Gravity trouble: Falling slow, jumping fast

Question

I'm a noob so go easy on me.

I'm trying to make a simple jump function. Unfortunately, I go up very quickly and come down very slowly. Code is this:

 void FixedUpdate()
 {
     float moveHorizontal = Input.GetAxis("Horizontal");
     float moveVertical = Input.GetAxis("Vertical");
     Vector3 movement = new Vector3(moveHorizontal, 0.0F, moveVertical);

 //Note I'm not adding anything to the y vector here ^

  rb.velocity = movement * speed;

     if (Input.GetKey("space") && detectGround())
     {
         rb.AddForce(0.0F, 1000, 0.0F);

 //It seems like I'm adding way too much force on y vector, but even with that much I barely leave the ground. I need, like, 10,000 to get a good high jump.
   
     }
 }

 bool detectGround()
 {
     Vector3 down = transform.TransformDirection(Vector3.down);
     return Physics.Raycast(transform.position, down, .51F);
 }

I'm aware that I might run into weird gravity problems if I'm using odd scales, but I'm dealing with a 1x1x1 sphere in this case. Drag is also not the problem (and if it was, why do I go up so fast?). I've also tried adding some weight to my gravity by changing my y vector. That makes me fall faster but doesn't help the jump any.

Interestingly, I don't seem to have this problem if I use rb.AddForce(movement*speed) instead of rb.velocity = movement*speed. Then, however, I don't get the tight control that I want for my X axis and Z axis. (I accelerate too slowly, never hit a peak speed, and have trouble stopping).

How do I fix this?

Answer 1

Best Answer

Answer by NoseKills · Feb 07, 2017 at 04:38 PM

The problem should be here

 Vector3 movement = new Vector3(moveHorizontal, 0.0F, moveVertical);
 rb.velocity = movement * speed;

Adding a force to a rigidbody changes its velocity but that velocity only applies for 1 FixedUpdate because you specifically set the velocity.y component to 0 every FixedUpdate. Adding a huge force works because that causes velocity to change a lot so your character ends up high in the air in one FixedUpdate before you override the velocity again.

The solution is not to change the velocity.y.

 Vector3 movement = new Vector3(moveHorizontal, 0.0F, moveVertical)  * speed;
 movement.y = rb.velocity.y;
 rb.velocity = movement;

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smpkr · Feb 01, 2021 at 10:12 PM 0

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thanks this solved my issue! To any that follow make sure rb.velocity=movement comes after movement.y = rb.velocity.y.

Kristiyan_19 · Feb 08 at 10:23 AM 0

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what if I am not using velocity but AddForce instead ?

Gravity trouble: Falling slow, jumping fast

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