Develop Reference

Sphere Collider, not pushing things when size is changed

So I'm trying to make a little pushback effect in my tests arena, I've got a sphere collider and here is my script:
// PushBack Class Script
if (Input.GetKeyDown(KeyCode.Q))
{
explosion_ball.transform.position = transform.position;
StartCoroutine(WaitAndPrint());
}
IEnumerator WaitAndPrint()
{
float i = 0;
while (i < 1)
{
i += 0.01f;
explosion_ball.radius = curve.Evaluate(i) * 10;
yield return new WaitForSeconds(0.01f);
}
}
//__________//
Sphere collider is set and stuff, but it doesn't push things back like I thought it would.
Thanks!
Edit:
explosion_ball is a sphere collider, I'm changing it with the point on the animation curve and * it by 10

EDIT:Unity Rigid bodies go to sleep so[Also Change interpolation to continuous if collider changes size too quickly]
A.check if obstacle rigid bodies are Sleeping with onTriggerEnter and Wake Up
void OnTriggerEnter(collider){ if(rb.IsSleeping()){rb.WakeUp();}
or
B.Attach this forceWakeUp Script to all Objects you want to be obstacles.
using UnityEngine;
public class forceWakeUp : MonoBehaviour
{
private Rigidbody rb;
void Start()
{
rb = gameObject.GetComponent<Rigidbody>();
}
void Update()
{
if(rb.IsSleeping()){rb.WakeUp();}
}
}
Forcibly Keeping Many objects awake Will impact performance.So ,your decision.
You need to scale up the collider on the object by radius and all the objects it is supposed to wobble need to have Rigid body component attached to them
2.if you ARE doing above things and its not adding any force you could just add a force on all the overlapping objects using the "OnCollisionEnterTrigger" and AddForceMethod radially away from the Sphere
Obstacle.position - Sphere.position is the vector Radially away from Sphere I think.
You don't need coroutines for this I think.

While searching through the Unity scripting API, found a method in there called
Rigidbody.AddExplosionForce(explosionForce, explosionPosition, explosionRadius, upwardsModifier, mode)
In order to get the rigid bodies that are to be affected by the explosion I would need to get them using Physics.OverlapSphere(position, radius) this gets all of the objects within the radius variable, then get the component.
Combining these two would also look like:
Collider[] colliders = Physics.OverlapSphere(transform.position, radius);
foreach (Collider hit in colliders)
{
if (hit.transform.tag == "Interactable")
{
if (hit.gameObject != hitgameObject)
{
Rigidbody rb = hit.GetComponent<Rigidbody>();
if (rb != null)
rb.AddExplosionForce(power, transform.position, radius, upForce, ForceMode.Impulse);
}
}
}
If there is any explaining that you would like me to do about my variables mentioned I will reply :)
Thanks for the help guys.

I don't know your curve and what values that evaluation produces, but you can check your code visually with Window/Analysis/Physics Debugger, or write a gizmo:
private void OnDrawGizmos()
{
Gizmos.color = new(1.0f, 0.0f, 0.0f, 0.5f);
Gizmos.DrawSphere(explosion_ball.transform.position, explosion_ball.radius);
}
Or simply just use https://docs.unity3d.com/ScriptReference/Rigidbody.AddExplosionForce.html

How to spawn objects in Unity?

I am trying to build a flappy bird like game and I am trying to spawn enemy birds and gold coins so I have written the C# code and the made the prefabs, but when I run the bird and the coins are not respawning.
This is the respawn code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SpawnPlayer : MonoBehaviour
{
public GameObject GameObjectToSpawn;
private GameObject Clone;
public float timeToSpawn = 4f;
public float FirstSpawn = 10f;
// Update is called once per frame
void Update()
{
FirstSpawn -= Time.deltaTime;
if (FirstSpawn <= 0f)
{
Clone = Instantiate(GameObjectToSpawn, gameObject.transform.localPosition, Quaternion.identity) as GameObject;
FirstSpawn = timeToSpawn;
}
}
}
screenshot of unity:
This where i am respawning the first enemy bird:

From your second screenshot it seems to be spawned but way off the screen! You can still see the tiny little island in the bottom left corner.
You thought seems to be that you have to spawn it in the Canvas pixel space using the spawn point's localPosition. But this is not the case since Instantiate places it into the scene root (without any parent) with absolute world-space position into the scene.
You should rather actually place the spawn point to the absolute world position where the spawn should happen and rather use
Clone = Instantiate(GameObjectToSpawn, transform.position, Quaternion.identity);
Btw no need for the as GameObject since Instantiate already returns the type of the given prefab.

How to move a RigidBody2D to a position while still checking for collision

I am currently creating a game in Unity, in which you move a ball around using OnMouseDrag(), a CircleCollider2D and a RigidBody2D. This is how I set the position of the ball:
private void OnMouseDrag()
{
Vector2 mouseInWorld = Camera.main.ScreenToWorldPoint(Input.mousePosition);
playerRb.position = new Vector3(mouseInWorld.x, mouseInWorld.y, 0);
}
I still want the ball to slide on collision while the mouse moves around. Is there a way to do this?
I have tried RigidBody2D.MovePosition(), but the ball jumped around from one point to another, and Raycasts but couldn't get that to work either.
EDIT:
This is what I've got now:
playerRb.velocity = new Vector3(mouseInWorld.x - playerRb.position.x, mouseInWorld.y - playerRb.position.y, 0);
Now the problem is, that the ball lags behind the mousePosition.

When you use RigidBody.MovePosition, you don't call the physics engine and so it ignores collisions. If you want collisions to happen you need to use RigidBody.Velocity instead.
Doing this change will require you to make some change to your code though because what you give to RigidBody.Velocity is a velocity and not a position so you will need to calculate the velocity required in x,y (and z if you are in 3d) to reach your destination.
I invite you to read the Unity page about velocity for more info
https://docs.unity3d.com/ScriptReference/Rigidbody-velocity.html

Note: This will make the player/ball stick to collisions.
Modifying the velocity could cause the ball to bounce around unexpectedly when the ball collides with the wall. I would use a CircleCast for this, check if it hit anything, then use MovePosition accordingly:
float cursorDepth;
Rigidbody2D playerRb;
CircleCollider cc;
void Awake()
{
playerRb = GetComponent<Rigidbody2D>();
cc = GetComponent<CircleCollider>();
}
private void OnMouseDrag()
{
Vector2 mouseInWorld = Camera.main.ScreenToWorldPoint(Input.mousePosition);
Vector2 posToMouse = mouseInWorld - playerRb.position;
RaycastHit2D hit = Physics2D.CircleCast(playerRb.position,
cc.radius * transform.lossyScale.x, posToMouse, posToMouse.magnitude);
if (hit.collider != null)
{
mouseInWorld = hit.centroid;
}
playerRb.MovePosition(mouseInWorld);
}
But notice that if the ball can't move all the way to the mouse, it might cause the drag to end. So, plan accordingly.

making a 2D GameObject react to the position of another 2D GameObject

So, my boss moves in a specific direction when it detects the player. The problem I'm having is how to get the boss to move depending on where the player is within a certain proximity. So if the boss is on the player's left, he'll move to the left. If he's on the player's right, he'll move to the right. But I can't figure out how to make him react based on distance. Right now I'm just doing a Debug.Log to save a few seconds.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class phantom : MonoBehaviour {
private Rigidbody2D rb;
private Animator anim;
public Transform Target;
void Start ()
{
rb = GetComponent<Rigidbody2D> ();
anim = GetComponent<Animator> ();
}
void Update ()
{
if (transform.position.x > Target.position.x ) {
Debug.Log ("left");
}
if (transform.position.x < Target.position.x ) {
Debug.Log ("right");
}
}
}

You could use the Vector3.Distance method to determine the distance between your two object based on thier respective transform. That way, you can modify your boss's behavior according to his proximity to the player. The smaller the magnitude value is, the closer your two transforms are.
Ex:
int distanceYouWant;
if(Vector3.Distance(transform.position, Target.position).magnitude < distanceToDoStuff)
{
Debug.Log("Boss do stuff!");
}
Here is the link to the Unity scripting API doc: https://docs.unity3d.com/ScriptReference/Vector3.Distance.html
Hope this helps!

I figured it out. I just made the function not in Update but with an OnTriggerEnterStay2d (Collider2D other). Then I placed a trigger collider on the same GameObject and only when it detects the Target (the player) does the debug come up.

Physics.IgnoreCollision Doing Nothing

I'm trying to make a BTD game. Since different balloons (enemies) have different speeds, they collide with each other when traveling on the path. I'm currently using this code:
void OnCollisionEnter (Collision coll)
{
if (coll.gameObject.tag == "Enemy")
{
Physics.IgnoreCollision(coll.collider, gameObject.GetComponent<SphereCollider>());
}
}
However, it doesn't appear to be working at all. The enemies still collide with each other. On the otherhand, the collision with the enemies and bullets from towers is working.
void OnTriggerEnter (Collider col)
{
if (col.tag == "Bullet")
{
CurrentHP -= col.GetComponent<TackShooterBullet>().Damage;
}
I've tried layer-collision (enemies to same layer & unchecking of the same layer collision in the layer collision matrix, but that doesn't work either. The enemy contains a sphere mesh filter, sphere collider, mesh renderer, rigidbody, material, and 2 scripts. Is there a better way to avoid collisions between the enemies. I'm asking this question since I've seen duplicates, but their solutions aren't working at all. I can provide more of my code if needed.
Edit for Clarity: Again, what I'm trying to accomplish is have the enemies be able to go through each other.
Edit (Fixed Problem): I found out to avoid Enemy Collisions, I could also remove rigidbody. However, removing the ridigbody would mess up the bullet --> enemy trigger in the enemy class. Therefore, I just wrote the collision between bullet & enemy in the bullet class instead.
using UnityEngine;
public class TackShooterBullet : MonoBehaviour {
private GameObject target;
public float Damage;
// Use this for initialization
void Start () {
target = transform.parent.GetComponent<TackShooterRange>().Target; // Target = Enemy[0] (First Enemy To Enter Range - Enemy is Removed from JList when exiting Range)
}
// Update is called once per frame
void Update()
{
Damage = gameObject.transform.parent.transform.parent.GetComponent<TackShooterLimitingRange1>().level * 20; // Upgrade Level * 20 = Damage Done
if (target == null) // If Enemy Exits Range
{
Destroy(gameObject); // Destroy Bullet
}
if (target != null) // Enemy Exists In Range
{
transform.position = Vector3.MoveTowards(transform.position, target.transform.position, 20 * Time.deltaTime); // Bullet Follows Enemy
Destroy(gameObject); // Destroy Bullet Upon Contact With Enemy
target.GetComponent<HealthOfEnemy>().CurrentHP -= Damage; // Enemy Loses Health
}
}
This allowed me to remove the OnTriggerEnter & OnCollisionEnter methods as well as the RigidBody from the Enemy Class as stated before, so these properties no longer affect the collisions between Enemies.

Unity has a built in function for easier collision detection called layer-based collision detection:
https://docs.unity3d.com/Manual/LayerBasedCollision.html
The documentation is really good. Just comment if you need further clarification.