diff --git a/Assets/IsoTools/Scripts/Internal/IsoUtils.cs b/Assets/IsoTools/Scripts/Internal/IsoUtils.cs
index 03ed446..59beb46 100644
--- a/Assets/IsoTools/Scripts/Internal/IsoUtils.cs
+++ b/Assets/IsoTools/Scripts/Internal/IsoUtils.cs
@@ -24,6 +24,40 @@ namespace IsoTools.Internal {
 		public static Vector3 vec3OneYZ { get { return new Vector3(0.0f, 1.0f, 1.0f); } }
 		public static Vector3 vec3OneXZ { get { return new Vector3(1.0f, 0.0f, 1.0f); } }
 
+		// ---------------------------------------------------------------------
+		//
+		// MinMax
+		//
+		// ---------------------------------------------------------------------
+
+		public struct MinMax {
+			public float min;
+			public float max;
+
+			public MinMax(float min, float max) {
+				this.min = min;
+				this.max = max;
+			}
+				
+			public float size {
+				get { return max - min; }
+			}
+
+			public float center {
+				get { return min / 2.0f + max / 2.0f; }
+			}
+
+			public bool Approximately(MinMax minmax) {
+				return
+					Mathf.Approximately(min, minmax.min) &&
+					Mathf.Approximately(max, minmax.max);
+			}
+
+			static public MinMax zero {
+				get { return new MinMax(); }
+			}
+		}
+
 		// ---------------------------------------------------------------------
 		//
 		// Abs/Min/Max
@@ -477,7 +511,7 @@ namespace IsoTools.Internal {
 		
 		public static IsoContactPoint[] IsoConvertContactPoints(ContactPoint[] points) {
 			var iso_points = new IsoContactPoint[points.Length];
-			for ( var i = 0; i < points.Length; ++i ) {
+			for ( int i = 0, e = points.Length; i < e; ++i ) {
 				iso_points[i] = new IsoContactPoint(points[i]);
 			}
 			return iso_points;
@@ -485,7 +519,7 @@ namespace IsoTools.Internal {
 
 		public static IsoRaycastHit[] IsoConvertRaycastHits(RaycastHit[] hits) {
 			var iso_hits = new IsoRaycastHit[hits.Length];
-			for ( var i = 0; i < hits.Length; ++i ) {
+			for ( int i = 0, e = hits.Length; i < e; ++i ) {
 				iso_hits[i] = new IsoRaycastHit(hits[i]);
 			}
 			return iso_hits;
diff --git a/Assets/IsoTools/Scripts/IsoObject.cs b/Assets/IsoTools/Scripts/IsoObject.cs
index 55f171b..ab1eb14 100644
--- a/Assets/IsoTools/Scripts/IsoObject.cs
+++ b/Assets/IsoTools/Scripts/IsoObject.cs
@@ -168,8 +168,8 @@ namespace IsoTools {
 			public bool               Dirty        = false;
 			public bool               Visited      = false;
 			public Rect               ScreenRect   = new Rect();
-			public Bounds             Bounds3d     = new Bounds();
 			public float              Offset3d     = 0.0f;
+			public IsoUtils.MinMax    MinMax3d     = IsoUtils.MinMax.zero;
 			public Vector2            MinSector    = Vector2.zero;
 			public Vector2            MaxSector    = Vector2.zero;
 			public HashSet<IsoObject> SelfDepends  = new HashSet<IsoObject>();
diff --git a/Assets/IsoTools/Scripts/IsoWorld.cs b/Assets/IsoTools/Scripts/IsoWorld.cs
index dfcf9f8..2e66956 100644
--- a/Assets/IsoTools/Scripts/IsoWorld.cs
+++ b/Assets/IsoTools/Scripts/IsoWorld.cs
@@ -343,34 +343,49 @@ namespace IsoTools {
 
 		bool UpdateIsoObjectBounds3d(IsoObject iso_object) {
 			if ( iso_object.mode == IsoObject.Mode.Mode3d ) {
-				var bounds3d = IsoObject3DBounds(iso_object);
-				var offset3d = iso_object.transform.position.z - bounds3d.center.z;
-				if ( iso_object.Internal.Bounds3d.extents != bounds3d.extents ||
-				     !Mathf.Approximately(iso_object.Internal.Offset3d, offset3d) )
+				var minmax3d = IsoObjectMinMax3D(iso_object);
+				var offset3d = iso_object.transform.position.z - minmax3d.center;
+				if ( !Mathf.Approximately(iso_object.Internal.Offset3d, offset3d) ||
+					iso_object.Internal.MinMax3d.Approximately(minmax3d) )
 				{
-					iso_object.Internal.Bounds3d = bounds3d;
 					iso_object.Internal.Offset3d = offset3d;
+					iso_object.Internal.MinMax3d = minmax3d;
 					return true;
 				}
 			}
 			return false;
 		}
-		
-		Bounds IsoObject3DBounds(IsoObject iso_object) {
-			var bounds = new Bounds();
+
+		IsoUtils.MinMax IsoObjectMinMax3D(IsoObject iso_object) {
 			iso_object.GetComponentsInChildren<Renderer>(_tmpRenderers);
-			if ( _tmpRenderers.Count > 0 ) {
-				bounds = _tmpRenderers[0].bounds;
-				for ( var i = 1; i < _tmpRenderers.Count; ++i ) {
-					bounds.Encapsulate(_tmpRenderers[i].bounds);
+			if  ( _tmpRenderers.Count < 1 ) {
+				return IsoUtils.MinMax.zero;
+			}
+			var bounds    = _tmpRenderers[0].bounds;
+			var center    = bounds.center.z;
+			var extent    = bounds.extents.z;
+			var minbounds = center - extent;
+			var maxbounds = center + extent;
+			var minmax = new IsoUtils.MinMax(center - extent, center + extent);
+			for ( int i = 1, e = _tmpRenderers.Count; i < e; ++i ) {
+				bounds    = _tmpRenderers[i].bounds;
+				center    = bounds.center.z;
+				extent    = bounds.extents.z;
+				minbounds = center - extent;
+				maxbounds = center + extent;
+				if ( minbounds < minmax.min ) {
+					minmax.min = minbounds;
+				}
+				if ( maxbounds > minmax.max ) {
+					minmax.max = maxbounds;
 				}
 			}
-			return bounds;
+			return minmax;
 		}
 
 		bool IsIsoObjectVisible(IsoObject iso_object) {
 			iso_object.GetComponentsInChildren<Renderer>(_tmpRenderers);
-			for ( var i = 0; i < _tmpRenderers.Count; ++i ) {
+			for ( int i = 0, e = _tmpRenderers.Count; i < e; ++i ) {
 				if ( _tmpRenderers[i].isVisible ) {
 					return true;
 				}
@@ -617,10 +632,9 @@ namespace IsoTools {
 			while ( self_depends_iter.MoveNext() ) {
 				depth = RecursivePlaceIsoObject(self_depends_iter.Current, depth);
 			}
-
 			if ( iso_object.mode == IsoObject.Mode.Mode3d ) {
 				var zoffset = iso_object.Internal.Offset3d;
-				var extents = iso_object.Internal.Bounds3d.extents.z;
+				var extents = iso_object.Internal.MinMax3d.size;
 				PlaceIsoObject(iso_object, depth + extents + zoffset);
 				return depth + extents * 2.0f + stepDepth;
 			} else {
diff --git a/Assets/IsoTools/Tiled/TiledMapProperties.cs b/Assets/IsoTools/Tiled/TiledMapProperties.cs
index c487ad9..069cdb5 100644
--- a/Assets/IsoTools/Tiled/TiledMapProperties.cs
+++ b/Assets/IsoTools/Tiled/TiledMapProperties.cs
@@ -24,7 +24,7 @@ namespace IsoTools.Tiled {
 
 		public bool Has(string property_name) {
 			if ( _properties != null ) {
-				for ( var i = 0; i < _properties.Count / 2; ++i ) {
+				for ( int i = 0, e = _properties.Count / 2; i < e; ++i ) {
 					if ( _properties[i * 2] == property_name ) {
 						return true;
 					}
@@ -165,7 +165,7 @@ namespace IsoTools.Tiled {
 
 		public bool TryGetAsString(string property_name, out string value) {
 			if ( _properties != null ) {
-				for ( var i = 0; i < _properties.Count / 2; ++i ) {
+				for ( int i = 0, e = _properties.Count / 2; i < e; ++i ) {
 					if ( _properties[i * 2] == property_name ) {
 						value = _properties[i * 2 + 1];
 						return true;