Procedural Generated mesh collider creates invisible walls after the first iteration

Question

I have the a procedural generated cave code from the unity tutorials. It works great the first time but as soon as I press 'r' (the update key) to generate a new cave the mesh collider creates invisible walls. The only thing I can come up with is that the old mesh collider is not being erased, but I dont know how to do that. Attached bellow is the relevant portion of the code I am using.

 public class MarchingSquares : MonoBehaviour {
 
     public SquareGrid squareGrid;
     List<Vector3> vertices;
     List<int> triangles;
     public MeshFilter walls;
     //public bool is2D; 
     public static float wallHeight = 5;
 
     Dictionary<int,List<Triangle>> triangleDictionary = new Dictionary<int, List<Triangle>>();
     List<List<int>> outlines = new List<List<int>> ();
     HashSet<int> checkedVertices = new HashSet<int>();
 
     public void GenerateMesh(int[,] map, float squareSize){
 
         outlines.Clear ();
         checkedVertices.Clear ();
         triangleDictionary.Clear ();
 
         squareGrid=new SquareGrid(map,squareSize);
 
         vertices = new List<Vector3> ();
         triangles = new List<int> ();
         for (int x =0; x< squareGrid.squares.GetLength(0); x++) {
             for (int y=0; y< squareGrid.squares.GetLength(1); y++) {
                 TrigangluateSqaure(squareGrid.squares[x,y]);
             }
         }
 
         Mesh mesh = new Mesh ();
         GetComponent<MeshFilter>().mesh = mesh;
 
         mesh.vertices = vertices.ToArray ();
         mesh.triangles = triangles.ToArray ();
         mesh.RecalculateNormals();
         CreateWallMesh ();
     }
 
     void CreateWallMesh(){
 
         CalculateMeshOutlines ();
         List<Vector3> wallVertices = new List<Vector3> ();
         List<int> wallTriangles = new List<int> ();
         Mesh wallMesh = new Mesh ();
 
         foreach (List<int> outline in outlines) {
             for (int i=0; i<outline.Count-1;i++){
                 int startIndex = wallVertices.Count;
                 wallVertices.Add(vertices[outline[i]]);//top left
                 wallVertices.Add(vertices[outline[i+1]]);//bottom left
                 wallVertices.Add(vertices[outline[i]]-Vector3.up*wallHeight);//bottom left
                 wallVertices.Add(vertices[outline[i+1]]-Vector3.up*wallHeight);//bottom right
 
                 wallTriangles.Add (startIndex);
                 wallTriangles.Add (startIndex+2);
                 wallTriangles.Add (startIndex+3);
 
                 wallTriangles.Add (startIndex+3);
                 wallTriangles.Add (startIndex+1);
                 wallTriangles.Add (startIndex);
             }
         }
 
         wallMesh.vertices = wallVertices.ToArray ();
         wallMesh.triangles = wallTriangles.ToArray ();
         wallMesh.RecalculateBounds();
         walls.mesh = wallMesh;
 
         MeshCollider wallCollider = walls.gameObject.AddComponent<MeshCollider> ();
         wallCollider.sharedMesh.RecalculateBounds ();
         wallCollider.sharedMesh.RecalculateNormals ();
         //wallCollider.sharedMesh = wallMesh;
     }

Any help would be greatly appreciated

Answer 1

This is late, however I am sure others still have this issue and I have been able to fix it by removing this line and just getting the component:

 MeshCollider wallCollider = walls.gameObject.AddComponent<MeshCollider> ();

Here is my CreateWallMesh() method:

 void CreateWallMesh()
     {
 
         CalculateMeshOutlines();
 
         List<Vector3> wallVertices = new List<Vector3>();
         List<int> wallTriangles = new List<int>();
         Mesh wallMesh = new Mesh();
         float wallHeight = 5;
         MeshCollider wallCollider = walls.GetComponent<MeshCollider>();
 
         foreach (List<int> outline in outlines)
         {
             for (int i = 0; i < outline.Count - 1; i++)
             {
                 int startIndex = wallVertices.Count;
                 wallVertices.Add(vertices[outline[i]]); // left
                 wallVertices.Add(vertices[outline[i + 1]]); // right
                 wallVertices.Add(vertices[outline[i]] - Vector3.up * wallHeight); // bottom left
                 wallVertices.Add(vertices[outline[i + 1]] - Vector3.up * wallHeight); // bottom right
 
                 wallTriangles.Add(startIndex + 0);
                 wallTriangles.Add(startIndex + 2);
                 wallTriangles.Add(startIndex + 3);
 
                 wallTriangles.Add(startIndex + 3);
                 wallTriangles.Add(startIndex + 1);
                 wallTriangles.Add(startIndex + 0);
             }
         }
         wallMesh.vertices = wallVertices.ToArray();
         wallMesh.triangles = wallTriangles.ToArray();
         walls.mesh = wallMesh;
         wallCollider.sharedMesh = wallMesh;
     }

You just have to make sure that the Walls object has a Mesh Collider before the game launches, rather than having the code generate it.

Procedural Generated mesh collider creates invisible walls after the first iteration

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