diff --git a/OpenRA.Game/Traits/World/ActorMap.cs b/OpenRA.Game/Traits/World/ActorMap.cs
index 9a19b9c02d..b181c26297 100644
--- a/OpenRA.Game/Traits/World/ActorMap.cs
+++ b/OpenRA.Game/Traits/World/ActorMap.cs
@@ -98,22 +98,26 @@ namespace OpenRA.Traits
 
 			WPos position;
 			WDist range;
+			WDist vRange;
+
 			IEnumerable<Actor> currentActors = Enumerable.Empty<Actor>();
 
-			public ProximityTrigger(WPos pos, WDist range, Action<Actor> onActorEntered, Action<Actor> onActorExited)
+			public ProximityTrigger(WPos pos, WDist range, WDist vRange, Action<Actor> onActorEntered, Action<Actor> onActorExited)
 			{
 				this.onActorEntered = onActorEntered;
 				this.onActorExited = onActorExited;
 
-				Update(pos, range);
+				Update(pos, range, vRange);
 			}
 
-			public void Update(WPos newPos, WDist newRange)
+			public void Update(WPos newPos, WDist newRange, WDist newVRange)
 			{
 				position = newPos;
 				range = newRange;
+				vRange = newVRange;
+
+				var offset = new WVec(newRange, newRange, newVRange);
 
-				var offset = new WVec(newRange, newRange, WDist.Zero);
 				TopLeft = newPos - offset;
 				BottomRight = newPos + offset;
 
@@ -128,7 +132,8 @@ namespace OpenRA.Traits
 				var oldActors = currentActors;
 				var delta = new WVec(range, range, WDist.Zero);
 				currentActors = am.ActorsInBox(position - delta, position + delta)
-					.Where(a => (a.CenterPosition - position).HorizontalLengthSquared < range.LengthSquared)
+					.Where(a => (a.CenterPosition - position).HorizontalLengthSquared < range.LengthSquared
+						&& (vRange.Length == 0 || (a.World.Map.DistanceAboveTerrain(a.CenterPosition).LengthSquared <= vRange.LengthSquared)))
 					.ToList();
 
 				var entered = currentActors.Except(oldActors);
@@ -439,10 +444,10 @@ namespace OpenRA.Traits
 			}
 		}
 
-		public int AddProximityTrigger(WPos pos, WDist range, Action<Actor> onEntry, Action<Actor> onExit)
+		public int AddProximityTrigger(WPos pos, WDist range, WDist vRange, Action<Actor> onEntry, Action<Actor> onExit)
 		{
 			var id = nextTriggerId++;
-			var t = new ProximityTrigger(pos, range, onEntry, onExit);
+			var t = new ProximityTrigger(pos, range, vRange, onEntry, onExit);
 			proximityTriggers.Add(id, t);
 
 			foreach (var bin in BinsInBox(t.TopLeft, t.BottomRight))
@@ -463,7 +468,7 @@ namespace OpenRA.Traits
 			t.Dispose();
 		}
 
-		public void UpdateProximityTrigger(int id, WPos newPos, WDist newRange)
+		public void UpdateProximityTrigger(int id, WPos newPos, WDist newRange, WDist newVRange)
 		{
 			ProximityTrigger t;
 			if (!proximityTriggers.TryGetValue(id, out t))
@@ -472,7 +477,7 @@ namespace OpenRA.Traits
 			foreach (var bin in BinsInBox(t.TopLeft, t.BottomRight))
 				bin.ProximityTriggers.Remove(t);
 
-			t.Update(newPos, newRange);
+			t.Update(newPos, newRange, newVRange);
 
 			foreach (var bin in BinsInBox(t.TopLeft, t.BottomRight))
 				bin.ProximityTriggers.Add(t);
diff --git a/OpenRA.Mods.Common/Scripting/Global/TriggerGlobal.cs b/OpenRA.Mods.Common/Scripting/Global/TriggerGlobal.cs
index aa034cd795..ef7120cc0d 100644
--- a/OpenRA.Mods.Common/Scripting/Global/TriggerGlobal.cs
+++ b/OpenRA.Mods.Common/Scripting/Global/TriggerGlobal.cs
@@ -373,7 +373,7 @@ namespace OpenRA.Mods.Common.Scripting
 				}
 			};
 
-			triggerId = Context.World.ActorMap.AddProximityTrigger(pos, range, invokeEntry, null);
+			triggerId = Context.World.ActorMap.AddProximityTrigger(pos, range, WDist.Zero, invokeEntry, null);
 
 			return triggerId;
 		}
@@ -400,7 +400,7 @@ namespace OpenRA.Mods.Common.Scripting
 				}
 			};
 
-			triggerId = Context.World.ActorMap.AddProximityTrigger(pos, range, null, invokeExit);
+			triggerId = Context.World.ActorMap.AddProximityTrigger(pos, range, WDist.Zero, null, invokeExit);
 
 			return triggerId;
 		}
diff --git a/OpenRA.Mods.Common/Traits/ProximityCapturable.cs b/OpenRA.Mods.Common/Traits/ProximityCapturable.cs
index dd3100d8ec..bae826e072 100644
--- a/OpenRA.Mods.Common/Traits/ProximityCapturable.cs
+++ b/OpenRA.Mods.Common/Traits/ProximityCapturable.cs
@@ -67,7 +67,7 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			// TODO: Eventually support CellTriggers as well
-			proximityTrigger = self.World.ActorMap.AddProximityTrigger(self.CenterPosition, Info.Range, ActorEntered, ActorLeft);
+			proximityTrigger = self.World.ActorMap.AddProximityTrigger(self.CenterPosition, Info.Range, WDist.Zero, ActorEntered, ActorLeft);
 		}
 
 		void INotifyRemovedFromWorld.RemovedFromWorld(Actor self)
@@ -84,7 +84,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (!self.IsInWorld || self.CenterPosition == prevPosition)
 				return;
 
-			self.World.ActorMap.UpdateProximityTrigger(proximityTrigger, self.CenterPosition, Info.Range);
+			self.World.ActorMap.UpdateProximityTrigger(proximityTrigger, self.CenterPosition, Info.Range, WDist.Zero);
 			prevPosition = self.CenterPosition;
 		}
 
diff --git a/OpenRA.Mods.Common/Traits/Upgrades/UpgradeActorsNear.cs b/OpenRA.Mods.Common/Traits/Upgrades/UpgradeActorsNear.cs
index 92031b42d6..c4907c0327 100644
--- a/OpenRA.Mods.Common/Traits/Upgrades/UpgradeActorsNear.cs
+++ b/OpenRA.Mods.Common/Traits/Upgrades/UpgradeActorsNear.cs
@@ -57,7 +57,7 @@ namespace OpenRA.Mods.Common.Traits
 		public void AddedToWorld(Actor self)
 		{
 			cachedPosition = self.CenterPosition;
-			proximityTrigger = self.World.ActorMap.AddProximityTrigger(cachedPosition, cachedRange, ActorEntered, ActorExited);
+			proximityTrigger = self.World.ActorMap.AddProximityTrigger(cachedPosition, cachedRange, WDist.Zero, ActorEntered, ActorExited);
 		}
 
 		public void RemovedFromWorld(Actor self)
@@ -80,7 +80,7 @@ namespace OpenRA.Mods.Common.Traits
 			{
 				cachedPosition = self.CenterPosition;
 				cachedRange = desiredRange;
-				self.World.ActorMap.UpdateProximityTrigger(proximityTrigger, cachedPosition, cachedRange);
+				self.World.ActorMap.UpdateProximityTrigger(proximityTrigger, cachedPosition, cachedRange, WDist.Zero);
 			}
 		}