static void CreateNonWalkableVolumes(NavNonWalkableCollection collection)
        {
            if (collection.m_Volumes == null)
            {
                collection.m_Volumes = new List <NavMeshModifierVolume>();
            }

            ClearVolumes(collection);

            var surfaces  = NavEdUtil.GetAllInActiveScene <NavMeshSurface>();
            var colliders = surfaces
                            .SelectMany(s => (s as NavMeshSurface).GetComponentsInChildren <Collider>());
            var threshold_sqr = 1.5f * 1.5f;

            foreach (Collider c in colliders)
            {
                if (c.GetComponentInChildren <NavMeshModifierVolume>() != null)
                {
                    // Skip so we can move them out of m_Volumes to make them persistent.
                    Debug.Log($"[NavMesh] Skipping NonWalkable generation on {c.name} because it already has a NavMeshModifierVolume child.", c);
                    continue;
                }
                // Get unrotated bounds. Hopefully these are tighter.
                var t   = c.transform;
                var rot = t.rotation;
                var pos = t.position;
                t.position = Vector3.zero;
                t.rotation = Quaternion.identity;
                Physics.SyncTransforms();
                var b = c.bounds;
                t.rotation = rot;
                t.position = pos;

                if (b.size.sqrMagnitude > threshold_sqr)
                {
                    var obj = new GameObject("Block NavMesh - " + t.name);
                    obj.transform.SetParent(t);
                    obj.transform.SetPositionAndRotation(pos, rot);
                    obj.transform.localPosition = Vector3.zero;
                    obj.transform.localRotation = Quaternion.identity;

                    var vol = obj.AddComponent <NavMeshModifierVolume>();
                    vol.area = (int)NavMeshAreaIndex.NotWalkable;

                    var offset = 0.2f;
                    var size   = b.size;
                    size      -= Vector3.one * offset;
                    vol.size   = size;
                    vol.center = b.center + Vector3.down * offset;
                    Undo.RegisterCreatedObjectUndo(obj, "Create No Walk Volumes");
                    collection.m_Volumes.Add(vol);
                }
            }
            Undo.RecordObject(collection, "Create No Walk Volumes");
        }
 static void ClearVolumes(NavNonWalkableCollection collection)
 {
     foreach (var entry in collection.m_Volumes)
     {
         if (entry != null)
         {
             GameObject.DestroyImmediate(entry.gameObject);
         }
     }
     collection.m_Volumes.Clear();
 }