Develop Reference

Rigidbody.MovePosition() behaving strangely

using UnityEngine;
public class ThirdPersonMovement : MonoBehaviour
{
Rigidbody rb;
private Animator animator;
public float speed = 5f;
void Start() {
animator = GetComponent<Animator>();
rb = GetComponent<Rigidbody>();
}
// Update is called once per frame
void Update()
{
//Get player input based on world space.
float playerHorizontalInput = Input.GetAxisRaw("Horizontal");
float playerVerticalInput = Input.GetAxisRaw("Vertical");
//Get camera-normalized directional vectors
Vector3 forward = Camera.main.transform.forward;
Vector3 right = Camera.main.transform.right;
//Create direction-relative input vectors
Vector3 forwardRelativeVerticalInput = playerVerticalInput * forward;
Vector3 rightRelativeHorizontalInput = playerHorizontalInput * right;
Vector3 cameraRelativeMovement = forwardRelativeVerticalInput + rightRelativeHorizontalInput;
Vector3 movement = cameraRelativeMovement * speed * Time.deltaTime;
rb.MovePosition(transform.position + movement);
transform.forward = cameraRelativeMovement;
if (cameraRelativeMovement != Vector3.zero)
{
animator.SetBool("IsMoving", true);
}
else {
animator.SetBool("IsMoving", false);
}
}
}
I know similar questions have been posted before but I haven't been able to find a solution to what I'm experiencing.
I have the code above and it is linked to a character with a rigidbody component and 'is kinematic' checked. When I try to move, the character doesn't move for ages and then randomly jumps forward a random distance and doesn't do it again until I hit W again.
This has worked before when I used transform.Translate but obviously my character ran through the floor when the camera pointed down so I was trying to fix the issue.

A few things I notice about your code. You said this method used to work with transform.translate but not anymore, this tells me that your movement vectors are probably fine up until the point you changed them for this implementation (my guess is everything is the same except when you added tranform.position to your vector, since the function doesn't take speed, it takes position). You could try testing tranform.position + movement or just movement with a Debug.Log() statement, but that's probably not your issue.
Since you said this issue only started when you changed the function you use to move the player, I would try just inputting a non-changing Vector3 into the movement function: rb.movePosition(tranform.position + new Vector3(1,0,0)); or something like that, just to see if the movement function is even working.

Set rigidbody.velocity to direction of mouse in Unity2d: Updated Version

Yes I know this question was asked before by SuperSonyk! That post is here:
Set rigidbody.velocity to direction of mouse in Unity2d
However- the link referenced in the answer to that post is now legacy material, and I can't bring myself to understand it in Unity's current version.
My Problem: In short, I want to make my player accelerate in the direction of my cursor. My game is currently a TOP-DOWN Space Shooter in 2D. My player already looks at my mouse correctly, using cam.ScreenToWorldPoint. But relentlessly trying to add force seems futile for me, since I am fairly new to coding.
If I have any other issues in my code, It would be great if anyone could point them out!
Here's my code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour
{
//================= MOVEMENT =====================
private float thrust = 0.5f;
private float maxSpeed = 10f;
public Rigidbody2D rb;
//================= AIMING =======================
public Camera cam;
Vector2 mousePos;
// Update is called once per frame: Good for INPUTS
void Update()
{
//aiming
mousePos = cam.ScreenToWorldPoint(Input.mousePosition);
}
// Called Set amount of times. Good for PHYSICS CALCULATIONS
void FixedUpdate()
{
Move();
speedLimiter();
//aim
Vector2 lookDirection = mousePos - rb.position;
float angle = Mathf.Atan2(lookDirection.y, lookDirection.x) * Mathf.Rad2Deg - 90f;
rb.rotation = angle;
}
//======= MY MOVE FUNCTION DOES NOT WORK. HELP? ======
void Move()
{
if (Input.GetButtonDown("Accelerate"))
{
rb.velocity = new Vector3(0, thrust, 0) * Time.deltaTime;
}
}
void speedLimiter()
{
if (rb.velocity.magnitude > maxSpeed)
{
rb.velocity = Vector3.ClampMagnitude(rb.velocity, maxSpeed);
}
}
}
Please summarize the edits clearly, thank you!

In general since this is a 2D rigidbody also the velocity is a Vector2 and you should probably rather use Vector2.ClampMagnitude
and then in
rb.velocity = new Vector3(0, thrust, 0) * Time.deltaTime;
do you only want to move in global Y direction? Also a velocity is already a "per second" value -> it makes no sense to multiply by Time.deltaTime if you reassign a new velocity. Since it says thrust I guess you rather wanted to add to the existing velocity.
What you would rather do is save your mouse direction you already have and do
public class PlayerController : MonoBehaviour
{
...
void FixedUpdate()
{
// I would update the aim BEFORE moving
// Use a NORMALIZED direction! Makes things easier later
Vector2 moveDirection = (mousePos - rb.position).normalized;
float angle = Mathf.Atan2(moveDirection.y, moveDirection.x) * Mathf.Rad2Deg - 90f;
rb.rotation = angle;
// OPTIONAL: Redirect the existing velocity into the new up direction
// without this after rotating you would still continue to move into the same global direction
rb.velocity = rb.velocity.magnitude * moveDirection;
Move(moveDirection);
speedLimiter();
}
void Move(Vector2 moveDirection)
{
if (Input.GetButtonDown("Accelerate"))
{
// Instead of re-assigning you would probably add to the existing velocity
// otherwise remove the "+" again
rb.velocity += moveDirection * thrust * Time.deltaTime;
}
}
void speedLimiter()
{
if (rb.velocity.magnitude > maxSpeed)
{
// You are working with Vector2 so use the correct method right away
rb.velocity = Vector2.ClampMagnitude(rb.velocity, maxSpeed);
}
}
}

You already have half of the work by having your player looking at the mouse. We will be using the vector lookDirection as the direction of the movement for the player, normalize it so its length is 1 and multiply it by thrust. This way, we have a vector in the direction of the mouse and of length thrust as intended.
void Move()
{
if (Input.GetButtonDown("Accelerate"))
{
Vector2 lookDirection = (mousePos - rb.position);
rb.AddForce(lookDirection.normalized * thrust);
}
}
Note that we work here with Vector2 since you are using a Rigidbody2D.
Also, I don't think that using Time.DeltaTime is relevant here. When you apply force to a physic object, you don't need to use it, by definition, the function FixedUpdate() has a fixed frequency. If you look at one of Unity's tutorial, you can see that they don't multiply it by Time.DeltaTime
Last tip: you may want to be playing around with the drag property of your Rigidbody2D to have your player slow down over time when not accelerating, otherwise, it will be sliding out of control and the player won't be able to stop it.
Don't hesitate to tell me if my answer is not clear for you or does not entirely satisfy you, it's my first answer here!
EDIT: I forgot to tell you but as derHugo mentioned, since you are using Rigidbody2D, you must use Vector2.ClampMagnitude to limit your speed in your speedLimiter function. Also, I don't think that you need your if since the function Vector2.ClampMagnitude will only change the value of the velocity if it exceeds the maximum.

Thanks to everyone who responded!
With the help of Brackeys community, I managed to solve this by using this method:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour
{
//================= MOVEMENT =====================
private float thrust = 10f;
private float maxSpeed = 100f;
public Rigidbody2D rb;
//================= AIMING =======================
public Camera cam;
Vector2 mousePos;
// Update is called once per frame: Good for INPUTS
void Update()
{
//aiming
mousePos = cam.ScreenToWorldPoint(Input.mousePosition);
}
// Called Set amount of times. Good for PHYSICS CALCULATIONS
void FixedUpdate()
{
Move();
speedLimiter();
//aim
Vector2 lookDirection = mousePos - rb.position;
float angle = Mathf.Atan2(lookDirection.y, lookDirection.x) * Mathf.Rad2Deg - 90f;
rb.rotation = angle;
}
void Move()
{
if (Input.GetKey("up"))
{
rb.AddRelativeForce(Vector2.up*thrust);
}
}
void speedLimiter()
{
if (rb.velocity.magnitude > maxSpeed)
{
rb.velocity = Vector3.ClampMagnitude(rb.velocity, maxSpeed);
}
}
//rb.AddForce(new Vector3(0, thrust, 0));
}

My 2D Character is not jumping at all

I am having an issue with my character which is not jumping at all. I am new to Unity, but I made sure to apply the script to the player and adjust the speed, I did not touch the Rigidbody 2D. If any one can help me figure our the issue, it will be much appreciated.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerController : MonoBehaviour {
public float moveSpeed;
public float jumpSpeed;
public bool grounded = false;
private Rigidbody2D rb;
void Start() {
rb = GetComponent<Rigidbody2D>();
}
void Update () {
transform.Translate (Input.GetAxisRaw ("Horizontal") * moveSpeed * Time.deltaTime, 0, 0);
if (grounded)
{
if (Input.GetButtonDown ("Jump"))
{
rb.AddForce (Vector2.up * jumpSpeed);
grounded = false;
}
}
}
void OnCollisionEnter2D (Collision2D coll){
if (coll.transform.tag == "Ground")
{
grounded = true;
}
}
}
Inspector window of the Player GameObject
Inspector window of the Ground GameObject

Your problem is you haven't tag the Ground GameObject as so. So in the OnCollisionEnter2D the character detects the collision, but the if (coll.transform.tag == "Ground") will never be true. So it means the character can't be grounded
Since to be grounded is the first condition to check if the player pressed the Jump key. It is impossible it will ever jump
if (grounded)
{
if (Input.GetButtonDown ("Jump"))
{
rb.AddForce (Vector2.up * jumpSpeed);
grounded = false;
}
}
To solve this issue: You need to tag the Ground GameObject as so. In case you are not sure how to do that, on the Tag menu, create (if it doesnt exist already) a new tag called Ground. Then assign in that same menu the Ground Tag to the Ground GameObject. Here you can learn how in case you need a visual reference:
https://docs.unity3d.com/Manual/Tags.html
Edit: You can try this script if everything fails. It should work. I used my self some time ago, I cleaned the code so to leave only what you need to move the character in the x and y axis. Hope to have included everything you need:
public class CharacterController2D : MonoBehaviour {
// LayerMask to determine what is considered ground for the player
public LayerMask whatIsGround;
// Transform just below feet for checking if player is grounded
public Transform groundCheck;
// store references to components on the gameObject
Transform transform;
Rigidbody2D rigidbody;
bool isGrounded = false;
float vy;
float vx;
public float jumpForce = 600f;
void Awake () {
transform = GetComponent<Transform> ();
rigidbody = GetComponent<Rigidbody2D> ();
}
void Update()
{
// determine horizontal velocity change based on the horizontal input
vx = Input.GetAxisRaw ("Horizontal");
vy = rigidbody.velocity.y;
// Check to see if character is grounded by raycasting from the middle of the player
// down to the groundCheck position and see if collected with gameobjects on the
// whatIsGround layer
isGrounded = Physics2D.Linecast(transform.position, groundCheck.position, whatIsGround);
if(isGrounded && Input.GetButtonDown("Jump")) // If grounded AND jump button pressed, then allow the player to jump
{
DoJump();
}
// Change the actual velocity on the rigidbody
rigidbody.velocity = new Vector2(_vx * MoveSpeed, _vy);
}
//Make the player jump
void DoJump()
{
// reset current vertical motion to 0 prior to jump
vy = 0f;
// add a force in the up direction
rigidbody.AddForce (new Vector2 (0, jumpForce));
}
}
So things to take into account:
Instead of tag the ground, you create a layer with everything you
consider ground. That will include possible platforms the character
may jump over. Pass as a parameter this layer to the script in the
inspector
You need to place an empty GameObject in the feet of the character.
You will drag and drop that GameObject in the editor onto the
groundCheck public variable.
Instead of OnTriggerEnter, you will use Physics2D.Linecast which
will trave a line from the position of the character to under its
feet (where you should have place the Transform mentioned in the
previous step) and if in the middle there is an element of the
groundLayer, it means the character will be grounded.
Let me know if anything is not clear or if you find some bug.

As mentioned your problem is deffinetly that your missing to tag your ground object :)
A tip: What i like to do when i have problems like this is to use the unitys Debug.Log() to locate where the problem is it. It will let you know easily in the console what code is run and which is not. Try do the following:
void Update () {
transform.Translate (Input.GetAxisRaw ("Horizontal") * moveSpeed * Time.deltaTime, 0, 0);
if (grounded)
{
Debug.Log("Is grounded");
if (Input.GetButtonDown ("Jump"))
{
Debug.Log("Jump clicked");
rb.AddForce (Vector2.up * jumpSpeed);
grounded = false;
}
}
}

How do I make my player with a Rigidbody move with isKinematic checked?

My game is a topdown zombie shooter and whenever the zombies get to the player they bunch up underneath them, to the point where the player can just walk over the zombies. I noticed that when I check isKinematic on the Rigidbody the zombies cant push the player up to go underneath him, so they just run into him(which is what I want). Despite this I am then unable to move. How can i fix this?
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class PlayerMoving1 : MonoBehaviour {
public float moveSpeed;
private Rigidbody myRigidbody;
private Vector3 moveInput;
private Vector3 moveVelocity;
private Camera mainCamera;
public GunController theGun;
void Start () {
myRigidbody = GetComponent <Rigidbody>();
mainCamera = FindObjectOfType<Camera>();
}
// Update is called once per frame
void Update () {
moveInput = new Vector3(Input.GetAxisRaw("Horizontal"), 0f, Input.GetAxisRaw("Vertical"));
moveVelocity = moveInput * moveSpeed;
Ray cameraRay = mainCamera.ScreenPointToRay(Input.mousePosition);
Plane groundPlane = new Plane(Vector3.up, Vector3.zero);
float rayLength;
if(groundPlane.Raycast(cameraRay,out rayLength))
{
Vector3 pointToLook = cameraRay.GetPoint(rayLength);
transform.LookAt(new Vector3(pointToLook.x,transform.position.y,pointToLook.z));
}
if (Input.GetMouseButtonDown(0))
theGun.isFiring = true;
if (Input.GetMouseButtonUp(0))
theGun.isFiring = false;
}
void FixedUpdate(){
myRigidbody.velocity = moveVelocity;
}
}

With isKinematic == true You can't change object position through rigidbody, You can only change transform.position.
I think it could be better, if You set isKinematic to false and add stopping distance to enemies, so they can't get too close to player.

Being that your player can no longer be effected by the physics engine, you'd have to manipulate the object's transform manually. Your script isn't ideally setup for it currently, but if I was to hack it into it and try to make it work it would look something like this:
(you can change it from fixedUpdate to update if you're no longer utilizing the physics engine)
void update(){
float x = Input.GetAxisRaw("Horizontal")* Time.Deltatime;
float z = Input.GetAxisRaw("Vertical") * Time.Deltatime;
transform.position = new Vector3(transform.position.x+x,0,transform.position.z+z);

Another way of doing this is to lock the position of Y for the player (assuming Y is the positive "up" direction). isKinimatic is best when you want to move the player or objects around yourself.
I would say upping the mass is better in this case, and you can keep isKinematic unchecked in this case then too. Also apply the lock for Y movement (again if it is the "up" direction from the plane)
Let me know what your solution is regardless, I've had some issues in the past as well with these types of events happening

Unity: How to create a Knockback vector2 directions script (c#)

I have this topdown game on which I want to create a knockback effect when my player collides with my object. I want to create a knock back script using OnTriggerEnter2D. I want the knock back script to look like this. How Would I do that? (sorry I'm a bit of a noob)
(http://noobtuts.com/content/unity/2d-pong-game/vector2_directions.png)

Hei here is how I got it to work.
First here a basic move script:
public class Move : MonoBehaviour {
public Rigidbody2D rig;
public float speed = 0.2f;
public float maxSpeed = 5f;
void FixedUpdate ()
{
Vector2 vel = new Vector2 ( Input.GetAxis("Horizontal") /5f, Input.GetAxis("Vertical")/5f);
vel.Normalize ();
if (vel.sqrMagnitude > 0f && rig.velocity.sqrMagnitude < maxSpeed) {
rig.AddForce (vel * speed, ForceMode2D.Impulse);
} else {
rig.velocity = Vector2.zero;
}
}
}
And then the bouncing script:
public class CollideCtrl : MonoBehaviour
{
public float speed = 500f;
void OnCollisionEnter2D (Collision2D col) {
if(col.gameObject.CompareTag("Player")){
Debug.Log("Col");
Rigidbody2D rig = col.gameObject.GetComponent<Rigidbody2D>();
if(rig == null) { return;}
Vector2 velocity = rig.velocity;
rig.AddForce( -velocity * speed);
}
}
}
You now need to tweak those values. The effect works but is not perfect to my taste. I invite anyone to improve that answer with their suggestion or own answer coz this is a quick way but not a perfect one. That may give you some lead.
The player needs a Player tag, Rigidbody2D with no gravity and a 2D collision box. The box to collide with needs a BoxCollider2D and isTrigger as false. If you need it as trigger, then change the name and parameter of the collision method.

You could try using physics materials for this, documentation is here:
http://docs.unity3d.com/Manual/class-PhysicMaterial.html
It seems like just what you're looking for!