Optimizing Procedural terrain

CreateVisualMesh needs:

 yield return new WaitForSeconds(0.001f);

every so often. Maybe at line 64. This will let it generate some stuff, and then it'll yield to the render loop, and then it can come back and continue until it is done.

this is what i do for instantiating the chunks.

 for (float x = transform.position.x - viewSize; x < transform.position.x + viewSize; x+= Chunk.width)
         {
             for (float z = transform.position.z - viewSize; z < transform.position.z + viewSize; z+= Chunk.width)
             {
                 
                 Vector3 pos = new Vector3(x, 0, z);
                 pos.x = Mathf.Floor(pos.x / (float)Chunk.width) * Chunk.width;
                 pos.z = Mathf.Floor(pos.z / (float)Chunk.width) * Chunk.width;
                 
                 Chunk chunk = Chunk.FindChunk(pos);
                 if (chunk != null) continue;
                 
                  chunk = (Chunk)Instantiate(chunkFab, pos, Quaternion.identity);
                 
                 
                 
             }
         }

and this is what i use for creating a visual mesh

     public virtual IEnumerator CreateVisualMesh() {
         visualMesh = new Mesh();
         
         List<Vector3> verts = new List<Vector3>();
         List<Vector2> uvs = new List<Vector2>();
         List<int> tris = new List<int>();
         
         
         for (int x = 0; x < width; x++)
         {
             for (int y = 0; y < height; y++)
             {
                 for (int z = 0; z < width; z++)
                 {
                     if (map[x,y,z] == 0) continue;
                     
                     byte block = GetByte(x,y,z);
                     Vector3 start = new Vector3(x, y, z);
                     Vector3 offset1, offset2;
                     
                     if (IsTransparent(x, y - 1, z))
                     {
                         offset1 = Vector3.left;
                         offset2 = Vector3.back;
                         DrawFace(start + Vector3.right, offset1, offset2, block,verts,uvs,tris);
                     }
                     
                     if (IsTransparent(x, y + 1, z))
                     {
                         offset1 = Vector3.right;
                         offset2 = Vector3.back;
                         DrawFace(start + Vector3.up, offset1, offset2, block,verts,uvs,tris);
                     }
                     
                     if (IsTransparent(x - 1, y, z))
                     {
                         offset1 = Vector3.back;
                         offset2 = Vector3.down;
                         DrawFace(start + Vector3.up, offset1, offset2, block,verts,uvs,tris);
                     }
                     
                     if (IsTransparent(x + 1, y, z))
                     {
                         offset1 = Vector3.forward;
                         offset2 = Vector3.down;
                         DrawFace(start + Vector3.right + Vector3.up + Vector3.back, offset1, offset2, block,verts,uvs,tris);
                     }
                     
                     
                     if (IsTransparent(x, y, z - 1))
                     {
                         offset1 = Vector3.right;
                         offset2 = Vector3.down;
                         DrawFace(start + Vector3.back + Vector3.up, offset1, offset2, block,verts,uvs,tris);
                     }
                     
                     
                     if (IsTransparent(x, y, z + 1))
                     {
                         offset1 = Vector3.left;
                         offset2 = Vector3.down;
                         DrawFace(start + Vector3.up + Vector3.right, offset1, offset2, block,verts,uvs,tris);
                     }
                 }
             }
         }
                     
         visualMesh.vertices = verts.ToArray();
         visualMesh.uv = uvs.ToArray();
         visualMesh.triangles = tris.ToArray();
         visualMesh.RecalculateBounds();
         visualMesh.RecalculateNormals();
         
         meshFilter.mesh = visualMesh;
         meshCollider.sharedMesh = visualMesh;
         
         yield return 0;
         
     }
     
     public void DrawFace(Vector3 start, Vector3 offset1, Vector3 offset2, byte block,List<Vector3> verts, List<Vector2> uv, List<int> tris)
     {
         Terrain terrain = Terrain.activeTerrain;
         int index = verts.Count;
         
         BlockType blockType = Terrain.blocks.GetBlock(block);
         float zoom = 0.0625F;
         
         Vector2 uvBase = blockType.uv;
         
         if(blockType.sideTexture == true)
         {
             if ((offset2 == Vector3.down))
             {
                 uvBase = blockType.side;
             }
         }
         if(blockType.bottomTexture == true)
         {
             if (!(offset2 == Vector3.down) && !(offset1 == Vector3.right))
             {
                 uvBase = blockType.bottom;
             }
         }
         
         uv.Add(uvBase);
         uv.Add(uvBase + new Vector2(-zoom , 0F));
         uv.Add(uvBase + new Vector2(0F , zoom));
         uv.Add(uvBase + new Vector2(-zoom , zoom));
         
         verts.Add (start);
         verts.Add (start + offset1);
         verts.Add (start + offset2);
         verts.Add (start + offset1 + offset2);
         tris.Add (index + 0);
         tris.Add (index + 1);
         tris.Add (index + 2);
         tris.Add (index + 3);
         tris.Add (index + 2);
         tris.Add (index + 1);
         
     }