Mesh collider isn't working

Good Evening!

I stumbled upon a problem when I was experimenting with mesh colliders.

I am currently making a 2D game where I generate the ground by making a mesh of predefined points with the help of a triangulation method. I attached a mesh collider to it and I set the MeshCollider.sharedMesh in the start method after the triangulation process ended. But my player with raycasting ground detection falls through it.
I continued experimenting and I found out that my player falls through everything with mesh collider.

Here is my collision detection script of the player:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [RequireComponent(typeof(BoxCollider2D))]
5. public class Controller2D : MonoBehaviour
6. {
7.    
8.     public LayerMask collisionMask;
9.  
10.     const float skinWidth = .015f;
11.     public int horizontalRayCount = 4;
12.     public int verticalRayCount = 4;
13.  
14.     float horizontalRaySpacing;
15.     float verticalRaySpacing;
16.  
17.     BoxCollider2D collider;
18.     RaycastOrigins raycastOrigins;
19.     public CollisionInfo collisions;
20.  
21.     void Start()
22.     {
23.         collider = GetComponent<BoxCollider2D>();
24.         CalculateRaySpacing();
25.     }
26.  
27.    
28.     public void Move(Vector3 velocity)
29.     {
30.         UpdateRaycastOrigins();
31.         collisions.Reset();
32.  
33.         if (velocity.x != 0)
34.         {
35.             HorizontalCollisions(ref velocity);
36.         }
37.         if (velocity.y != 0)
38.         {
39.             VerticalCollisions(ref velocity);
40.         }
41.  
42.         transform.Translate(velocity);
43.     }
44.  
45.     void HorizontalCollisions(ref Vector3 velocity)
46.     {
47.         float directionX = Mathf.Sign(velocity.x);
48.         float rayLength = Mathf.Abs(velocity.x) + skinWidth;
49.  
50.         for (int i = 0; i < horizontalRayCount; i++)
51.         {
52.             Vector2 rayOrigin = (directionX == -1) ? raycastOrigins.bottomLeft : raycastOrigins.bottomRight;
53.             rayOrigin += Vector2.up * (horizontalRaySpacing * i);
54.             RaycastHit2D hit = Physics2D.Raycast(rayOrigin, Vector2.right * directionX, rayLength, collisionMask);
55.  
56.             Debug.DrawRay(rayOrigin, Vector2.right * directionX * rayLength, Color.red);
57.  
58.             if (hit)
59.             {
60.                 velocity.x = (hit.distance - skinWidth) * directionX;
61.                 rayLength = hit.distance;
62.  
63.                 collisions.left = (directionX == -1);
64.                 collisions.right = (directionX == 1);
65.             }
66.            
67.         }
68.     }
69.  
70.     void VerticalCollisions(ref Vector3 velocity)
71.     {
72.         float directionY = Mathf.Sign(velocity.y);
73.         float rayLength = Mathf.Abs(velocity.y) + skinWidth;
74.  
75.         for (int i = 0; i < verticalRayCount; i++)
76.         {
77.             Vector2 rayOrigin = (directionY == -1) ? raycastOrigins.bottomLeft : raycastOrigins.topLeft;
78.             rayOrigin += Vector2.right * (verticalRaySpacing * i + velocity.x);
79.             RaycastHit2D hit = Physics2D.Raycast(rayOrigin, Vector2.up * directionY, rayLength, collisionMask);
80.  
81.             Debug.DrawRay(rayOrigin, Vector2.up * directionY * rayLength, Color.red);
82.  
83.             if (hit)
84.             {
85.                 velocity.y = (hit.distance - skinWidth) * directionY;
86.                 rayLength = hit.distance;
87.  
88.                 collisions.above = (directionY == 1);
89.                 collisions.below = (directionY == -1);
90.             }
91.         }
92.     }
93.  
94.     void UpdateRaycastOrigins()
95.     {
96.         Bounds bounds = collider.bounds;
97.         bounds.Expand(skinWidth * -2);
98.  
99.         raycastOrigins.bottomLeft = new Vector2(bounds.min.x, bounds.min.y);
100.         raycastOrigins.bottomRight = new Vector2(bounds.max.x, bounds.min.y);
101.         raycastOrigins.topLeft = new Vector2(bounds.min.x, bounds.max.y);
102.         raycastOrigins.topRight = new Vector2(bounds.max.x, bounds.max.y);
103.     }
104.  
105.     void CalculateRaySpacing()
106.     {
107.         Bounds bounds = collider.bounds;
108.         bounds.Expand(skinWidth * -2);
109.  
110.         horizontalRayCount = Mathf.Clamp(horizontalRayCount, 2, int.MaxValue);
111.         verticalRayCount = Mathf.Clamp(verticalRayCount, 2, int.MaxValue);
112.  
113.         horizontalRaySpacing = bounds.size.y / (horizontalRayCount - 1);
114.         verticalRaySpacing = bounds.size.x / (verticalRayCount - 1);
115.     }
116.  
117.     struct RaycastOrigins
118.     {
119.         public Vector2 topLeft, topRight;
120.         public Vector2 bottomLeft, bottomRight;
121.     }
122.  
123.     public struct CollisionInfo
124.     {
125.         public bool above, below;
126.         public bool left, right;
127.  
128.         public void Reset()
129.         {
130.             above = below = false;
131.             left = right = false;
132.         }
133.     }
134. }

 

how do you set your LayerMask (i.e. collisionMask in your code)?

 

Thank you for your answer.

I set it in manually in the inspector, but I checked it twice and it's aligned with the mesh's object.

 

what I meant is are you absolutely sure you're setting the appropriate value?
I can't tell if you're experienced with bitmasks in general, but that's the most common source of this type of error.

 

I did some testing and it seems like raycast just doesn't work with any mesh filter object in my project. Here is a video: https://easyupload.io/uhtacb

As you can see the rays collide with every other object except the quad with mesh filter. Also, I haven't use layermask for this experiment.

 

In Unity, 2D and 3D physics are separate systems, so something like a mesh collider (which is 3D) is not going to work with Raycast2D. You either need to use the regular 3D Raycast or change your mesh collider to a polygon collider 2d instead.

https://docs.unity3d.com/Manual/class-PolygonCollider2D.html

2D physics objects and functions should all have the character "2D" in the name.

 

Thank you for your answer!

I have solved the problem with polygon colliders.