Question by joeyzhao2018 · Nov 24, 2021 at 01:58 PM · physics2d boxcollider2d

Is Physics2D BoxCast accuracy influenced by tranform.scale ?

Replication steps

Create two empty game objects with any sprite.
Scale should be (1,1,1) by default.
Add a BoxCollider2D to each of the game object.
Add following Mover.cs script to them and assign their own BoxCollider2D to the property.
Drag one game object to the left and one to the right. y axis values are the same. Assign 1 as the X_dir property to the object on the left and -1 to the object on the right, i.e. let them run toward each other.
In Edit / Project Settings / Physics 2, turn off Queries Start In Colliders

Script

 public class Mover: MonoBehaviour 
 { 
     public BoxCollider2D boxCollider;
     public float x_dir;
     protected virtual void Start(){
         boxCollider = GetComponent<BoxCollider2D>();
     }    
     protected void FixedUpdate()
     {
         UpdateMotor(new Vector3(x_dir, 0,0));
     }
 
     protected virtual void UpdateMotor(Vector3 input)
     {
         Vector3 delta = new Vector3(input.x * Time.deltaTime, input.y * Time.deltaTime, 0);
        
         RaycastHit2D hit = Physics2D.BoxCast(transform.position, boxCollider.size, 0, new Vector2(0, delta.y), Mathf.Abs(delta.y));     
         if (hit.collider == null) {
             // Make this thing move
             transform.Translate(0, delta.y, 0);
         } 
         hit = Physics2D.BoxCast(transform.position, boxCollider.size, 0, new Vector2(delta.x, 0), Mathf.Abs(delta.x));
         if (hit.collider == null) {
             // Make this thing move
             transform.Translate(delta.x, 0, 0);
         } 
     }
 }