Question Having Trouble with Jumps

Hello, I'm new to Unity and I'm having some trouble figuring out an issue.

I want so store if the player has pressed the space bar, even while in the air, so when it gets back in the ground, it jumps imediatelly.
The issue is that if the space bar was pressed mid-air, when the player touches the ground again, the section where i "AddForce" gets triggered, but the player just doesn't jump, the impulse doesn't get added at all.

Is anyone able to point out what i might be doing wrong?

Vidio demonstrating the issue:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using System.Timers;
4. using UnityEngine;
5.  
6. public class Player : MonoBehaviour
7. {
8.     [SerializeField] Transform GroundedCheck;
9.     [SerializeField] float Speed;
10.     [SerializeField] float JumpHeight;
11.     Vector3 V3Speed = new Vector3();
12.     Vector3 JumpVector;
13.     Rigidbody Rigidbody;
14.     bool SpacePressed;
15.  
16.     // Start is called before the first frame update
17.     void Start()
18.     {
19.         JumpVector.y = JumpHeight;
20.         Rigidbody = GetComponent<Rigidbody>();
21.     }
22.  
23.     // Update is called once per frame
24.     void Update()
25.     {
26.         //Check if space is pressed
27.         if (Input.GetKeyDown(KeyCode.Space))
28.         {
29.             SpacePressed = true;
30.             Debug.Log("Space Bar Pressed!");
31.         }
32.  
33.         V3Speed.x = Input.GetAxis("Horizontal") * Speed;
34.         V3Speed.z = Input.GetAxis("Vertical") * Speed;
35.     }
36.  
37.     private void FixedUpdate()
38.     {
39.         //Jump
40.         if (SpacePressed && IsGrounded())
41.         {
42.             Debug.Log($"IT SHOULD HAVE JUMPED!");
43.             Rigidbody.AddForce(JumpVector, ForceMode.Impulse);
44.             SpacePressed = false;
45.         }
46.  
47.         //Set Y Speed to current Y speed, so it doesnt get set to 0
48.         V3Speed.y = Rigidbody.velocity.y;
49.  
50.  
51.         Rigidbody.velocity = V3Speed;
52.     }
53.  
54.     bool IsGrounded()
55.     {
56.         //GroundCheck is set at the exact feet of the player, so radius can actually be 0
57.         return Physics.OverlapSphere(GroundedCheck.position, 0.0f).Length > 1;
58.     }
59. }
60.  

 

The issue would be due to the fact your rigid body has downward velocity at the time of landing with space still pressed, which is most likely overriding the upwards force you apply. Or more accurately, the two forces are just roughly cancelling each other out (Newtons third law).

You should get the results you want if you use ForceMode.VelocityChange in the second parameter of your AddForce call. This will just 'set' the velocity based on the force, ignoring it's current motion.

 

Hey,
I tried making the changes you suggested, at line 43, but the exact same issue is still present, no change at all.

 

I was able to fix it by manually setting the Y velocity to 0 right before the Jump

Code (CSharp):

1. if (SpacePressed && IsGrounded())
2.         {
3.             Rigidbody.velocity = new Vector3(Rigidbody.velocity.x, 0, Rigidbody.velocity.z);
4.             Rigidbody.AddForce(JumpVector, ForceMode.VelocityChange);
5.             SpacePressed = false;
6.         }