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Stuck in walls using a Rigidbody Movement Unity 3D

I am in the process of creating movement for my player that can only move on the x and y axis, I decided to make it a 3D game because I've been trying to learn that dimension of games. My movement functions are set up as so:
public void playerMovement()
{
horizontalInput = (int)Input.GetAxisRaw("Horizontal");
if (horizontalInput != 0)
{
moveX = Mathf.MoveTowards(moveX, horizontalInput * speed, Time.deltaTime * acceleration);
} else
{
moveX = Mathf.MoveTowards(moveX, horizontalInput * speed, Time.deltaTime * acceleration * 4f);
}
rb.velocity = new Vector3(moveX, rb.velocity.y, 0);
grounded = Physics.CheckSphere(groundCheck.transform.position, .2f, LayerMask.GetMask("Ground"));
if (Input.GetKeyDown(KeyCode.UpArrow))
{
Jump();
}
}
public void Jump()
{
if (grounded)
{
rb.velocity = new Vector3(rb.velocity.x, jumpSpeed, 0);
}
}
I am using this code from a tutorial I found on Tiktok and everything works well in the update function, however, when I collide with a wall or the side of any of my objects, I stop in place and can't fall back down. I also can't move out of the area very fast, it takes about 3 seconds to move out of there(I predict from my acceleration slowing down and turning around).
Is there a reason I am stuck on the wall once I collide?

How to realistically reflect a 3d sphere in Unity with C#

I've been trying to realistically reflect a 3d sphere on the walls of a box for a while now in Unity. For some reason, the reflection is generally correct, but when the ball hits a wall in certain directions, the reflection is incorrect.
To illustrate what happens to the ball upon hitting a wall: T = top wall, R = right wall, L = left wall, and B = bottom wall. Let r = the ball comes/goes to the right, l = for the left, and s = the ball stops/slows down significantly. The instructions below take this format: Xyz, where X = the wall the ball is about to hit, y = the ball's initial direction, z = the reflection. The game has a top-down perspective, and the instructions are based on the wall's perspective. I'm also new to C#, so the code is potentially eye burning.
Instructions: Tll, Trl; Bll, Brl; Rls or after hitting another wall Rlr, Rrl; Lls or after hitting another wall Llr, Lrl
Generally, when the ball stops, it jumps in the air. I wonder if this is because the angle reflects along the wrong axis, but why would this only sometimes happen? Also, when only one key is held, the ball bounces back and forth until it leaves the arena. I know about discrete and continuous hit detection, and the setting is on discrete, but the walls generally contain the ball well enough, with this case being the exception.
What I tried:
Figuring out how to use Vector3.Reflect. I do not understand what variables this function should contain and how to apply this to my code. I did look at the Unity Documentation page for help, but it did not answer my question.
Changing the negative signs, as the angle has to be a reflection on the y-axis, and this does change how the reflections work, but does not solve the problem. The current way the negatives are ordered are the most ideal I found.
Giving the ball a physics material for bounciness.
Adding a small number to the denominator in the arctan equation to help prevent a division by zero. This did not help at all.
Creating different equations (basically changing the negatives) for varying combinations of positive and negative accelerations. Since there is a certain positive or negative acceleration associated with each button press (see Movement script), and there seems to be an issue with said signs, I wondered if associating each acceleration with its own set of equations could solve the problem. It did not work.
Checked if the walls were at different angles.
Deleting the variables xA and yA, or placing them in different spots.
Experimented with finding the speed of the object, but had no idea how to implement it.
The code for the Movement script for the player named Controller:
public class Movement : MonoBehaviour
{
public static float xAcceleration = 0.0f;
public static float yAcceleration = 0.0f;
// Update is called once per frame
void Update()
{
if (Input.GetKey(KeyCode.W)) //If the key W is pressed:
{
Vector3 position = this.transform.position; //Variable position is set to transform the players placement in the game.
if (yAcceleration >= -5 && yAcceleration <= 5) //If the y vector of the acceleration is >= -5 and <= 5:
{
yAcceleration = yAcceleration + 0.01f; //The y vector of the acceleration increases by 0.01 as long as the key W is pressed.
}
position.z = position.z + (0.1f * yAcceleration); //The position of the object on the z-axis (pretend it is the y-axis in the game world) is transformed by its original position plus its speed times its yAcceleration.
this.transform.position = position; //The gameObject is now transformed to a position equal to the variable position by the z-axis.
}
else //If the key W is let go of:
{
Vector3 position = this.transform.position;
position.z = position.z + (0.1f * yAcceleration);
this.transform.position = position; //The position of the gameObject continues to update, but its acceleration does not change. Basically, it continues to move forward.
}
//The rest of the code is very similar to the above, but I included it just in case there was something wrong.
if (Input.GetKey(KeyCode.S))
{
Vector3 position = this.transform.position;
if (yAcceleration >= -5 && yAcceleration <= 5)
{
yAcceleration = (yAcceleration) - 0.01f;
}
position.z = position.z + (0.1f * yAcceleration);
this.transform.position = position;
}
else
{
Vector3 position = this.transform.position;
position.z = position.z + (0.1f * yAcceleration);
this.transform.position = position;
}
if (Input.GetKey(KeyCode.A))
{
Vector3 position = this.transform.position;
if (xAcceleration >= -5 && xAcceleration <= 5)
{
xAcceleration = (xAcceleration) - 0.01f;
}
position.x = position.x + (0.1f * xAcceleration);
this.transform.position = position;
}
else
{
Vector3 position = this.transform.position;
position.x = position.x + (0.1f * xAcceleration);
this.transform.position = position;
}
if (Input.GetKey(KeyCode.D))
{
Vector3 position = this.transform.position;
if (xAcceleration >= -5 && xAcceleration <= 5)
{
xAcceleration = (xAcceleration) + 0.01f;
}
position.x = position.x + (0.1f * xAcceleration);
this.transform.position = position;
}
else
{
Vector3 position = this.transform.position;
position.x = position.x + (0.1f * xAcceleration);
this.transform.position = position;
}
}
}
This is the code for the collider and reflection:
public class Collider : MonoBehaviour
{
public float xA;
public float yA;
void OnCollisionEnter(Collision collision) //If a gameObject enters the collision of another object, this immediately happens once.
{
if (gameObject.tag == "Boundary") //If the gameObject has a tag named Boundary:
{
yA = -Movement.yAcceleration; //yA stores the value of yAcceleration after being called from script Movement as a negative. Its a reflection.
Movement.xAcceleration = (Movement.xAcceleration * -Mathf.Atan(yA / Movement.xAcceleration)); //xAcceleration is changed based on this equation: A * artan(A_y / A_x). The 0.000001 was here, adding to A_x to help prevent a 0 as the denominator.
xA = Movement.xAcceleration; //This is declared now...
Movement.yAcceleration = (Movement.yAcceleration * Mathf.Atan(Movement.yAcceleration / xA)); //This uses xA because Movement.xAcceleration is changed, and the yAcceleration calculation is based on the xAcceleration prior the collision.
}
}
void OnCollisionStay(Collision collision)
{
if (gameObject.tag == "Boundary")
{
yA = Movement.yAcceleration; //The same thing happens as before.
Movement.xAcceleration = (Movement.xAcceleration * -Mathf.Atan(yA / Movement.xAcceleration));
xA = Movement.xAcceleration;
Movement.yAcceleration = (Movement.yAcceleration * Mathf.Atan(Movement.yAcceleration / xA));
Movement.xAcceleration = -Movement.xAcceleration / 2; //On collision, the ball is reflected across the x-axis at half its speed.
Movement.yAcceleration = Movement.yAcceleration / 2; //yAcceleration is half its original value.
}
}
}
The picture below is the game setup. I apologize that it is a link; I do not have enough Reputation to merit a loaded image on this page. Also, if anything is unclear, please message me.
https://i.stack.imgur.com/VREV4.png
I would really appreciate the help. Thanks!

One very important note here: As soon as there is any Rigidbody involved you do not want to set any values through the .transform - This breaks the physics and collision detection!
Your Movement should rather alter the behavior of the Rigidbody e.g. by simply changing its Rigibody.velocity
I would then also place the collision check directly into the balls's component and check whether you hit a wall ("Boundary")
Then another note: Your code is currently frame-rate dependent. It means that if your target device runs with only 30 frames per second you will add 0.3 per second to the acceleration. If you run however on a more powerful device that manages to run with 200 frames per second then you add 2 per second.
You should rather define the de/increase per second and multiply it by Time.deltaTime
All together maybe something like this
public class Movement : MonoBehaviour
{
// Adjust these settings via the Inspector
[SerializeField] private float _maxMoveSpeed = 5f;
[SerializeField] private float _speedIncreasePerSecond = 1f;
// Already reference this via the Inspector
[SerializeField] private Rigidbody _rigidbody;
private void Awake()
{
if(!_rigidbody) _rigidbody = GetComponent<Rigidbody>();
}
// Get User Input in Update
private void Update()
{
var velocity = _rigidbody.velocity;
velocity.y = 0;
if (Input.GetKey(KeyCode.W) && velocity.z < _maxMoveSpeed)
{
velocity.z += _speedIncreasePerSecond * Time.deltaTime;
}
if (Input.GetKey(KeyCode.S) && velocity.z > -_maxMoveSpeed)
{
velocity.z -= _speedIncreasePerSecond * Time.deltaTime;
}
if (Input.GetKey(KeyCode.A) && velocity.x > -_maxMoveSpeed)
{
velocity.x -= _speedIncreasePerSecond * Time.deltaTime;
}
if (Input.GetKey(KeyCode.D) && velocity.x < _maxMoveSpeed)
{
velocity.x += _speedIncreasePerSecond * Time.deltaTime;
}
// clamp to the max speed in case you move diagonal
if(velocity.magnitude > _maxMoveSpeed)
{
velocity = velocity.normalized * _maxMoveSpeed;
}
_rigidbody.velocity = velocity;
}
}
And then finally simply add a PhysicsMaterial with desired settings to the walls and ball.
I used Friction = 0f and Bounciness = 0.7f for ball and walls. For slow movements you also might want/have to adjust the Bounce Threshold in the Project's Physics Settings otherwise there will be no bouncing if the velocity is smaller then 2 by default.
This depends a bit on your definition of "realistic". I disabled gravity so the ball also has no rotation and angular friction:

Dash against slopes using physics in Unity 2D

I'm working on a 2D project in Unity.
The character controller is physics based, so I use rigidbody to move the player. Everything is working fine except when I try to apply a high speed movement to the character, like a dash.
This is how the code looks like.
I just check if the player is dashing, so I increase the Vector2 movement in a certain amount.
private void DashMovement() {
if (isDashing) {
movement.x *= dashFactor;
}
}
I'm also calculating the ground angle, so I set the movement vector to follow the ground inclination.
private void OnSlopeMovement() {
if (isGrounded && !isJumping) {
float moveDistance = Mathf.Abs(movement.x);
float horizontalOnSlope = Mathf.Cos(groundAngle * Mathf.Deg2Rad) * moveDistance * Mathf.Sign(movement.x);
float verticalOnSlope = Mathf.Sin(groundAngle * Mathf.Deg2Rad) * moveDistance;
if (horizontalOnSlope != 0)
movement.x = horizontalOnSlope;
if (isGrounded && verticalOnSlope != 0)
movement.y = verticalOnSlope;
}
SetMaxFallVelocity();
}
So I set the rigidbody velocity for making it move.
private void Move() {
movement.x *= Time.fixedDeltaTime;
if(isGrounded && !isJumping) movement.y *= Time.fixedDeltaTime;
Vector3 targetVelocity = new Vector2(movement.x, movement.y);
PlayerController.rb2d.velocity = Vector3.SmoothDamp(PlayerController.rb2d.velocity, targetVelocity, ref velocity, movementSmoothing);
}
The problem appears when I apply a speed high enough. I understand this issue is because of physics.
I think the ray that checks the ground and is used to calculate the groundAngle doesn't work fast enough to keep track of that movement, so I can not keep the player fixed on the ground.
I would like to find a solution without making the player kinematic, or stopping the dash on slopes.
This is how it looks ingame.
And this is how the rigidbody movement remain right over the ground, following the slopes angle.
EDIT:
This is how I get the ground angle:
private void GroundAngle() {
Vector2 rayOrigin = feetCollider.bounds.center;
rayOrigin.y += 0.1f;
Vector2 rayDirection = (Input.GetAxisRaw("Horizontal") == 0) ? Vector2.right : new Vector2(Input.GetAxisRaw("Horizontal"), 0);
int groundCollisions = Physics2D.RaycastNonAlloc(rayOrigin, Vector2.down, groundResults, Mathf.Infinity, groundMask);
if (groundCollisions > 0) {
groundAngle = Vector2.Angle(groundResults[0].normal, rayDirection) - 90f;
//Debug.DrawRay(rayOrigin, Vector2.down, Color.green);
if (groundAngle > 0 && !isDashing) {
rayOrigin.x += Input.GetAxisRaw("Horizontal") * .125f;
Physics2D.RaycastNonAlloc(rayOrigin, Vector2.down, groundResults, Mathf.Infinity, groundMask);
groundAngle = Vector2.Angle(groundResults[0].normal, rayDirection) - 90f;
//Debug.DrawRay(rayOrigin, Vector2.down, Color.blue);
}
}
}
Thanks to #Ruzhim for the help. I just post a first "solution" for the problem.
According to Ruzhim advises, I've used him code this way.
private void SetPositionAfterTick() {
if (isDashMovement) {
Vector2 currentPosition = new Vector2(transform.position.x, transform.position.y);
currentPosition.y = feetCollider.bounds.min.y;
Vector2 feetPosAfterTick = currentPosition + PlayerController.rb2d.velocity * Time.deltaTime;
float maxFloorCheckDist = .1f;
RaycastHit2D groundCheckAfterTick = Physics2D.Raycast(feetPosAfterTick + Vector2.up * maxFloorCheckDist, Vector2.down, maxFloorCheckDist * 5f);
if (groundCheckAfterTick) {
Vector2 wantedFeetPosAfterTick = groundCheckAfterTick.point;
if (wantedFeetPosAfterTick != feetPosAfterTick) {
//PlayerController.rb2d.transform.position = (wantedFeetPosAfterTick + new Vector2(0f, feetCollider.bounds.min.y - PlayerController.rb2d.position.y));
PlayerController.rb2d.velocity = Vector2.zero;
}
}
}
}
This is how it looks like.
This is good enough to continue polishing that mechanic. I still need to set the position in some way. The rigidbody's position calculation is not working as it
is raised right now, as the condition (wantedFeetPosAfterTick != feetPosAfterTick) is always true, so the character goes throw the floor and fall.
As you can see, I also need to control the down slopes movement, as it uses the slopes movement sometimes, and dash straight forward others.

This is how asker Rubzero implemented the below code to work for them:
private void SetPositionAfterTick() {
if (isDashMovement) {
Vector2 currentPosition = new Vector2(transform.position.x, transform.position.y);
currentPosition.y = feetCollider.bounds.min.y;
Vector2 feetPosAfterTick = currentPosition + PlayerController.rb2d.velocity * Time.deltaTime;
float maxFloorCheckDist = .1f;
RaycastHit2D groundCheckAfterTick = Physics2D.Raycast(feetPosAfterTick + Vector2.up * maxFloorCheckDist,
Vector2.down, maxFloorCheckDist * 5f);
if (groundCheckAfterTick) {
Vector2 wantedFeetPosAfterTick = groundCheckAfterTick.point;
if (wantedFeetPosAfterTick != feetPosAfterTick) {
//PlayerController.rb2d.transform.position = (wantedFeetPosAfterTick + new Vector2(0f, feetCollider.bounds.min.y -
PlayerController.rb2d.position.y));
PlayerController.rb2d.velocity = Vector2.zero;
}
}
}
}
This is how it looks like.
This is good enough to continue polishing that mechanic. I still need
to set the position in some way. The rigidbody's position calculation
is not working as it is raised right now, as the condition
(wantedFeetPosAfterTick != feetPosAfterTick) is always true, so the
character goes throw the floor and fall.
As you can see, I need to control the down slopes movement, as it uses
the slopes movement sometimes, and dash straight forward others.
I agree with AresCaelum; using physics to do slope movement is pretty much the opposite of what you want to be doing if you don't want to preserve momentum when you're done going up/down the slope. Specifically, your problem is here:
float moveDistance = Mathf.Abs(movement.x);
float horizontalOnSlope = Mathf.Cos(groundAngle * Mathf.Deg2Rad) * moveDistance * Mathf.Sign(movement.x);
float verticalOnSlope = Mathf.Sin(groundAngle * Mathf.Deg2Rad) * moveDistance;
This is a problem because the more the player moves horizontally in a frame, the more they will move vertically based on the slope of the ramp they are on. However, this assumption doesn't hold if they should only be traveling up the ramp during only part of the movement during the frame. So, you need a way to handle that situation.
One solution is to use a raycast from where the player would be then if it's above the floor, alter the vertical velocity so that it would place them at that floor's position instead.
First, determine if slope movement has occurred in a physics frame...
private bool slopeMovementOccurred = false;
void FixedUpdate() {
slopeMovementOccurred = false;
// ...
}
private void OnSlopeMovement() {
if (isGrounded && !isJumping) {
slopeMovementOccurred = true;
// ...
}
SetMaxFallVelocity();
}
... and if it has, determine where the player is going to be after the physics update. Then do a physics2d raycast from above that position (by some amount) downward (double the previous amount) to find where the player's position should be, and then change the rb2d.velocity such that it will place the player exactly at the height they should be at.
Assuming you can calculate some kind of Vector2 feetOffset that has the local position of the player's feet:
void FixedUpdate() {
// ...
StickToSlopeLanding();
}
void StickToSlopeLanding() {
if (slopeMovementOccurred) {
Vector2 curVelocity = PlayerController.rb2d.velocity;
Vector2 feetPosAfterTick = PlayerController.transform.position
+ PlayerController.feetOffset
+ curVelocity * Time.deltaTime;
float maxFloorCheckDist = 1.0f;
// determine where the player should "land" after this frame
RaycastHit2D groundCheckAfterTick = Physics2D.Raycast(
feetPosAfterTick + Vector2.up * maxFloorCheckDist,
-Vector2.up, maxFloorCheckDist * 2f);
if (groundCheckAfterTick.collider != null) {
Vector2 wantedFeetPosAfterTick = groundCheckAfterTick.point;
// if basic physics won't take them to landing position
if (wantedFeetPosAfterTick != feetPosAfterTick) {
Vector2 wantedVelocity = curVelocity
+ Vector2.up
* ((wantedFeetPosAfterTick.y - feetPosAfterTick.y)
/ Time.deltaTime);
// adjust velocity so that physics will take them to landing position
PlayerController.rb2d.velocity = wantedVelocity;
// optionally, set a flag so that next frame
// it knows the player should be grounded
}
}
}
}
Hopefully this gets you towards a solution that will work.
Note: you may need to also move the rigidbody so that it doesn't try to clip through the corner at the top of the ramp, and you can determine where to put the rigidbody using another raycast, setting the velocity from that point to be horizontal:
void StickToSlopeLanding() {
if (slopeMovementOccurred) {
Vector2 curVelocity = PlayerController.rb2d.velocity;
Vector2 feetPosAfterTick = PlayerController.transform.position
+ PlayerController.feetOffset
+ curVelocity * Time.deltaTime;
float maxFloorCheckDist = 1.0f;
// determine where the player should "land" after this frame
RaycastHit2D groundCheckAfterTick = Physics2D.Raycast(
feetPosAfterTick + Vector2.up * maxFloorCheckDist,
-Vector2.up, maxFloorCheckDist * 2f);
if (groundCheckAfterTick.collider != null) {
Vector2 wantedFeetPosAfterTick = groundCheckAfterTick.point;
// if basic physics won't take them to landing position
if (wantedFeetPosAfterTick != feetPosAfterTick) {
// look for corner of ramp+landing.
// Offsets ensure we don't raycast from inside/above it
float floorCheckOffsetHeight = 0.01f;
float floorCheckOffsetWidth = 0.5f;
RaycastHit2D rampCornerCheck = Physics2D.Raycast(
wantedFeetPosAfterTick
- floorCheckOffsetHeight * Vector2.up
- floorCheckOffsetWidth * Mathf.Sign(movement.x) * Vector2.right,
Mathf.Sign(movement.x) * Vector2.right);
if (rampCornerCheck.collider != null) {
// put feet at x=corner position
Vector2 cornerPos = Vector2(rampCornerCheck.point.x,
wantedFeetPosAfterTick.y);
PlayerController.rb2d.position = cornerPos
- PlayerController.feetOffset;
// adjust velocity so that physics will take them from corner
// to landing position
Vector2 wantedVelocity = (wantedFeetPosAfterTick - cornerPos)
/ Time.deltaTime;
PlayerController.rb2d.velocity = wantedVelocity;
// optionally, set a flag so that next frame
// it knows the player should be grounded
}
}
}
}
}

Unity 3d - player is moving constantly after touching a wall

After my player object touches the wall it sometimes starts to move and rotate on it's own. I tried to increase player object weight and it helps, but i don't think it's a good approach as tiny movement never dissapears.
Player is rigidbody with box collider attached.
isKinematic - false;
useGravity - true;
XYZ rotation is fixed and Y coordinate position is fixed.
Walls have box collider but have no rigidbody.
Ground has no collider as Y position is fixed and player object doesn't touch the ground.
Game is network based so i have photon rigidbody view component attached to player as well.
Code (C#) which moves player:
public void Update()
{
if (!photonView.IsMine || !controllable)
{
return;
}
if (shootingTimer > 0.0)
{
shootingTimer -= Time.deltaTime;
}
m_MovementInputValue = Input.GetAxis(m_MovementAxisName);
if (m_MovementInputValue == 0.0f)
{
m_MovementInputValue = joystick.Vertical;
}
m_TurnInputValue = Input.GetAxis(m_TurnAxisName);
if (m_TurnInputValue == 0.0f)
{
m_TurnInputValue = joystick.Horizontal;
}
Vector3 vector = new Vector3(
m_TurnInputValue,
rigidbody.velocity.y,
m_MovementInputValue
);
MovementVector = Quaternion.AngleAxis(60, Vector3.up) * vector;
EngineAudio();
}
public void FixedUpdate()
{
if (!photonView.IsMine || !controllable)
{
return;
}
Move();
Turn();
}
private void Move()
{
// Adjust the position of the tank based on the player's input.
// Vector3 movement = transform.forward * m_MovementInputValue * m_Speed * Time.deltaTime;
// rigidbody.MovePosition(rigidbody.position + movement);
Vector3 movement = MovementVector * m_Speed * Time.deltaTime;
rigidbody.MovePosition(rigidbody.position + movement);
}
private void Turn()
{
// Adjust the rotation of the tank based on the player's input.
// float turn = m_TurnInputValue * m_TurnSpeed * Time.deltaTime;
// Quaternion turnRotation = Quaternion.Euler(0f, turn, 0f);
// rigidbody.MoveRotation(rigidbody.rotation * turnRotation);
if (m_TurnInputValue != 0.0f || m_MovementInputValue != 0.0f)
{
rigidbody.rotation = Quaternion.LookRotation(MovementVector);
}
}

Check to make sure the component (such as a rigidbody) is attached to the right object (gameobject - parent vs. child objects). Also, the fact that it is constantly rotating is curious... it makes me think it has something to do with the Time.DeltaTime, but I see that's only being applied to your Vector3 movement, and not in your rotation function... Just curious, what happens when you remove the Time.DeltaTime part from your movement Vector3?

Unity 5: How to slow down rigidbody naturally instead of sudden stop

I'm using this:
void Update(){
if(leftJoystick){
rb.AddRelativeForce(0, 0, 400f, ForceMode.Impulse);
}
}
to move my character forward in the air (using jetpack). When I let go of the joystick my character stops immediately. What I want is that the character keeps moving forward after joystick is released and with time slow down and gradually stop. It looks stupid that my character stops like it hit a wall. What kind of force/velocity/transform I should use so that physics slow down my character after I let go of the joystick?
My rigidbody settings:
Mass: 100
Drag: 0
Angular drag: 0.05
Uses gravity
Not kinematic
Interpolate: interpolate
Collision detection: Discrete
Freeze position: none
Freeze rotation: all
Character also has a capsule collider that is NOT trigger and has no physics material.
EDIT: here is the full code so you can see if there is any conflicts in my code
using UnityEngine;
using System.Collections;
using UnityStandardAssets.CrossPlatformInput;
public class JetpackController : MonoBehaviour{
Rigidbody rb;
// controller axes
[SerializeField]
public string speedAxis = "Vertical";
public string rotateAxis = "HorizontalRotate";
[SerializeField]
public float forwardSpeed;
public float upSpeed;
public float rotateSpeed;
public float rotationIgnoreZone;
public float MAX_HEIGHT;
float speedInput;
float rotateInput;
public bool leftJoystick;
public bool rightJoystick;
ParticleSystem jetpackFire1;
Vector3 originalGravity;
// access Joystick script in Standard assets to detect when right joystick is held down
Joystick joystick_left;
Joystick joystick_right;
void Start () {
if (GetComponent<Rigidbody> ()) {
rb = GetComponent<Rigidbody> ();
} else {
Debug.LogError ("Player needs to have a rigidbody.");
}
// get Joysticks
if (GameObject.Find ("MobileJoystick_left").GetComponent<Joystick> ()) {
joystick_left = GameObject.Find ("MobileJoystick_left").GetComponent<Joystick> ();
} else {
Debug.LogError ("Either gameobject with name 'MobileJoystick_right' does not exist in the scene or it does not have script called Joystick.cs attached to it.");
}
if (GameObject.Find ("MobileJoystick_right").GetComponent<Joystick> ()) {
joystick_right = GameObject.Find ("MobileJoystick_right").GetComponent<Joystick> ();
} else {
Debug.LogError ("Either gameobject with name 'MobileJoystick_right' does not exist in the scene or it does not have script called Joystick.cs attached to it.");
}
jetpackFire1 = GameObject.Find("JetpackFire1").GetComponent<ParticleSystem> ();
jetpackFire1.playbackSpeed = 5.0f;
originalGravity = Physics.gravity;
}
void FixedUpdate () {
GetInput ();
// move forward and backward according to left joysticks input
if(leftJoystick){
// left joystick held down
rb.AddRelativeForce(0, 0, forwardSpeed*speedInput, ForceMode.Impulse);
}
// if right joystick is used
if (rightJoystick) {
jetpackFire1.Play ();
if (transform.position.y < MAX_HEIGHT) {
// allow going up
//rb.AddRelativeForce (0, upSpeed, 0, ForceMode.Impulse);
rb.AddForce(transform.forward * forwardSpeed);
} else if (transform.position.y >= MAX_HEIGHT) {
// prevent player to go any further up and also falling
Physics.gravity = Vector3.zero; // no gravity to prevent player from falling
rb.velocity = Vector3.zero;
}
// rotate
// always keep rotating (player can go past look at joystick dir)
if (rotateInput >= rotationIgnoreZone || rotateInput <= -rotationIgnoreZone) {
transform.Rotate(Vector3.up * rotateInput, Time.deltaTime * rotateSpeed);
}
} else {
jetpackFire1.Stop ();
// if right joystick is released
Physics.gravity = originalGravity; // normal gravity -> player can fall
}
}
public void GetInput(){
speedInput = CrossPlatformInputManager.GetAxis (speedAxis);
rotateInput = CrossPlatformInputManager.GetAxis (rotateAxis);
// access Joystick.cs script to grab wether right joystick is pressed or not
leftJoystick = joystick_left.leftJoystickPressed;
rightJoystick = joystick_right.rightJoystickPressed;
}
}

Can't comment yet
Like J.Small said, you could multiply the velocity with a number around 0.95 to slowly slow the rigidbody down. If you put the multiplication in the Update method I suggest you to multiply the ~0.95 number with Time.deltaTime, so the velocity decrease will be proportional to the passed time.
void Update(){
if(leftJoystick){
rb.AddRelativeForce(0, 0, 400f, ForceMode.Impulse);
}
if(noJoystick){
rb.velocity = rb.velocity * 0.95 * Time.deltaTime;
//Or: rb.velocity.x
}
}
You could also apply a small amount of force instead of multiplying the velocity if you want to slow down the rigidbody in a more configurable way (the amount should be based on Time.deltaTime if you put it into Update - which gets called once a frame), but the method above is easier.

I'm not a pro at coding, so I'm not sure if this'll work for everyone, but I tried something like this to fix a similar issue.
void FixedUpdate()
{
playerRigidbody.AddRelativeForce(Vector2.up * forwardInput * playerSpeed * Time.fixedDeltaTime);
if (forwardInput <= 0)
{
playerRigidbody.velocity = playerRigidbody.velocity / 1.005f; // <-- This will gradually slow down the player when they're idle.
}
}

You could do a simple linear slow down.
void Update(){
if(leftJoystick){
rb.AddRelativeForce(0, 0, 400f, ForceMode.Impulse);
}
if(noJoystick){
rb.velocity = rb.velocity * 0.9;
}
}
Note that the update function gets called on frame update, so I would suggest putting this in a FixedUpdate() function that way the slow rate won't depend on the frame rate.