

2. Ensure the character's Rigidbody is set to dynamic, and its constraints allow movement on the y axis

3. Disallow rotation on the Rigidbody, to keep your character from tipping over accidentally

4. Verify that the character's collider is not interpenetrating with any scenery that might trap them in place

5. Use velocity changes or impulses to set velocity, not forces

---

Here's a simple jump script that helps fix a couple of these:

// This tells the editor to enforce "only use this script on objects with Rigidbodies".
[RequireComponent(typeof(Rigidbody))]
public class Jump : MonoBehaviour {

    public float jumpHeight 
    
    [SerializeField, HideInInspector]
    float _jumpVelocity;        
    [SerializeField, HideInInspector]
    Rigidbody _body;
    
    // When you tune the jump height in the inspector, automatically
    // calculate the physics values that will get you to that height.
    void OnValidate() {
        // Cache a reference to our body so we don't have to search at runtime.
        _body = GetComponent<Rigidbody>();
    
        // Solve v(t) = v(0) + a * t for v(t) = 0.
        float secondsToJumpApex = Mathf.Sqrt(-2f * jumpHeight / Physics.gravity.y);

        // Substitute into h(t) = h(0) + v(0) * t + (a/2) * t^2 and solve for v(0).
        _jumpVelocity = Physics.gravity.y * secondsToJumpApex; 
    }

    void Update() {
        // Use a named input set up in the Input Manager, not a hard-coded key.
        if (Input.GetButtonDown("Jump")) {
            // Jumps are instantaneous, so use VelocityChange instead of a gradual push.
            _body.AddForce(jumpVelocity * Vector3.up, ForceMode.VelocityChange);
        }
    }
}