Trouble with using Physics2D.BoxCast in order to make a game object collide with another game object

So I'm trying to figure out how to simulate gravity on a game object that has a Kinematic Rigidbody2D by using the Physics2D.BoxCast function but I'm finding it difficult to get the object to collide flush with the ground underneath it as it is falling. It seems to fall through the ground before it stops.

Here is the code that I've written:

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5.  
6. public class Simple2 : MonoBehaviour
7. {
8.  
9.     public bool grounded;
10.     public LayerMask _whatIsGround;
11.     public Vector2 velocity;
12.     private Rigidbody2D _rb;
13.  
14.     // Start is called before the first frame update
15.     void Start()
16.     {
17.         _rb = GetComponent<Rigidbody2D>();
18.     }
19.  
20.     // Update is called once per frame
21.     void FixedUpdate()
22.     {
23.         RaycastHit2D boxResult;
24.         boxResult = Physics2D.BoxCast(transform.position, new Vector2(1,0.5f),0f, new Vector2(0,-1),0.25f,_whatIsGround);
25.  
26.         if(boxResult.collider != null){
27.  
28.            grounded = true;
29.        
30.         }else{
31.  
32.            grounded = false;
33.        
34.         }
35.  
36.  
37.         if(grounded == true){
38.  
39.             velocity.y = 0;
40.  
41.         }else if(grounded == false){
42.  
43.            velocity += Physics2D.gravity * Time.deltaTime;
44.          
45.  
46.  
47.         }
48.          _rb.MovePosition(new Vector2(_rb.position.x,_rb.position.y + velocity.y * Time.deltaTime * 3));
49.      
50.     }
51. }
52.  
53.  

Here is a video of the issue:

Could someone recommend a way to solve this problem that I'm having? If you think there's a better way of going about this without using Physics2D.BoxCast please let me know.

Kind regards

 

Around line 39 above, use the

.point

field of the returned

RaycastHit2D

to place your object at the correct altitude. Obviously if the lower edge of your character is not at its numeric center, you will need to vertically offset it appropriately.

 

Yeah I've been at this for months and I am really frustrated by my lack of progress. I'm basically trying to figure out how to implement common 2D platformer physics and collisions using a Kinematic Rigidbody2D for the Player rather than relying on the "out of the box" Physics that Unity provides through using a Dynamic Rigidbody2D. So at the moment I'm focusing on the following:

1. Making the Player stop flush against the ground beneath him once as he is falling(ground collision).
2. Wall collisions

Initially I thought to do this with using raycasts that fire from the bottom of the Player towards the ground and then once the distance of the raycast equals zero I make the value of gravity zero so that the Player will rest flush against the ground. However I had problems with this as I had to account for floating point imprecision(hit.distance will rarely be zero) and the way I got it to work in the end with code seemed very ungraceful and buggy.

So recently I came across Rigidbody2D.Cast and Physics2D.BoxCast and I was hoping that using these things could provide a graceful and non-buggy way of creating the collisions that I want.

You've suggested that I use either Collider2D.Cast or Rigidbody2D.Cast and I've been reading about Collider2D.Cast on Unity docs but I don't really understand how to actually implement it from reading what's on that page? Underneath the declaration heading it has the following:

Code (CSharp):

1. public int Cast(Vector2 direction, RaycastHit2D[] results, float distance = Mathf.Infinity, bool ignoreSiblingColliders = true);

I don't understand what am I supposed to do with this information? It seems that I'm supposed to declare an int variable called Cast but I don't understand what I'm supposed to do with the parameters? Unity Docs seems to present information in quite an unpalatable way for a beginner such as myself.