Unity Rigidbody2d jittering movement in the y-axis

Question

As said, rigidbody moves fine, even smoothly in the x axis.

Problem comes in on the y axis. Whenever the character goes up or down, it noticeably shakes.

Additional Info:

• Unity 5.6
• Using linear interpolation
• Mass is 5
• Linear Drag is 20
• Gravity is 0
• Angular Drag is 0
• Locked rotation on the z-axis
• Dynamic Rigidbody

• No parent Object, not even a child

  using System.Collections;
  using System.Collections.Generic;
  using UnityEngine;
  
  public class PlayerMovement : MonoBehaviour {
  
  Rigidbody2D rbody;
  //Animator anim;
  public float speed = 0;
  /*SpriteRenderer sr;
  Vector2 movementVector;
  void Start () {
      rbody = GetComponent<Rigidbody2D> ();
      anim = GetComponent<Animator> ();
      sr = GetComponent<SpriteRenderer>();
  }*/
  
  void Update(){
      //sr.sortingOrder = ((int)Camera.main.WorldToScreenPoint (sr.bounds.min).y) * -1;
      movementVector = new Vector2 ((Input.GetAxisRaw("Horizontal"))*3, Input.GetAxisRaw("Vertical"));
      /*if (movementVector != Vector2.zero) {
          anim.SetBool ("isWalking", true);
          anim.SetFloat ("inputX", movementVector.x);
          anim.SetFloat ("inputY", movementVector.y);
      } else 
          anim.SetBool ("isWalking", false);
  }*/
  
  void FixedUpdate(){     
      rbody.AddForce (movementVector * speed);
  }
  

  }

I also noticed that changing the mass and linear drag affected the movement speed on the y axis but not on the x axis, and movement on the y axis is noticeably faster than on the x axis, which is why I multiplied the horizontal input by 3.

Answer 1

Check to see if the rigidbody on your character has a gravity scale being applied to it;

That's my own guess for what's wrong. It's a common enough pitfall that I fall into every now and then myself, but it's a bit hard to tell without knowing what it looks like or what type of game you're doing.

On the code itself, I wouldn't recommend directly manipulating the Input, rather adjusting the input after getting it provides better insight as to whether the input itself is working.

...
// Let's divvy up the x and y speeds
public float xSpeed = 5;
public float ySpeed = 5;
Vector2 movementVector;

void Update(){
    ...
    movementVector = new Vector2 ((Input.GetAxisRaw("Horizontal")), Input.GetAxisRaw("Vertical"));
    ...
}

void FixedUpdate(){
    // Now we have more control for the x and y speeds, neato
    movementVector = new Vector2(movementVector.x * xSpeed, movementVector.y * ySpeed);
    rbody.AddForce (movementVector);
}

Answer 2

Fixed it!

For the varying speed at the axes:

1. Head over to Project Settings -> Input
2. Make sure gravity is 0 for both axes

For the camera, I tried to lock it and watch my character move around, and it moved without a jitter, my solution was:

1. Make sure that Camera's movement is under the same type of execution function as the target's movement is. So if target's at Update() then so should the camera.

Originally, my camera was at late update which must be why it jittered, because they were not moving at the same time.