diff --git a/src/Collision/Fixed/SpatialHash2D.cs b/src/Collision/Fixed/SpatialHash2D.cs
index 0821799..9d1a87a 100644
--- a/src/Collision/Fixed/SpatialHash2D.cs
+++ b/src/Collision/Fixed/SpatialHash2D.cs
@@ -7,17 +7,20 @@ namespace MoonWorks.Collision.Fixed
 	/// Used to quickly check if two shapes are potentially overlapping.
 	/// </summary>
 	/// <typeparam name="T">The type that will be used to uniquely identify shape-transform pairs.</typeparam>
-	public class SpatialHash2D<T, U> where T : struct, System.IEquatable<T> where U : IHasAABB2D
+	public class SpatialHash2D<T, U> where T : struct, System.IEquatable<T>
 	{
 		private readonly Fix64 cellSize;
 
 		private readonly Dictionary<long, HashSet<T>> hashDictionary = new Dictionary<long, HashSet<T>>();
-		private readonly Dictionary<T, (U, Transform2D, uint)> IDLookup = new Dictionary<T, (U, Transform2D, uint)>();
+		private readonly Dictionary<T, AABB2D> IDBoxLookup = new Dictionary<T, AABB2D>();
+		private readonly Dictionary<T, U> IDDataLookup = new Dictionary<T, U>();
 
-		public int MinX { get; private set; } = 0;
-		public int MaxX { get; private set; } = 0;
-		public int MinY { get; private set; } = 0;
-		public int MaxY { get; private set; } = 0;
+		private readonly HashSet<T> DynamicIDs = new HashSet<T>();
+
+		private int MinX;
+		private int MaxX;
+		private int MinY;
+		private int MaxY;
 
 		private Queue<HashSet<T>> hashSetPool = new Queue<HashSet<T>>();
 
@@ -35,12 +38,11 @@ namespace MoonWorks.Collision.Fixed
 		/// Inserts an element into the SpatialHash.
 		/// </summary>
 		/// <param name="id">A unique ID for the shape-transform pair.</param>
-		/// <param name="shape"></param>
-		/// <param name="transform2D"></param>
-		/// <param name="collisionGroups">A bitmask value specifying the groups this object belongs to.</param>
-		public void Insert(T id, U shape, Transform2D transform2D, uint collisionGroups = uint.MaxValue)
+		public void Insert(T id, AABB2D aabb, Transform2D transform2D, U data, bool dynamic = true)
 		{
-			var box = AABB2D.Transformed(shape.AABB, transform2D);
+			Remove(id);
+
+			var box = AABB2D.Transformed(aabb, transform2D);
 			var minHash = Hash(box.Min);
 			var maxHash = Hash(box.Max);
 
@@ -52,19 +54,26 @@ namespace MoonWorks.Collision.Fixed
 				}
 
 				hashDictionary[key].Add(id);
-				IDLookup[id] = (shape, transform2D, collisionGroups);
+				IDDataLookup[id] = data;
 			}
 
 			MinX = System.Math.Min(MinX, minHash.Item1);
 			MinY = System.Math.Min(MinY, minHash.Item2);
 			MaxX = System.Math.Max(MaxX, maxHash.Item1);
 			MaxY = System.Math.Max(MaxY, maxHash.Item2);
+
+			if (dynamic)
+			{
+				DynamicIDs.Add(id);
+			}
+
+			IDBoxLookup[id] = box;
 		}
 
 		/// <summary>
 		/// Retrieves all the potential collisions of a shape-transform pair. Excludes any shape-transforms with the given ID.
 		/// </summary>
-		public RetrieveEnumerator Retrieve<V>(T id, V hasAABB, Transform2D transform2D, uint collisionMask = uint.MaxValue) where V : IHasAABB2D
+		public RetrieveEnumerator Retrieve<V>(T id, V hasAABB, Transform2D transform2D) where V : IHasAABB2D
 		{
 			var box = AABB2D.Transformed(hasAABB.AABB, transform2D);
 			var (minX, minY) = Hash(box.Min);
@@ -78,18 +87,17 @@ namespace MoonWorks.Collision.Fixed
 			return new RetrieveEnumerator(
 				this,
 				Keys(minX, minY, maxX, maxY),
-				id,
-				collisionMask
+				id
 			);
 		}
 
 		/// <summary>
 		/// Retrieves all the potential collisions of a shape-transform pair.
 		/// </summary>
-		public RetrieveEnumerator Retrieve<V>(V hasAABB, Transform2D transform2D, uint collisionMask = uint.MaxValue) where V : IHasAABB2D
+		public RetrieveEnumerator Retrieve<V>(V hasAABB, Transform2D transform2D) where V : IHasAABB2D
 		{
 			var box = AABB2D.Transformed(hasAABB.AABB, transform2D);
-			return Retrieve(box, collisionMask);
+			return Retrieve(box);
 		}
 
 		/// <summary>
@@ -97,7 +105,7 @@ namespace MoonWorks.Collision.Fixed
 		/// </summary>
 		/// <param name="aabb">A transformed AABB.</param>
 		/// <returns></returns>
-		public RetrieveEnumerator Retrieve(AABB2D aabb, uint collisionMask = uint.MaxValue)
+		public RetrieveEnumerator Retrieve(T id, AABB2D aabb)
 		{
 			var (minX, minY) = Hash(aabb.Min);
 			var (maxX, maxY) = Hash(aabb.Max);
@@ -110,14 +118,29 @@ namespace MoonWorks.Collision.Fixed
 			return new RetrieveEnumerator(
 				this,
 				Keys(minX, minY, maxX, maxY),
-				collisionMask
+				id
 			);
 		}
 
-		public void Update(T id, U shape, Transform2D transform2D, uint collisionGroups = uint.MaxValue)
+		/// <summary>
+		/// Retrieves objects based on a pre-transformed AABB.
+		/// </summary>
+		/// <param name="aabb">A transformed AABB.</param>
+		/// <returns></returns>
+		public RetrieveEnumerator Retrieve(AABB2D aabb)
 		{
-			Remove(id);
-			Insert(id, shape, transform2D, collisionGroups);
+			var (minX, minY) = Hash(aabb.Min);
+			var (maxX, maxY) = Hash(aabb.Max);
+
+			if (minX < MinX) { minX = MinX; }
+			if (maxX > MaxX) { maxX = MaxX; }
+			if (minY < MinY) { minY = MinY; }
+			if (maxY > MaxY) { maxY = MaxY; }
+
+			return new RetrieveEnumerator(
+				this,
+				Keys(minX, minY, maxX, maxY)
+			);
 		}
 
 		/// <summary>
@@ -125,24 +148,24 @@ namespace MoonWorks.Collision.Fixed
 		/// </summary>
 		public void Remove(T id)
 		{
-			if (IDLookup.TryGetValue(id, out var data))
+			if (IDBoxLookup.TryGetValue(id, out var aabb))
 			{
-				var (shape, transform, collisionGroups) = data;
-
-				var box = AABB2D.Transformed(shape.AABB, transform);
-				var minHash = Hash(box.Min);
-				var maxHash = Hash(box.Max);
+				var minHash = Hash(aabb.Min);
+				var maxHash = Hash(aabb.Max);
 
 				foreach (var key in Keys(minHash.Item1, minHash.Item2, maxHash.Item1, maxHash.Item2))
 				{
-					if (hashDictionary.ContainsKey(key))
+					if (hashDictionary.TryGetValue(key, out HashSet<T> value))
 					{
-						hashDictionary[key].Remove(id);
+						value.Remove(id);
 					}
 				}
 
-				IDLookup.Remove(id);
+				IDDataLookup.Remove(id);
+				IDBoxLookup.Remove(id);
 			}
+
+			DynamicIDs.Remove(id);
 		}
 
 		/// <summary>
@@ -155,7 +178,19 @@ namespace MoonWorks.Collision.Fixed
 				hash.Clear();
 			}
 
-			IDLookup.Clear();
+			IDDataLookup.Clear();
+			IDBoxLookup.Clear();
+		}
+
+		/// <summary>
+		/// Removes
+		/// </summary>
+		public void ClearDynamic()
+		{
+			foreach (var id in DynamicIDs)
+			{
+				Remove(id);
+			}
 		}
 
 		private static long MakeLong(int left, int right)
@@ -239,15 +274,13 @@ namespace MoonWorks.Collision.Fixed
 			private bool HashSetEnumeratorActive;
 			private HashSet<T> Duplicates;
 			private T? ID;
-			private uint CollisionMask;
 
 			public RetrieveEnumerator GetEnumerator() => this;
 
 			internal RetrieveEnumerator(
 				SpatialHash2D<T, U> spatialHash,
 				KeysEnumerator keysEnumerator,
-				T id,
-				uint collisionMask
+				T id
 			) {
 				SpatialHash = spatialHash;
 				KeysEnumerator = keysEnumerator;
@@ -255,13 +288,11 @@ namespace MoonWorks.Collision.Fixed
 				HashSetEnumeratorActive = false;
 				Duplicates = SpatialHash.AcquireHashSet();
 				ID = id;
-				CollisionMask = collisionMask;
 			}
 
 			internal RetrieveEnumerator(
 				SpatialHash2D<T, U> spatialHash,
-				KeysEnumerator keysEnumerator,
-				uint collisionMask
+				KeysEnumerator keysEnumerator
 			) {
 				SpatialHash = spatialHash;
 				KeysEnumerator = keysEnumerator;
@@ -269,7 +300,6 @@ namespace MoonWorks.Collision.Fixed
 				HashSetEnumeratorActive = false;
 				Duplicates = SpatialHash.AcquireHashSet();
 				ID = null;
-				CollisionMask = collisionMask;
 			}
 
 			public bool MoveNext()
@@ -293,7 +323,6 @@ namespace MoonWorks.Collision.Fixed
 
 				// conditions
 				var t = HashSetEnumerator.Current;
-				var collisionGroups = SpatialHash.IDLookup[t].Item3;
 
 				if (Duplicates.Contains(t))
 				{
@@ -302,7 +331,7 @@ namespace MoonWorks.Collision.Fixed
 
 				if (ID.HasValue)
 				{
-					if (ID.Value.Equals(t) || (CollisionMask & collisionGroups) == 0)
+					if (ID.Value.Equals(t))
 					{
 						return MoveNext();
 					}
@@ -312,13 +341,13 @@ namespace MoonWorks.Collision.Fixed
 				return true;
 			}
 
-			public (T, U, Transform2D, uint) Current
+			public (T, U) Current
 			{
 				get
 				{
 					var t = HashSetEnumerator.Current;
-					var (u, transform, groups) = SpatialHash.IDLookup[t];
-					return (t, u, transform, groups);
+					var u = SpatialHash.IDDataLookup[t];
+					return (t, u);
 				}
 			}
 		}