diff --git a/.runConfigurations/Build TestPlugin.jar.run.xml b/.runConfigurations/Build TestPlugin.jar.run.xml
new file mode 100644
index 0000000..b2197ec
--- /dev/null
+++ b/.runConfigurations/Build TestPlugin.jar.run.xml	
@@ -0,0 +1,21 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Build TestPlugin.jar" type="GradleRunConfiguration" factoryName="Gradle">
+    <ExternalSystemSettings>
+      <option name="executionName" />
+      <option name="externalProjectPath" value="$PROJECT_DIR$/test-plugin" />
+      <option name="externalSystemIdString" value="GRADLE" />
+      <option name="scriptParameters" value="" />
+      <option name="taskDescriptions">
+        <list />
+      </option>
+      <option name="taskNames">
+        <list>
+          <option value="shadowJar" />
+        </list>
+      </option>
+      <option name="vmOptions" value="" />
+    </ExternalSystemSettings>
+    <GradleScriptDebugEnabled>true</GradleScriptDebugEnabled>
+    <method v="2" />
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/.runConfigurations/Run.run.xml b/.runConfigurations/Run.run.xml
index 46d06a7..bb0a744 100644
--- a/.runConfigurations/Run.run.xml
+++ b/.runConfigurations/Run.run.xml
@@ -10,6 +10,7 @@
     <option name="WORKING_DIRECTORY" value="" />
     <method v="2">
       <option name="Make" enabled="true" />
+      <option name="RunConfigurationTask" enabled="true" run_configuration_name="Build TestPlugin.jar" run_configuration_type="GradleRunConfiguration" />
     </method>
   </configuration>
 </component>
\ No newline at end of file
diff --git a/blokk-api/src/main/kotlin/space/blokk/world/block/BlockCodec.kt b/blokk-api/src/main/kotlin/space/blokk/world/block/BlockCodec.kt
index 4ebef1d..56c6ba2 100644
--- a/blokk-api/src/main/kotlin/space/blokk/world/block/BlockCodec.kt
+++ b/blokk-api/src/main/kotlin/space/blokk/world/block/BlockCodec.kt
@@ -32,6 +32,8 @@ class BlockCodec<T : Block> internal constructor(
             }
         })
 
+    val lastStateID get() = firstStateID + states.size
+
     class IllegalAttributeTargetType : Exception("The type of the target property is not allowed for attributes")
 
     fun getStateID(block: T): Int {
diff --git a/blokk-api/src/main/kotlin/space/blokk/world/block/Material.kt b/blokk-api/src/main/kotlin/space/blokk/world/block/Material.kt
index 9a4ff1a..231d565 100644
--- a/blokk-api/src/main/kotlin/space/blokk/world/block/Material.kt
+++ b/blokk-api/src/main/kotlin/space/blokk/world/block/Material.kt
@@ -14,6 +14,9 @@ interface Material<T : Block> {
     val collisionShape: CollisionShape
 
     companion object {
+        /**
+         * All materials, sorted by their numeric ID in ascending order.
+         */
         val all = GENERATED_BLOCKS
         val byID = GENERATED_BLOCKS.map { it.id to it }.toMap()
 
diff --git a/blokk-nbt/src/main/kotlin/space/blokk/nbt/NBT.kt b/blokk-nbt/src/main/kotlin/space/blokk/nbt/NBT.kt
index 6f890dd..8fe6f41 100644
--- a/blokk-nbt/src/main/kotlin/space/blokk/nbt/NBT.kt
+++ b/blokk-nbt/src/main/kotlin/space/blokk/nbt/NBT.kt
@@ -32,8 +32,9 @@ class NBT internal constructor(private val map: MutableMap<String, Any>) {
         map[name] = value
     }
 
-    fun write(destination: DataOutputStream, name: String) {
-        NBTCompound.writeNamedTag(destination, name, this)
+    fun write(destination: DataOutputStream, name: String? = null) {
+        if (name == null) NBTCompound.writeValue(destination, this)
+        else NBTCompound.writeNamedTag(destination, name, this)
     }
 
     fun toSNBT(pretty: Boolean) = NBTCompound.toSNBT(this, pretty)
diff --git a/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/ChunkDataPacketCodec.kt b/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/ChunkDataPacketCodec.kt
index 53469ca..3b53066 100644
--- a/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/ChunkDataPacketCodec.kt
+++ b/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/ChunkDataPacketCodec.kt
@@ -1,6 +1,8 @@
 package space.blokk.net.packet.play
 
 import io.netty.buffer.ByteBuf
+import io.netty.buffer.ByteBufOutputStream
+import io.netty.buffer.Unpooled
 import space.blokk.nbt.NBT
 import space.blokk.net.MinecraftProtocolDataTypes.writeVarInt
 import space.blokk.net.packet.OutgoingPacketCodec
@@ -9,19 +11,23 @@ import space.blokk.util.toCompactLongArray
 import space.blokk.world.block.Air
 import space.blokk.world.block.CaveAir
 import space.blokk.world.block.Material
+import space.blokk.world.block.material
+import java.io.DataOutputStream
+import kotlin.math.ceil
+import kotlin.math.log
 
 object ChunkDataPacketCodec : OutgoingPacketCodec<ChunkDataPacket>(0x22, ChunkDataPacket::class) {
-    private val nonAirHeightmapIgnoredBlocks = setOf(Air::class, CaveAir::class)
-    private val solidHeightmapIgnoredBlocks = Material.all.filter {
-        // TODO
-        true
-    }
+    private val airBlocks: Set<Material<*>> = setOf(Air, CaveAir)
+    private val nonSolidBlocks = Material.all.filter { it.collisionShape.isEmpty() }
+
+    private val numberOfBitsPerBlock = ceil(log(Material.all.last().codec.lastStateID.toDouble(), 2.0)).toInt()
 
     override fun ChunkDataPacket.encode(dst: ByteBuf) {
         dst.writeInt(key.x)
         dst.writeInt(key.z)
         dst.writeBoolean(true) // Full Chunk
 
+        // Bitmask
         var includedSections = 0
         data.sections.forEachIndexed { index, value ->
             if (value != null) includedSections = includedSections and (1 shl index)
@@ -29,10 +35,46 @@ object ChunkDataPacketCodec : OutgoingPacketCodec<ChunkDataPacket>(0x22, ChunkDa
 
         dst.writeVarInt(includedSections)
 
-        val heightmap = data.solidBlocksHeightmap ?: generateHeightmap(data.sections, listOf())
-
+        // Heightmaps
         val heightmaps = NBT()
-        heightmaps.set("MOTION_BLOCKING", heightmap.toCompactLongArray(9))
-        heightmaps.set("MOTION_BLOCKING", heightmap.toCompactLongArray(9))
+        heightmaps.set(
+            "MOTION_BLOCKING",
+            (data.solidBlocksHeightmap ?: generateHeightmap(
+                data.sections,
+                nonSolidBlocks
+            )).toCompactLongArray(9)
+        )
+
+        heightmaps.set(
+            "WORLD_SURFACE",
+            (data.nonAirBlocksHeightmap ?: generateHeightmap(
+                data.sections,
+                airBlocks
+            )).toCompactLongArray(9)
+        )
+
+        DataOutputStream(ByteBufOutputStream(dst)).use { heightmaps.write(it) }
+
+        // Biomes
+        data.biomes.forEach { dst.writeInt(it.numericID) }
+
+        // Blocks
+        val dataBuf = Unpooled.buffer() // TODO: Set an initial capacity
+        for (section in data.sections.filterNotNull()) {
+            val ids = section.map { it.material().codec.getStateID(it) }.toIntArray()
+            dataBuf.writeShort(ids.count { !(it == Air.codec.id || it == CaveAir.codec.id) })
+            dataBuf.writeByte(numberOfBitsPerBlock)
+
+            val array = ids.toCompactLongArray(numberOfBitsPerBlock)
+            dataBuf.writeVarInt(array.size)
+            array.forEach { dataBuf.writeLong(it) }
+        }
+
+        dst.writeVarInt(dataBuf.readableBytes())
+        dst.writeBytes(dataBuf)
+        dataBuf.release()
+
+        // Block entities
+        dst.writeVarInt(0)
     }
 }
diff --git a/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/PlayProtocol.kt b/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/PlayProtocol.kt
index a785975..331b30f 100644
--- a/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/PlayProtocol.kt
+++ b/blokk-packet-codecs/src/main/kotlin/space/blokk/net/packet/play/PlayProtocol.kt
@@ -5,6 +5,7 @@ import space.blokk.net.packet.Protocol
 object PlayProtocol : Protocol(
     "PLAY",
     ClientSettingsPacketCodec,
+    ChunkDataPacketCodec,
     DeclareRecipesPacketCodec,
     DisconnectPacketCodec,
     IncomingPluginMessagePacketCodec,
diff --git a/blokk-server/build.gradle.kts b/blokk-server/build.gradle.kts
index 3953e91..34a5df3 100644
--- a/blokk-server/build.gradle.kts
+++ b/blokk-server/build.gradle.kts
@@ -61,8 +61,10 @@ tasks {
 
         @Suppress("UnstableApiUsage")
         manifest {
-            this.attributes("Main-Class" to "space.blokk.BlokkServer")
-            this.attributes("Implementation-Version" to project.version)
+            this.attributes(
+                "Main-Class" to "space.blokk.BlokkServer",
+                "Implementation-Version" to project.version
+            )
         }
     }
 }
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 1c62c9f..2022560 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -12,3 +12,4 @@ include(":blokk-nbt")
 include(":blokk-packet-codecs")
 include(":blokk-packets")
 include(":blokk-server")
+include("test-plugin")
diff --git a/test-plugin/build.gradle.kts b/test-plugin/build.gradle.kts
new file mode 100644
index 0000000..2754e16
--- /dev/null
+++ b/test-plugin/build.gradle.kts
@@ -0,0 +1,22 @@
+plugins {
+    kotlin("jvm")
+    id("com.github.johnrengelman.shadow") version "6.1.0"
+}
+
+group = "space.blokk.testplugin"
+version = "0.0.1-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation(project(":blokk-api"))
+}
+
+tasks {
+    shadowJar {
+        archiveFileName.set("TestPlugin.jar")
+        destinationDirectory.set(file("../serverData/plugins"))
+    }
+}
diff --git a/test-plugin/src/main/kotlin/space/blokk/testplugin/TestPlugin.kt b/test-plugin/src/main/kotlin/space/blokk/testplugin/TestPlugin.kt
new file mode 100644
index 0000000..679b907
--- /dev/null
+++ b/test-plugin/src/main/kotlin/space/blokk/testplugin/TestPlugin.kt
@@ -0,0 +1,25 @@
+package space.blokk.testplugin
+
+import space.blokk.Blokk
+import space.blokk.event.EventHandler
+import space.blokk.event.Listener
+import space.blokk.net.event.SessionAfterLoginEvent
+import space.blokk.plugin.Plugin
+import space.blokk.world.*
+import space.blokk.testplugin.anvil.AnvilWorld
+import space.blokk.world.block.GrassBlock
+
+class TestPlugin: Plugin("Test", "1.0.0") {
+    override fun onEnable() {
+        val world = AnvilWorld(WorldDimension.OVERWORLD, WorldType.FLAT)
+        world.getVoxel(VoxelLocation(0, 2, 0)).block = GrassBlock(Unit)
+
+        Blokk.sessions.registerListener(object : Listener {
+            @EventHandler
+            fun onSessionAfterLogin(event: SessionAfterLoginEvent) {
+                event.initialWorldAndLocation =
+                    WorldAndLocationWithRotation(world, LocationWithRotation(0.0, 4.0, 0.0, 0f, 0f))
+            }
+        })
+    }
+}
diff --git a/blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilChunk.kt b/test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilChunk.kt
similarity index 97%
rename from blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilChunk.kt
rename to test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilChunk.kt
index fac4680..f38a801 100644
--- a/blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilChunk.kt
+++ b/test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilChunk.kt
@@ -1,4 +1,4 @@
-package space.blokk.world.anvil
+package space.blokk.testplugin.anvil
 
 import com.google.common.cache.LoadingCache
 import space.blokk.player.Player
diff --git a/blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilVoxel.kt b/test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilVoxel.kt
similarity index 97%
rename from blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilVoxel.kt
rename to test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilVoxel.kt
index a7de44a..b2ef75b 100644
--- a/blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilVoxel.kt
+++ b/test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilVoxel.kt
@@ -1,4 +1,4 @@
-package space.blokk.world.anvil
+package space.blokk.testplugin.anvil
 
 import space.blokk.world.Chunk
 import space.blokk.world.Voxel
diff --git a/blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilWorld.kt b/test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilWorld.kt
similarity index 96%
rename from blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilWorld.kt
rename to test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilWorld.kt
index 886a7ed..65ea274 100644
--- a/blokk-server/src/main/kotlin/space/blokk/world/anvil/AnvilWorld.kt
+++ b/test-plugin/src/main/kotlin/space/blokk/testplugin/anvil/AnvilWorld.kt
@@ -1,4 +1,4 @@
-package space.blokk.world.anvil
+package space.blokk.testplugin.anvil
 
 import com.google.common.cache.CacheBuilder
 import com.google.common.cache.CacheLoader
diff --git a/test-plugin/src/main/resources/plugin_class.txt b/test-plugin/src/main/resources/plugin_class.txt
new file mode 100644
index 0000000..f7dff21
--- /dev/null
+++ b/test-plugin/src/main/resources/plugin_class.txt
@@ -0,0 +1 @@
+space.blokk.testplugin.TestPlugin