diff --git a/OpenRA.Mods.RA/Buildings/BibLayer.cs b/OpenRA.Mods.RA/Buildings/BibLayer.cs
index 121a2aecba..ce4711c1ea 100755
--- a/OpenRA.Mods.RA/Buildings/BibLayer.cs
+++ b/OpenRA.Mods.RA/Buildings/BibLayer.cs
@@ -10,6 +10,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.FileFormats;
 using OpenRA.Graphics;
@@ -21,14 +22,23 @@ namespace OpenRA.Mods.RA.Buildings
 	{
 		public readonly string[] BibTypes = { "bib3", "bib2", "bib1" };
 		public readonly int[] BibWidths = { 2, 3, 4 };
+		public readonly bool FrozenUnderFog = false;
 		public object Create(ActorInitializer init) { return new BibLayer(init.self, this); }
 	}
 
-	class BibLayer : IRenderOverlay, IWorldLoaded
+	struct CachedBib
+	{
+		public Dictionary<CPos, TileReference<byte, byte>> Tiles;
+		public IEnumerable<CPos> Footprint;
+		public bool Visible;
+	}
+
+	class BibLayer : IRenderOverlay, IWorldLoaded, ITickRender
 	{
 		World world;
 		BibLayerInfo info;
-		Dictionary<CPos, TileReference<byte, byte>> tiles;
+		Dictionary<Actor, CachedBib> visible;
+		Dictionary<Actor, CachedBib> dirty;
 		Sprite[][] bibSprites;
 
 		public BibLayer(Actor self, BibLayerInfo info)
@@ -43,7 +53,8 @@ namespace OpenRA.Mods.RA.Buildings
 		public void WorldLoaded(World w)
 		{
 			world = w;
-			tiles = new Dictionary<CPos, TileReference<byte, byte>>();
+			visible = new Dictionary<Actor, CachedBib>();
+			dirty = new Dictionary<Actor, CachedBib>();
 		}
 
 		public void DoBib(Actor b, bool isAdd)
@@ -55,40 +66,69 @@ namespace OpenRA.Mods.RA.Buildings
 			var size = buildingInfo.Dimensions.X;
 			var bibOffset = buildingInfo.Dimensions.Y - 1;
 
-			int bib = Array.IndexOf(info.BibWidths, size);
+			var bib = Array.IndexOf(info.BibWidths, size);
 			if (bib < 0)
 			{
 				Log.Write("debug", "Cannot bib {0}-wide building {1}", size, b.Info.Name);
 				return;
 			}
 
+			dirty[b] = new CachedBib()
+			{
+				Footprint = FootprintUtils.Tiles(b),
+				Tiles = new Dictionary<CPos, TileReference<byte, byte>>(),
+				Visible = isAdd
+			};
+
 			for (var i = 0; i < 2 * size; i++)
 			{
-				var p = b.Location + new CVec(i % size, i / size + bibOffset);
-				if (isAdd)
-					tiles[p] = new TileReference<byte, byte>((byte)(bib + 1), (byte)i);
-				else
-					tiles.Remove(p);
+				var cell = b.Location + new CVec(i % size, i / size + bibOffset);
+				var tile = new TileReference<byte, byte>((byte)(bib + 1), (byte) i);
+				dirty[b].Tiles.Add(cell, tile);
 			}
 		}
 
+		public void TickRender(WorldRenderer wr, Actor self)
+		{
+			var remove = new List<Actor>();
+			foreach (var kv in dirty)
+			{
+				if (!info.FrozenUnderFog || kv.Value.Footprint.Any(c => !self.World.FogObscures(c)))
+				{
+					if (kv.Value.Visible)
+						visible[kv.Key] = kv.Value;
+					else
+						visible.Remove(kv.Key);
+
+					remove.Add(kv.Key);
+				}
+			}
+
+			foreach (var r in remove)
+				dirty.Remove(r);
+		}
+
 		public void Render(WorldRenderer wr)
 		{
 			var pal = wr.Palette("terrain");
 			var cliprect = Game.viewport.WorldBounds(world);
 
-			foreach (var kv in tiles)
+			foreach (var bib in visible.Values)
 			{
-				if (!cliprect.Contains(kv.Key.X, kv.Key.Y))
-					continue;
-				if (world.ShroudObscures(kv.Key))
-					continue;
+				foreach (var kv in bib.Tiles)
+				{
+					if (!cliprect.Contains(kv.Key.X, kv.Key.Y))
+						continue;
+					if (world.ShroudObscures(kv.Key))
+						continue;
 
-				bibSprites[kv.Value.type - 1][kv.Value.index].DrawAt(kv.Key.ToPPos().ToFloat2(), pal);
+					var tile = bibSprites[kv.Value.type - 1][kv.Value.index];
+					tile.DrawAt(wr.ScreenPxPosition(kv.Key.CenterPosition) - 0.5f * tile.size, pal);
+				}
 			}
 		}
 	}
 
-	public class BibInfo : TraitInfo<Bib> { }
+	public class BibInfo : TraitInfo<Bib>, Requires<BuildingInfo> { }
 	public class Bib { }
 }
diff --git a/mods/d2k/rules/system.yaml b/mods/d2k/rules/system.yaml
index 639a37d593..0241c1bd2c 100644
--- a/mods/d2k/rules/system.yaml
+++ b/mods/d2k/rules/system.yaml
@@ -354,6 +354,7 @@ World:
 	BibLayer:
 		BibTypes: bib3x, bib2x
 		BibWidths: 3, 2
+		FrozenUnderFog: true
 	DomainIndex:
 	ResourceLayer:
 	ResourceClaimLayer: