void MakeGrid()
{
var bounds = _voids
.GetComponentsInChildren <MeshCollider>()
.Select(c => c.bounds)
.ToArray();
var voxelSize = float.Parse(_voxelSize);
_grid = Grid3d.MakeGridWithBounds(bounds, voxelSize);
// shortest path to test if connectivity is working
var faces = _grid.GetFaces().Where(f => f.IsActive).ToList();
var graphEdges = faces.Select(f => new TaggedEdge <Voxel, Face>(f.Voxels[0], f.Voxels[1], f));
var graph = graphEdges.ToUndirectedGraph <Voxel, TaggedEdge <Voxel, Face> >();
var start = _grid.GetVoxels().ElementAt(2);
var end = _grid.GetVoxels().ElementAt(250);
var shortest = graph.ShortestPathsDijkstra(_ => 1, start);
shortest(end, out var path);
var current = start;
_flowPath = new List <Voxel>();
_flowPath.Add(current);
foreach (var face in path)
{
current = face.GetOtherVertex(current);
_flowPath.Add(current);
}
}