diff --git a/doc/rendering/world_renderer.md b/doc/rendering/world_renderer.md
index b3785a04f..ea25adb3c 100644
--- a/doc/rendering/world_renderer.md
+++ b/doc/rendering/world_renderer.md
@@ -45,6 +45,5 @@
 - ToDo:
   - Build biome cache only in render distance
   - Update neighbour chunks if needed
-  - Reduce memory usage
   - Unload on minimize
   - Biomes: Check if chunk is single biome
diff --git a/src/main/java/de/bixilon/minosoft/data/world/World.kt b/src/main/java/de/bixilon/minosoft/data/world/World.kt
index 89e58925f..2c66f7585 100644
--- a/src/main/java/de/bixilon/minosoft/data/world/World.kt
+++ b/src/main/java/de/bixilon/minosoft/data/world/World.kt
@@ -37,13 +37,14 @@ import de.bixilon.minosoft.modding.event.events.ChunkDataChangeEvent
 import de.bixilon.minosoft.modding.event.events.ChunkUnloadEvent
 import de.bixilon.minosoft.protocol.network.connection.play.PlayConnection
 import de.bixilon.minosoft.protocol.protocol.ProtocolDefinition
-import de.bixilon.minosoft.util.KUtil.synchronizedMapOf
+import de.bixilon.minosoft.util.KUtil.lockMapOf
 import de.bixilon.minosoft.util.KUtil.toSynchronizedMap
 import de.bixilon.minosoft.util.MMath
+import de.bixilon.minosoft.util.ReadWriteLock
 import de.bixilon.minosoft.util.chunk.ChunkUtil.canBuildBiomeCache
 import de.bixilon.minosoft.util.chunk.ChunkUtil.getChunkNeighbourPositions
 import de.bixilon.minosoft.util.chunk.ChunkUtil.received
-import de.bixilon.minosoft.util.collections.SynchronizedMap
+import de.bixilon.minosoft.util.collections.LockMap
 import glm_.func.common.clamp
 import glm_.vec2.Vec2i
 import glm_.vec3.Vec3
@@ -59,8 +60,9 @@ import kotlin.random.Random
 class World(
     val connection: PlayConnection,
 ) : BiomeAccessor {
+    val lock = ReadWriteLock()
     var cacheBiomeAccessor: NoiseBiomeAccessor? = null
-    val chunks: SynchronizedMap<Vec2i, Chunk> = synchronizedMapOf()
+    val chunks: LockMap<Vec2i, Chunk> = lockMapOf()
     val entities = WorldEntities()
     var hardcore = false
     var dimension: DimensionProperties? = null
diff --git a/src/main/java/de/bixilon/minosoft/data/world/container/RegistrySectionDataProvider.kt b/src/main/java/de/bixilon/minosoft/data/world/container/RegistrySectionDataProvider.kt
index abb8f29bd..58597a13e 100644
--- a/src/main/java/de/bixilon/minosoft/data/world/container/RegistrySectionDataProvider.kt
+++ b/src/main/java/de/bixilon/minosoft/data/world/container/RegistrySectionDataProvider.kt
@@ -23,7 +23,7 @@ class RegistrySectionDataProvider<T>(
 ) : SectionDataProvider<T>(data, checkSize = checkSize) {
 
     @Suppress("UNCHECKED_CAST")
-    fun setIdData(ids: Array<Int>) {
+    fun setIdData(ids: IntArray) {
         val data: Array<Any?> = arrayOfNulls(ProtocolDefinition.BLOCKS_PER_SECTION)
 
         for ((index, id) in ids.withIndex()) {
diff --git a/src/main/java/de/bixilon/minosoft/gui/rendering/RenderWindow.kt b/src/main/java/de/bixilon/minosoft/gui/rendering/RenderWindow.kt
index c5c14e44c..1dc061441 100644
--- a/src/main/java/de/bixilon/minosoft/gui/rendering/RenderWindow.kt
+++ b/src/main/java/de/bixilon/minosoft/gui/rendering/RenderWindow.kt
@@ -83,8 +83,8 @@ class RenderWindow(
     private var lastFrame = 0.0
     private val latch = CountUpAndDownLatch(1)
 
-    private var renderingState = RenderingStates.RUNNING
-        set(value) {
+    var renderingState = RenderingStates.RUNNING
+        private set(value) {
             if (field == value) {
                 return
             }
diff --git a/src/main/java/de/bixilon/minosoft/gui/rendering/block/WorldRenderer.kt b/src/main/java/de/bixilon/minosoft/gui/rendering/block/WorldRenderer.kt
index d571c2fc4..09ea9558a 100644
--- a/src/main/java/de/bixilon/minosoft/gui/rendering/block/WorldRenderer.kt
+++ b/src/main/java/de/bixilon/minosoft/gui/rendering/block/WorldRenderer.kt
@@ -13,6 +13,9 @@
 
 package de.bixilon.minosoft.gui.rendering.block
 
+import de.bixilon.minosoft.config.key.KeyAction
+import de.bixilon.minosoft.config.key.KeyBinding
+import de.bixilon.minosoft.config.key.KeyCodes
 import de.bixilon.minosoft.data.assets.AssetsUtil
 import de.bixilon.minosoft.data.assets.Resources
 import de.bixilon.minosoft.data.direction.Directions
@@ -23,11 +26,13 @@ import de.bixilon.minosoft.data.world.World
 import de.bixilon.minosoft.gui.rendering.RenderWindow
 import de.bixilon.minosoft.gui.rendering.Renderer
 import de.bixilon.minosoft.gui.rendering.RendererBuilder
+import de.bixilon.minosoft.gui.rendering.RenderingStates
 import de.bixilon.minosoft.gui.rendering.block.mesh.ChunkSectionMesh
 import de.bixilon.minosoft.gui.rendering.block.mesh.ChunkSectionMeshes
 import de.bixilon.minosoft.gui.rendering.block.preparer.AbstractSectionPreparer
 import de.bixilon.minosoft.gui.rendering.block.preparer.CullSectionPreparer
 import de.bixilon.minosoft.gui.rendering.modding.events.FrustumChangeEvent
+import de.bixilon.minosoft.gui.rendering.modding.events.RenderingStateChangeEvent
 import de.bixilon.minosoft.gui.rendering.models.ModelLoader
 import de.bixilon.minosoft.gui.rendering.system.base.RenderSystem
 import de.bixilon.minosoft.gui.rendering.system.base.phases.OpaqueDrawable
@@ -222,6 +227,31 @@ class WorldRenderer(
 
         connection.registerEvent(CallbackEventInvoker.of<ChunkUnloadEvent> { unloadChunk(it.chunkPosition) })
         connection.registerEvent(CallbackEventInvoker.of<PlayConnectionStateChangeEvent> { if (it.state == PlayConnectionStates.DISCONNECTED) unloadWorld() })
+        connection.registerEvent(CallbackEventInvoker.of<RenderingStateChangeEvent> {
+            if (it.state == RenderingStates.PAUSED) {
+                unloadWorld()
+            } else if (it.previousState == RenderingStates.PAUSED) {
+                prepareWorld()
+            }
+        })
+
+        renderWindow.inputHandler.registerKeyCallback("minosoft:clear_chunk_cache".toResourceLocation(), KeyBinding(
+            mutableMapOf(
+                KeyAction.MODIFIER to mutableSetOf(KeyCodes.KEY_F3),
+                KeyAction.PRESS to mutableSetOf(KeyCodes.KEY_A),
+            ),
+        )) {
+            unloadWorld()
+            prepareWorld()
+        }
+    }
+
+    private fun prepareWorld() {
+        world.lock.acquire()
+        for ((chunkPosition, chunk) in world.chunks) {
+            queueChunk(chunkPosition, chunk)
+        }
+        world.lock.release()
     }
 
     private fun unloadWorld() {
@@ -402,7 +432,7 @@ class WorldRenderer(
     }
 
     private fun queueSection(chunkPosition: Vec2i, sectionHeight: Int, chunk: Chunk? = world.chunks[chunkPosition], section: ChunkSection? = chunk?.get(sectionHeight), ignoreFrustum: Boolean = false) {
-        if (chunk == null || section == null) {
+        if (chunk == null || section == null || renderWindow.renderingState == RenderingStates.PAUSED) {
             return
         }
         val queued = internalQueueSection(chunkPosition, sectionHeight, chunk, section, ignoreFrustum)
@@ -414,7 +444,7 @@ class WorldRenderer(
     }
 
     private fun queueChunk(chunkPosition: Vec2i, chunk: Chunk = world.chunks[chunkPosition]!!) {
-        if (!chunk.isFullyLoaded) {
+        if (!chunk.isFullyLoaded || renderWindow.renderingState == RenderingStates.PAUSED) {
             return
         }
 
diff --git a/src/main/java/de/bixilon/minosoft/gui/rendering/models/unbaked/block/UnbakedBlockStateModel.kt b/src/main/java/de/bixilon/minosoft/gui/rendering/models/unbaked/block/UnbakedBlockStateModel.kt
index bea477367..fcc621714 100644
--- a/src/main/java/de/bixilon/minosoft/gui/rendering/models/unbaked/block/UnbakedBlockStateModel.kt
+++ b/src/main/java/de/bixilon/minosoft/gui/rendering/models/unbaked/block/UnbakedBlockStateModel.kt
@@ -99,10 +99,13 @@ data class UnbakedBlockStateModel(
                 }
 
                 var direction = face.direction
+                var cullFace = face.cullFace
                 rotation?.let {
                     val rad = it.rad
 
                     direction = Directions.byDirection(Vec3(face.direction.vectorf).apply { rotateAssign(rad) })
+                    cullFace = face.cullFace?.vectorf?.let { cullFace -> Directions.byDirection(Vec3(cullFace).apply { rotateAssign(rad) }) }
+
                     for ((index, position) in positions.withIndex()) {
                         positions[index] = Vec3(position).apply { rotateAssign(rad, true) }
                     }
@@ -147,7 +150,7 @@ data class UnbakedBlockStateModel(
                     uv = texturePositions,
                     shade = shade,
                     tintIndex = face.tintIndex,
-                    cullFace = face.cullFace,
+                    cullFace = cullFace,
                     texture = texture,
                     touching = touching,
                 )
diff --git a/src/main/java/de/bixilon/minosoft/gui/rendering/particle/types/render/texture/TextureParticle.kt b/src/main/java/de/bixilon/minosoft/gui/rendering/particle/types/render/texture/TextureParticle.kt
index d11c449d1..1ca6ca278 100644
--- a/src/main/java/de/bixilon/minosoft/gui/rendering/particle/types/render/texture/TextureParticle.kt
+++ b/src/main/java/de/bixilon/minosoft/gui/rendering/particle/types/render/texture/TextureParticle.kt
@@ -25,10 +25,10 @@ abstract class TextureParticle(connection: PlayConnection, position: Vec3d, velo
     abstract val texture: AbstractTexture?
 
 
-    override fun addVertex(transparentMesh: ParticleMesh, translucentMesh: ParticleMesh, time:Long) {
+    override fun addVertex(transparentMesh: ParticleMesh, particleMesh: ParticleMesh, time: Long) {
         val texture = texture ?: return
         when {
-            texture.transparency == TextureTransparencies.TRANSLUCENT || color.alpha != 255 -> translucentMesh
+            texture.transparency == TextureTransparencies.TRANSLUCENT || color.alpha != 255 -> particleMesh
             else -> transparentMesh
         }.addVertex(getCameraPosition(time), scale, texture, color)
     }
diff --git a/src/main/java/de/bixilon/minosoft/util/KUtil.kt b/src/main/java/de/bixilon/minosoft/util/KUtil.kt
index 3779954e9..9c64d7f29 100644
--- a/src/main/java/de/bixilon/minosoft/util/KUtil.kt
+++ b/src/main/java/de/bixilon/minosoft/util/KUtil.kt
@@ -85,6 +85,10 @@ object KUtil {
         }
     }
 
+    fun <K, V> lockMapOf(vararg pairs: Pair<K, V>): LockMap<K, V> {
+        return LockMap(mutableMapOf(*pairs))
+    }
+
     fun <K, V> synchronizedMapOf(vararg pairs: Pair<K, V>): SynchronizedMap<K, V> {
         return SynchronizedMap(mutableMapOf(*pairs))
     }