diff --git a/webclient/src/App.tsx b/webclient/src/App.tsx
index 8630c58..46bfece 100644
--- a/webclient/src/App.tsx
+++ b/webclient/src/App.tsx
@@ -2,10 +2,10 @@ import { BrowserRouter, Link, Outlet, Route, Routes, useLocation, useNavigate, u
 import { VoxelEditorPage } from './components/voxelEditor/VoxelEditorPage';
 import { useEffect, useLayoutEffect, useRef } from 'react';
 import { reaction } from 'mobx';
-import { ThreeView } from './components/ThreeView';
 import { state } from './state';
 import './App.scss';
 import { Panels } from './components/Panels';
+import { LayeredThreeView } from './components/layers/LayeredThreeView';
 
 function StateToUrlSync() {
     const navigate = useNavigate();
@@ -94,7 +94,7 @@ function EditorLayout() {
     return (
         <>
             <Outlet />
-            <ThreeView />
+            <LayeredThreeView />
             <Panels />
         </>
     );
diff --git a/webclient/src/components/DebugLabel.tsx b/webclient/src/components/DebugLabel.tsx
index 391acb8..6178c74 100644
--- a/webclient/src/components/DebugLabel.tsx
+++ b/webclient/src/components/DebugLabel.tsx
@@ -2,13 +2,13 @@ import { Html } from "@react-three/drei";
 import { useFrame } from "@react-three/fiber";
 import { useRef } from "react";
 import * as THREE from "three";
-import type { RuntimeObjectInstance } from "../types";
 import { debugLabelsStore } from "../state/debugLabelsState";
 import { state } from "../state";
 import { observer } from "mobx-react-lite";
 import { formatV3 } from "../utils";
+import type { ObjectInstance } from "../types";
 
-export const DebugLabel = observer(function ({ obj }: { obj: RuntimeObjectInstance; }) {
+export const DebugLabel = observer(function ({ obj }: { obj: ObjectInstance; }) {
     const groupRef = useRef<THREE.Group>(null);
 
     const rb = obj.rb();
diff --git a/webclient/src/components/DebugLabelsView.tsx b/webclient/src/components/DebugLabelsView.tsx
index bd8f6d0..1d84431 100644
--- a/webclient/src/components/DebugLabelsView.tsx
+++ b/webclient/src/components/DebugLabelsView.tsx
@@ -2,9 +2,8 @@ import { useEffect } from "react";
 import { observer } from "mobx-react-lite";
 import { debugLabelsStore } from "../state/debugLabelsState";
 import { DebugLabel } from "./DebugLabel";
-import type { RuntimeScene } from "../types";
 
-export const DebugLabelsView = observer(function ({ scene, editMode }: { scene: RuntimeScene, editMode?: boolean }) {
+export const DebugLabelsView = observer(function ({ scene, editMode }: { scene: Scene, editMode?: boolean }) {
     useEffect(
         () => {
             return () => { debugLabelsStore.clear(); };
diff --git a/webclient/src/components/GameObjectView.tsx b/webclient/src/components/GameObjectView.tsx
index f385819..2f7e392 100644
--- a/webclient/src/components/GameObjectView.tsx
+++ b/webclient/src/components/GameObjectView.tsx
@@ -1,11 +1,10 @@
 import { observer } from "mobx-react-lite";
-import type { RuntimeGameObjectInstance } from "../types";
 import { state } from "../state";
 import { ObjectViewInternal } from "./ObjectViewInternal";
 import { PlayerObjectView } from "./CharacterView";
 
 export type GameObjectViewProps = {
-    object: RuntimeGameObjectInstance;
+    object: ObjectInstance;
     isPlayer: boolean;
     isSceneEditor?: boolean;
 }
@@ -16,7 +15,7 @@ export const GameObjectView = observer(function (props: GameObjectViewProps) {
         return null;
 
     if (props.isPlayer)
-        return <PlayerObjectView object={props.object as RuntimeGameObjectInstance} objectType={objectType} />;
+        return <PlayerObjectView object={props.object} objectType={objectType} />;
 
     function handleClick(): void {
         state.game?.emitEvent('objectClicked', { object: props.object });
diff --git a/webclient/src/components/ObjectEditorView.tsx b/webclient/src/components/ObjectEditorView.tsx
index 8528020..afb299f 100644
--- a/webclient/src/components/ObjectEditorView.tsx
+++ b/webclient/src/components/ObjectEditorView.tsx
@@ -1,6 +1,6 @@
 import { observer } from "mobx-react-lite";
 import { runInAction } from "mobx";
-import type { ObjectInstance, R3, Runtime } from "../types";
+import type { ObjectInstance, R3 } from "../types";
 import { useMemo, useRef, useEffect, useCallback, type RefObject } from "react";
 import type { Group } from "three";
 import { Euler, Quaternion, Vector3, BoxHelper, type LineBasicMaterial } from "three";
@@ -11,7 +11,7 @@ import { nextObjectEditMode } from "../state/worldEditorState";
 import { ObjectViewInternal, type ObjectViewInternalHandle } from "./ObjectViewInternal";
 
 type ObjectEditorViewProps = {
-    object: Runtime<ObjectInstance>;
+    object: ObjectInstance;
     isPlayer: boolean;
 }
 
diff --git a/webclient/src/components/ObjectViewInternal.tsx b/webclient/src/components/ObjectViewInternal.tsx
index 3b982c6..afd0eac 100644
--- a/webclient/src/components/ObjectViewInternal.tsx
+++ b/webclient/src/components/ObjectViewInternal.tsx
@@ -1,4 +1,4 @@
-import type { ObjectType, RuntimeGameObjectInstance, RuntimeObjectInstance } from "../types";
+import type { ObjectInstance, ObjectType, RuntimeGameObjectInstance, RuntimeObjectInstance } from "../types";
 import type { VoxelGroup } from "../types/runtime/voxelGroup";
 import { useEffect, useImperativeHandle, useRef, type Ref, memo, useMemo } from "react";
 import { Euler, Quaternion, Mesh, MeshStandardMaterial, type Group } from "three";
@@ -8,10 +8,10 @@ import { SyncRigidBody } from "./SyncRigidBody";
 import { reaction, runInAction } from "mobx";
 import { v3toRapier } from "../utils";
 import { state } from "../state";
-import { buildVoxelMesh } from "../utils/graphics/voxelMesh";
+import { buildVoxelGroupMesh } from "../utils/graphics/voxelMesh";
 
 const VoxelGroupMesh = memo(function VoxelGroupMesh({ vg, opacity }: { vg: VoxelGroup, opacity: number }) {
-    const geo = useMemo(() => buildVoxelMesh(vg.positions), [vg]);
+    const geo = useMemo(() => buildVoxelGroupMesh(vg.positions), [vg]);
     useEffect(() => () => { geo.dispose(); }, [geo]);
 
     const op = vg.opacity * opacity;
@@ -29,7 +29,7 @@ export type ObjectViewInternalHandle = {
 }
 
 type ObjectViewInternalProps = {
-    object: Omit<RuntimeObjectInstance, 'typeId'>;
+    object: Omit<ObjectInstance, 'typeId'>;
     objectType: ObjectType;
     editMode?: boolean;
     isPlayer?: boolean;
@@ -54,19 +54,17 @@ export const ObjectViewInternal = function ({ object, objectType, ref, ...props
                     if (!rbRef.current)
                         return;
 
-                    const gameObj = object as RuntimeGameObjectInstance;
+                    rbRef.current.setTranslation(v3toRapier(object.position), true);
 
-                    rbRef.current.setTranslation(v3toRapier(gameObj.position), true);
-
-                    const euler = new Euler(gameObj.rotation[0], gameObj.rotation[1], gameObj.rotation[2]);
+                    const euler = new Euler(...object.rotation);
                     const q = new Quaternion().setFromEuler(euler);
                     rbRef.current.setRotation({ x: q.x, y: q.y, z: q.z, w: q.w }, true);
 
-                    groupRef.current?.scale.set(...gameObj.scale);
+                    groupRef.current?.scale.set(...object.scale);
 
-                    rbRef.current.setLinvel(v3toRapier(gameObj.linearVelocity), true);
+                    rbRef.current.setLinvel(v3toRapier(object.linearVelocity), true);
 
-                    rbRef.current.setAngvel(v3toRapier(gameObj.angularVelocity), true);
+                    rbRef.current.setAngvel(v3toRapier(object.angularVelocity), true);
                 },
             );
         },
@@ -141,8 +139,8 @@ export const ObjectViewInternal = function ({ object, objectType, ref, ...props
                     object.position = data.position;
                     object.rotation = data.rotation;
                     if (!props.editMode) {
-                        (object as RuntimeGameObjectInstance).linearVelocity = data.linearVelocity;
-                        (object as RuntimeGameObjectInstance).angularVelocity = data.radialVelocity;
+                        (object as ObjectInstance).linearVelocity = data.linearVelocity;
+                        (object as ObjectInstance).angularVelocity = data.radialVelocity;
                     }
                     // do not change object.version to not trigger rerender
                 });
@@ -154,7 +152,7 @@ export const ObjectViewInternal = function ({ object, objectType, ref, ...props
                 scale={object.scale}
                 onClick={handleClick}
             >
-                {
+                {/* {
                     object.cache.voxelGroups.map((vg) =>
                         <VoxelGroupMesh
                             key={`${vg.id}-${object.cache.updatedAt}`}
@@ -163,7 +161,7 @@ export const ObjectViewInternal = function ({ object, objectType, ref, ...props
                         />
                     )
                 }
-                {object.cache.colliderMesh && <ConvexHullCollider args={[object.cache.colliderMesh[0]]} />}
+                {object.cache.colliderMesh && <ConvexHullCollider args={[object.cache.colliderMesh[0]]} />} */}
             </group>
         </SyncRigidBody>
     );
diff --git a/webclient/src/components/SceneEditorView.tsx b/webclient/src/components/SceneEditorView.tsx
index 5e04b94..aee90a1 100644
--- a/webclient/src/components/SceneEditorView.tsx
+++ b/webclient/src/components/SceneEditorView.tsx
@@ -1,6 +1,6 @@
 import { Suspense, useRef } from 'react';
 import type React from 'react';
-import { Grid, OrbitControls } from '@react-three/drei';
+import { OrbitControls } from '@react-three/drei';
 import { observer } from 'mobx-react-lite';
 import { state } from '../state';
 import { SceneView } from './SceneView';
diff --git a/webclient/src/components/SceneView.tsx b/webclient/src/components/SceneView.tsx
index 348d204..4bc85fa 100644
--- a/webclient/src/components/SceneView.tsx
+++ b/webclient/src/components/SceneView.tsx
@@ -1,5 +1,5 @@
 import { observer } from "mobx-react-lite";
-import type { RuntimeGameObjectInstance, RuntimeScene } from "../types";
+import type { RuntimeScene } from "../types";
 import { GameObjectView } from "./GameObjectView";
 import { ObjectEditorView } from "./ObjectEditorView";
 import { DebugLabelsView } from "./DebugLabelsView";
diff --git a/webclient/src/components/layers/DebugLabelsLayer.tsx b/webclient/src/components/layers/DebugLabelsLayer.tsx
new file mode 100644
index 0000000..091d4c2
--- /dev/null
+++ b/webclient/src/components/layers/DebugLabelsLayer.tsx
@@ -0,0 +1,5 @@
+import { observer } from "mobx-react-lite";
+
+export const DebugLabelsLayer = observer(function () {
+    return null; //TODO
+});
diff --git a/webclient/src/components/layers/GameraLayer.tsx b/webclient/src/components/layers/GameraLayer.tsx
new file mode 100644
index 0000000..7d4e488
--- /dev/null
+++ b/webclient/src/components/layers/GameraLayer.tsx
@@ -0,0 +1,27 @@
+import { useFrame } from "@react-three/fiber";
+import type { Pos3 } from "../../types";
+import { Euler, Quaternion, Vector3 } from "three";
+
+const _q = new Quaternion();
+const _e = new Euler(0, 0, 0, 'YXZ');
+const _offset = new Vector3();
+const _charPos = new Vector3();
+const _lookAt = new Vector3();
+
+type Props = {
+    camera: Pos3;
+};
+
+export function CameraLayer({ camera: cameraPos }: Props) {
+
+    useFrame(({ camera }) => {
+        // const t = rb.translation();
+        // _charPos.set(t.x, t.y, t.z);
+        // _offset.copy(shoulderOffset).applyEuler(_e.set(pitchRef.current, yawRef.current, 0, 'YXZ'));
+        // camera.position.copy(_charPos).add(_offset);
+        // _lookAt.set(t.x, t.y + lookAtY, t.z);
+        camera.lookAt(_lookAt);
+    });
+
+    return null;
+}
diff --git a/webclient/src/components/layers/LayeredThreeView.tsx b/webclient/src/components/layers/LayeredThreeView.tsx
new file mode 100644
index 0000000..d22447d
--- /dev/null
+++ b/webclient/src/components/layers/LayeredThreeView.tsx
@@ -0,0 +1,23 @@
+import { observer } from "mobx-react-lite";
+import { ObjectGeomertiesLayer } from "./ObjectGeomertiesLayer";
+import { Canvas } from "@react-three/fiber";
+import { Perf } from "r3f-perf";
+import { state } from "../../state";
+import { CameraLayer } from "./GameraLayer";
+
+export const LayeredThreeView = observer(function () {
+
+    return <>
+        <Canvas
+        // camera={state.world.character.camera}
+        >
+            <ambientLight intensity={0.5} />
+            <directionalLight position={[5, 5, 5]} intensity={1} />
+
+            <Perf position="bottom-right" />
+
+            <CameraLayer camera={state.worldEditor.camera} />
+            <ObjectGeomertiesLayer />
+        </Canvas>
+    </>;
+});
diff --git a/webclient/src/components/layers/ObjectGeomertiesLayer.tsx b/webclient/src/components/layers/ObjectGeomertiesLayer.tsx
new file mode 100644
index 0000000..52a97dc
--- /dev/null
+++ b/webclient/src/components/layers/ObjectGeomertiesLayer.tsx
@@ -0,0 +1,26 @@
+import { useEffect, useRef } from "react";
+import { useThree, useFrame } from "@react-three/fiber";
+import { ObjectGeometryList } from "../../rendering/ObjectGeometryList";
+import { observer } from "mobx-react-lite";
+import { state } from "../../state";
+
+export const ObjectGeomertiesLayer = observer(function () {
+
+    const geometries = state.view.objectGeometries;
+
+    const threeScene = useThree(s => s.scene);
+    const list = useRef<ObjectGeometryList | null>(null);
+
+    useEffect(() => {
+        const l = new ObjectGeometryList(threeScene, geometries);
+        list.current = l;
+        return () => {
+            l.dispose();
+            list.current = null;
+        };
+    }, [threeScene, geometries]);
+
+    useFrame(() => list.current?.tick());
+
+    return null;
+});
diff --git a/webclient/src/components/voxelEditor/VoxelEditorPage.tsx b/webclient/src/components/voxelEditor/VoxelEditorPage.tsx
index bab5708..906fb92 100644
--- a/webclient/src/components/voxelEditor/VoxelEditorPage.tsx
+++ b/webclient/src/components/voxelEditor/VoxelEditorPage.tsx
@@ -1,11 +1,11 @@
 import { Canvas } from '@react-three/fiber';
-import { useParams, useNavigate, Link } from 'react-router-dom';
+import { useNavigate, Link, useParams } from 'react-router-dom';
 import { observer } from 'mobx-react-lite';
 import { useState, useCallback, useEffect, useRef } from 'react';
-import { state } from '../../state';
 import type { Voxel, V3 } from '../../types';
 import { VoxelEditorScene } from './VoxelEditorScene';
 import { IconArrowLeft, IconArrowBackUp, IconArrowForwardUp, IconPlus, IconTrash } from '@tabler/icons-react';
+import { state } from '../../state';
 
 const PALETTE = [
     '#ffffff', '#cccccc', '#999999', '#555555', '#222222',
@@ -19,7 +19,10 @@ type HistoryEntry =
     | { type: 'remove'; voxel: Voxel };
 
 export const VoxelEditorPage = observer(function () {
+
     const { id } = useParams<{ id: string }>();
+    const objectType = id ? state.view.objectTypeGeometries.get(id) : undefined;
+
     const navigate = useNavigate();
     const [mode, setMode] = useState<'add' | 'remove'>('add');
     const [color, setColor] = useState('#808080');
@@ -28,14 +31,11 @@ export const VoxelEditorPage = observer(function () {
     const history = useRef<HistoryEntry[]>([]);
     const future = useRef<HistoryEntry[]>([]);
 
-    const objectType = id ? state.world.getObjectTypeById(id) : undefined;
-
     useEffect(() => {
         return () => {
-            if (id) 
-state.worldEditor.refreshObjectTypeCaches(id);
+            objectType?.updateRuntimeData();
         };
-    }, [id]);
+    }, [objectType]);
 
     function pushHistory(entry: HistoryEntry) {
         history.current.push(entry);
@@ -46,31 +46,31 @@ state.worldEditor.refreshObjectTypeCaches(id);
 
     const undo = useCallback(() => {
         const entry = history.current.pop();
-        if (!entry || !id)
+        if (!entry)
             return;
         if (entry.type === 'add') {
-            state.worldEditor.removeVoxelFromObjectType(id, entry.voxel.position);
+            objectType?.removeVoxel(entry.voxel.position);
         } else {
-            state.worldEditor.addVoxelToObjectType(id, entry.voxel);
+            objectType?.addVoxel(entry.voxel);
         }
         future.current.push(entry);
         setCanUndo(history.current.length > 0);
         setCanRedo(true);
-    }, [id]);
+    }, [objectType]);
 
     const redo = useCallback(() => {
         const entry = future.current.pop();
-        if (!entry || !id)
+        if (!entry)
             return;
         if (entry.type === 'add') {
-            state.worldEditor.addVoxelToObjectType(id, entry.voxel);
+            objectType?.addVoxel(entry.voxel);
         } else {
-            state.worldEditor.removeVoxelFromObjectType(id, entry.voxel.position);
+            objectType?.removeVoxel(entry.voxel.position);
         }
         history.current.push(entry);
         setCanUndo(true);
         setCanRedo(future.current.length > 0);
-    }, [id]);
+    }, [objectType]);
 
     useEffect(() => {
         function onKeyDown(e: KeyboardEvent) {
@@ -84,24 +84,14 @@ state.worldEditor.refreshObjectTypeCaches(id);
     }, [undo, redo]);
 
     function handleAdd(voxel: Voxel) {
-        if (!id)
-            return;
-        state.worldEditor.addVoxelToObjectType(id, voxel);
-        pushHistory({ type: 'add', voxel });
+        if (objectType?.addVoxel(voxel))
+            pushHistory({ type: 'add', voxel });
     }
 
     function handleRemove(position: V3) {
-        if (!id || !objectType)
-            return;
-        const voxel = objectType.voxels.find(v =>
-            v.position[0] === position[0] &&
-            v.position[1] === position[1] &&
-            v.position[2] === position[2]
-        );
-        if (!voxel)
-            return;
-        state.worldEditor.removeVoxelFromObjectType(id, position);
-        pushHistory({ type: 'remove', voxel });
+        const voxel = objectType?.removeVoxel(position);
+        if (voxel)
+            pushHistory({ type: 'remove', voxel });
     }
 
     if (!objectType) {
@@ -116,11 +106,11 @@ state.worldEditor.refreshObjectTypeCaches(id);
         <div style={{ position: 'fixed', inset: 0, background: '#1a1a2e', display: 'flex', flexDirection: 'column' }}>
             {/* Top bar */}
             <div style={{ display: 'flex', alignItems: 'center', gap: 8, padding: '8px 12px', background: '#11111f', flexShrink: 0 }}>
-                <button onClick={() => navigate(`/editor/objectType/${id}`)} style={btnStyle}>
+                <button onClick={() => navigate(`/editor/objectType/${objectType.objectType.id}`)} style={btnStyle}>
                     <IconArrowLeft size={20} />
                 </button>
-                <span style={{ color: '#ccc', fontWeight: 600 }}>{objectType.name}</span>
-                <span style={{ color: '#666', fontSize: 13 }}>{objectType.voxels.length} voxels</span>
+                <span style={{ color: '#ccc', fontWeight: 600 }}>{objectType.objectType.name}</span>
+                <span style={{ color: '#666', fontSize: 13 }}>{objectType.objectType.voxels.length} voxels</span>
                 <div style={{ flex: 1 }} />
                 <button onClick={undo} disabled={!canUndo} style={{ ...btnStyle, opacity: canUndo ? 1 : 0.35 }}>
                     <IconArrowBackUp size={20} />
@@ -134,7 +124,7 @@ state.worldEditor.refreshObjectTypeCaches(id);
             <div style={{ flex: 1, position: 'relative' }}>
                 <Canvas camera={{ position: [12, 10, 12], fov: 50 }}>
                     <VoxelEditorScene
-                        voxels={objectType.voxels.slice()}
+                        voxels={objectType.objectType.voxels.slice()}
                         mode={mode}
                         color={color}
                         typeId="stone"
diff --git a/webclient/src/components/voxelEditor/VoxelEditorScene.tsx b/webclient/src/components/voxelEditor/VoxelEditorScene.tsx
index 23c6bd4..0021bca 100644
--- a/webclient/src/components/voxelEditor/VoxelEditorScene.tsx
+++ b/webclient/src/components/voxelEditor/VoxelEditorScene.tsx
@@ -3,7 +3,7 @@ import { useState, useMemo, useEffect } from 'react';
 import type { ThreeEvent } from '@react-three/fiber';
 import type { Ray } from 'three';
 import type { Voxel, V3 } from '../../types';
-import { buildVoxelMesh } from '../../utils/graphics/voxelMesh';
+import { buildVoxelGroupMesh } from '../../utils/graphics/voxelMesh';
 
 type Props = {
     voxels: Voxel[];
@@ -64,7 +64,7 @@ interface MergedVoxelMeshProps {
 
 function MergedVoxelMesh({ color, positions, onPointerMove, onClick, onPointerLeave }: MergedVoxelMeshProps) {
     const geo = useMemo(
-        () => buildVoxelMesh(positions),
+        () => buildVoxelGroupMesh(positions),
         [positions],
     );
     useEffect(() => () => { geo.dispose(); }, [geo]);
diff --git a/webclient/src/model/gameFactory.ts b/webclient/src/model/gameFactory.ts
index 9d9b773..2c77087 100644
--- a/webclient/src/model/gameFactory.ts
+++ b/webclient/src/model/gameFactory.ts
@@ -1,5 +1,5 @@
 import { toJS } from "mobx";
-import type { Game, GameScene, RuntimeGameObjectInstance, RuntimeGameScene, RuntimeScene, ScriptAction, ScriptCoroutineContext, World } from "../types";
+import type { Game, Scene, ScriptAction, ScriptCoroutineContext, World } from "../types";
 import { clone } from "../utils";
 import { populateRuntimeScene } from "../utils/runtime";
 import { ScriptGameEventBus } from "../scripts/eventBus";
@@ -24,7 +24,7 @@ export class GameFactory {
         const game = {
             paused: false,
             time: 0,
-            scene: GameFactory.initGameScene(scene),
+            scene,
         };
         return game;
     }
@@ -36,17 +36,13 @@ export class GameFactory {
         }
     }
 
-    public static save(game: Game<GameScene>): void {
+    public static save(game: Game): void {
         localStorage.setItem("game", JSON.stringify(game));
     }
 
-    private static initGameScene(scene: RuntimeScene): RuntimeGameScene {
-        return scene as RuntimeGameScene;
-    }
-
     public static evalGameScripts(
         world: World,
-        scene: RuntimeGameScene,
+        scene: Scene,
         coroutines: ScriptCoroutines,
     ): ScriptGameEventBus {
 
@@ -80,7 +76,7 @@ export class GameFactory {
                     Object.values(scene.objects)
                         .filter((o) => o.typeId == ot.id)
                         .map((liveObj) => {
-                            const snapshot = toJS(liveObj) as RuntimeGameObjectInstance;
+                            const snapshot = toJS(liveObj);
                             snapshot.rb = () => liveObj.rb();
                             return snapshot;
                         })
diff --git a/webclient/src/model/worldFactory.ts b/webclient/src/model/worldFactory.ts
index 2b0df7d..257c301 100644
--- a/webclient/src/model/worldFactory.ts
+++ b/webclient/src/model/worldFactory.ts
@@ -10,6 +10,7 @@ export class WorldFactory {
             voxelTypes: DEFAULT_VOXEL_TYPES,
             initialScene: {
                 objects: {},
+                playerObjectId: undefined,
             },
             gameRules: {
                 gravity: true,
diff --git a/webclient/src/rendering/ObjectGeometryList.ts b/webclient/src/rendering/ObjectGeometryList.ts
new file mode 100644
index 0000000..90f4052
--- /dev/null
+++ b/webclient/src/rendering/ObjectGeometryList.ts
@@ -0,0 +1,76 @@
+import * as THREE from 'three';
+import { MobxReconcilerMap, type ReconcilerMap } from '../utils/reconciler';
+import type { ObjectGeometryViewItem, ObjectTypeGeometryViewItem } from '../state/viewState';
+
+export class ObjectGeometryList {
+    private items: ReconcilerMap<ObjectGeometryViewItem>;
+    private readonly typeRefCounts = new Map<string, number>();
+
+    private readonly matrixObj = new THREE.Object3D();
+    private readonly _p = new THREE.Vector3();
+    private readonly _e = new THREE.Euler();
+    private readonly _q = new THREE.Quaternion();
+
+    constructor(scene: THREE.Scene, geometiries: Iterable<ObjectGeometryViewItem>) {
+        this.items = new MobxReconcilerMap<ObjectGeometryViewItem>({
+            reaction: () => geometiries,
+            keyOf: (item) => item.object.id,
+            initializeItem: (item) => {
+                const typeId = item.objectTypeGeometry.objectType.id;
+                const count = (this.typeRefCounts.get(typeId) ?? 0) + 1;
+                this.typeRefCounts.set(typeId, count);
+                if (count === 1) {
+                    for (const mesh of item.objectTypeGeometry.meshes ?? [])
+                        scene.add(mesh);
+                }
+            },
+            disposeItem: (item) => {
+                const typeId = item.objectTypeGeometry.objectType.id;
+                const count = (this.typeRefCounts.get(typeId) ?? 1) - 1;
+                this.typeRefCounts.set(typeId, count);
+                if (count === 0) {
+                    for (const mesh of item.objectTypeGeometry.meshes ?? [])
+                        scene.remove(mesh);
+                }
+            },
+        });
+    }
+
+    dispose(): void {
+        this.items?.dispose();
+    }
+
+    // Called once per frame — reads MobX observables directly outside any reactive
+    // context, so no subscriptions are created and no re-renders are triggered.
+    tick(): void {
+        const touchedObjectTypes: Record<string, { typeGeometry: ObjectTypeGeometryViewItem, instanceCount: number }> = {};
+
+        this.items.values.forEach((item) => {
+            const obj = item.object;
+
+            this._p.set(obj.position[0], obj.position[1], obj.position[2]);
+            this._e.set(obj.rotation[0], obj.rotation[1], obj.rotation[2]);
+            this._q.setFromEuler(this._e);
+
+            const typeId = item.objectTypeGeometry.objectType.id;
+            if (!touchedObjectTypes[typeId])
+                touchedObjectTypes[typeId] = { typeGeometry: item.objectTypeGeometry, instanceCount: 0 };
+            const instanceIdx = touchedObjectTypes[typeId].instanceCount++;
+
+            for (const mesh of item.objectTypeGeometry.meshes ?? []) {
+                this.matrixObj.position.copy(this._p);
+                this.matrixObj.quaternion.copy(this._q);
+                this.matrixObj.scale.set(obj.scale[0], obj.scale[1], obj.scale[2]);
+                this.matrixObj.updateMatrix();
+                mesh.setMatrixAt(instanceIdx, this.matrixObj.matrix);
+            }
+        });
+
+        for (const objectType of Object.values(touchedObjectTypes)) {
+            for (const mesh of objectType.typeGeometry.meshes ?? []) {
+                mesh.count = objectType.instanceCount;
+                mesh.instanceMatrix.needsUpdate = true;
+            }
+        }
+    }
+}
diff --git a/webclient/src/state/gameState.ts b/webclient/src/state/gameState.ts
index 174f0bc..826038e 100644
--- a/webclient/src/state/gameState.ts
+++ b/webclient/src/state/gameState.ts
@@ -1,6 +1,6 @@
 import { autorun, makeAutoObservable, toJS } from "mobx";
 import type { WorldState } from "./worldState";
-import type { Game, GameObjectInstance, GameScene, Pos3, RuntimeGameScene, ScriptContext, ScriptCoroutineContext } from "../types";
+import type { Game, Pos3, Scene, ScriptContext, ScriptCoroutineContext } from "../types";
 import type { CameraProps } from "@react-three/fiber";
 import type { ScriptGameEventBus } from "../scripts/eventBus";
 import { GameFactory } from "../model/gameFactory";
@@ -13,37 +13,16 @@ export class GameState {
     public debugOverlay: boolean = false;
     public time: number = 0;
     public isFirstTick: boolean;
-    public scene: RuntimeGameScene;
+    public scene: Scene;
 
     private coroutines = new ScriptCoroutines();
     private eventBus: ScriptGameEventBus;
 
-    private sceneObjectsAsSaveables(): GameScene['objects'] {
-        return Object.fromEntries(
-            Object.entries(this.scene.objects).map(([id, obj]) => [id, {
-                id: obj.id,
-                typeId: obj.typeId,
-                physics: obj.physics,
-                gravityScale: obj.gravityScale,
-                position: toJS(obj.position),
-                rotation: toJS(obj.rotation),
-                scale: toJS(obj.scale),
-                version: obj.version,
-                linearVelocity: toJS(obj.linearVelocity),
-                angularVelocity: toJS(obj.angularVelocity),
-                visible: toJS(obj.visible),
-            } satisfies GameObjectInstance])
-        ) as unknown as RuntimeGameScene['objects'];
-    }
-
-    public get asSaveableGame(): Game<GameScene> {
+    public get asGame(): Game {
         return {
             paused: this.isPaused,
             time: this.time,
-            scene: {
-                playerObjectId: this.scene.playerObjectId,
-                objects: this.sceneObjectsAsSaveables(),
-            },
+            scene: this.scene,
         };
     }
 
@@ -126,7 +105,7 @@ export class GameState {
 
     public save(): void {
         console.log('Saving game...');
-        GameFactory.save(this.asSaveableGame);
+        GameFactory.save(this.asGame);
     }
 
     public resume(): void {
diff --git a/webclient/src/state/rootState.ts b/webclient/src/state/rootState.ts
index 5e5d4a2..36ca013 100644
--- a/webclient/src/state/rootState.ts
+++ b/webclient/src/state/rootState.ts
@@ -3,7 +3,7 @@ import { WorldState } from "./worldState";
 import { WorldEditorState } from "./worldEditorState";
 import { GameState } from "./gameState";
 import { MenuState } from "./menuState";
-import type { RuntimeObjectInstance } from "../types";
+import { ViewState } from "./viewState";
 
 export type RenderInfo = {
     calls: number,
@@ -19,6 +19,7 @@ export class RootState {
     public game: GameState | undefined;
     public renderInfo: RenderInfo | undefined;
     public readonly menu = new MenuState();
+    public readonly view = new ViewState(this.world);
 
     constructor() {
         this.worldEditor = new WorldEditorState(this.world);
@@ -52,11 +53,11 @@ export class RootState {
         this.renderInfo = value;
     }
 
-    public markObjectAsPlayer(object: RuntimeObjectInstance) {
+    public markObjectAsPlayer(objectId: string) {
         if (this.game)
-            this.game.scene.playerObjectId = object.id;
+            this.game.scene.playerObjectId = objectId;
         else
-            this.world.data.initialScene.playerObjectId = object.id;
+            this.world.data.initialScene.playerObjectId = objectId;
     }
 }
 
diff --git a/webclient/src/state/viewState.ts b/webclient/src/state/viewState.ts
new file mode 100644
index 0000000..4b886cd
--- /dev/null
+++ b/webclient/src/state/viewState.ts
@@ -0,0 +1,135 @@
+import * as THREE from 'three';
+import { action, makeAutoObservable, makeObservable, observable, reaction, type IReactionDisposer } from "mobx";
+import type { ObjectInstance, ObjectInstanceRigidBody, ObjectType, Scene, V3, Voxel, VoxelGroup } from "../types";
+import { state } from "./rootState";
+import { getObjectVoxelGroups } from "../utils/graphics/voxelGroup";
+import { buildVoxelGroupMesh } from "../utils/graphics/voxelMesh";
+import { buildObjectTrimesh } from '../utils/graphics/mesh';
+import { computeBoundingBox } from '../utils/runtime';
+import { MobxReconcilerMap } from '../utils/reconciler';
+
+export abstract class ViewItem {
+}
+
+export class ObjectTypeGeometryViewItem extends ViewItem {
+    public readonly objectType: ObjectType;
+
+    public voxelGroups: VoxelGroup[] | undefined;
+    public colliderMesh: [Float32Array, Uint32Array] | undefined;
+    public boundingBox: { min: V3; max: V3 } | undefined;
+    public meshes: THREE.InstancedMesh[] | undefined;
+
+    private readonly _disposeVoxelReaction: IReactionDisposer;
+
+    constructor(objectType: ObjectType) {
+        super();
+        this.objectType = objectType;
+        makeObservable(this, {
+            voxelGroups: observable.ref,
+            colliderMesh: observable.ref,
+            boundingBox: observable.ref,
+            meshes: observable.ref,
+            updateRuntimeData: action,
+        });
+        this._disposeVoxelReaction = reaction(
+            () => objectType.voxels.map(v => `${v.position}-${v.typeId}`).join('|'),
+            () => this.updateRuntimeData(),
+        );
+        this.updateRuntimeData();
+    }
+
+    public dispose(): void {
+        this._disposeVoxelReaction();
+    }
+
+    public addVoxel(voxel: Voxel): boolean {
+        const occupied = this.objectType.voxels.some(v =>
+            v.position[0] === voxel.position[0] &&
+            v.position[1] === voxel.position[1] &&
+            v.position[2] === voxel.position[2]
+        );
+        if (!occupied) {
+            this.objectType.voxels.push(voxel);
+            return true;
+        }
+        return false;
+    }
+
+    public removeVoxel(position: V3): Voxel | undefined {
+        const idx = this.objectType.voxels.findIndex(v =>
+            v.position[0] === position[0] &&
+            v.position[1] === position[1] &&
+            v.position[2] === position[2]
+        );
+        if (idx !== -1)
+            return this.objectType.voxels.splice(idx, 1)[0];
+    }
+
+    public updateRuntimeData(): void {
+        this.voxelGroups = getObjectVoxelGroups(this.objectType, state.world.data.voxelTypes);
+        this.meshes = [];
+        for (const vg of this.voxelGroups) {
+            const geo = buildVoxelGroupMesh(vg.positions);
+            const mat = new THREE.MeshStandardMaterial({
+                color: vg.color,
+                opacity: vg.opacity,
+                transparent: vg.opacity < 1,
+            });
+            const mesh = new THREE.InstancedMesh(geo, mat, 1000);
+            this.meshes.push(mesh);
+        }
+        this.colliderMesh = buildObjectTrimesh(this.objectType, state.world.data.voxelTypes);
+        this.boundingBox = computeBoundingBox(this.objectType);
+    }
+}
+
+export class ObjectGeometryViewItem extends ViewItem {
+    public readonly object: ObjectInstance;
+    public readonly objectTypeGeometry: ObjectTypeGeometryViewItem;
+
+    public rb: (() => ObjectInstanceRigidBody | null) | undefined;
+
+    constructor(object: ObjectInstance, objectTypeGeometry: ObjectTypeGeometryViewItem) {
+        super();
+        this.object = object;
+        this.objectTypeGeometry = objectTypeGeometry;
+    }
+}
+
+export class ViewState {
+    public objectTypeGeometries: MobxReconcilerMap<ObjectType, ObjectTypeGeometryViewItem>;
+    public objectGeometries: MobxReconcilerMap<ObjectInstance, ObjectGeometryViewItem>;
+
+    constructor(world: { data: { objectTypes: Record<string, ObjectType>; initialScene: Scene } }) {
+        makeAutoObservable(
+            this,
+        );
+        this.objectTypeGeometries = new MobxReconcilerMap<ObjectType, ObjectTypeGeometryViewItem>({
+            reaction: () => Object.values(world.data.objectTypes),
+            keyOf: (ot) => ot.id,
+            mapItem: (ot) => new ObjectTypeGeometryViewItem(ot),
+            updateItem: () => true,
+            disposeItem: (item) => { item.dispose(); },
+        });
+
+        this.objectGeometries = new MobxReconcilerMap<ObjectInstance, ObjectGeometryViewItem>({
+            reaction: () => Object.values(world.data.initialScene.objects)
+                .filter(obj => obj.visible)
+                .filter(obj => !!world.data.objectTypes[obj.typeId]),
+            keyOf: (obj) => obj.id,
+            mapItem: (obj) => new ObjectGeometryViewItem(obj, this.objectTypeGeometries.get(obj.typeId)!),
+        });
+    }
+
+    public dispose(): void {
+        this.objectTypeGeometries.dispose();
+        this.objectGeometries.dispose();
+    }
+
+    public get items(): ViewItem[] {
+        return [
+            ...this.objectTypeGeometries,
+            ...this.objectGeometries,
+        ];
+    }
+}
diff --git a/webclient/src/state/worldEditorState.ts b/webclient/src/state/worldEditorState.ts
index ed671e9..c64fae5 100644
--- a/webclient/src/state/worldEditorState.ts
+++ b/webclient/src/state/worldEditorState.ts
@@ -1,13 +1,11 @@
 import { makeAutoObservable, runInAction } from "mobx";
 import type { WorldState } from "./worldState";
-import { type ObjectInstance, type Pos3, type R3, type V3, type RuntimeScene, type ObjectType, type Voxel } from "../types";
+import { type ObjectInstance, type Pos3, type R3, type V3, type ObjectType, type Scene } from "../types";
 import { createObjectInstance } from "../utils/object";
 import { randomId } from "../utils";
 import { state } from "./rootState";
-import { populateRuntimeObject, computeBoundingBox } from "../utils/runtime";
+import { populateRuntimeObject } from "../utils/runtime";
 import { DEFAULT_VOXEL_TYPE } from "../model/defaultVoxelTypes";
-import { getObjectVoxelGroups } from "../utils/graphics/voxelGroup";
-import { buildObjectTrimesh } from "../utils/graphics/mesh";
 
 export const ObjectEditModeEnum = [
     'translate',
@@ -99,7 +97,7 @@ export class WorldEditorState {
         this.setSelection(undefined);
     }
 
-    public get scene(): RuntimeScene {
+    public get scene(): Scene {
         return this.world.data.initialScene;
     }
 
@@ -168,48 +166,6 @@ export class WorldEditorState {
         return objectType;
     }
 
-    public addVoxelToObjectType(typeId: string, voxel: Voxel): void {
-        const objectType = this.world.getObjectTypeById(typeId);
-        if (!objectType)
-            return;
-        const occupied = objectType.voxels.some(v =>
-            v.position[0] === voxel.position[0] &&
-            v.position[1] === voxel.position[1] &&
-            v.position[2] === voxel.position[2]
-        );
-        if (!occupied)
-            objectType.voxels.push(voxel);
-    }
-
-    public removeVoxelFromObjectType(typeId: string, position: V3): void {
-        const objectType = this.world.getObjectTypeById(typeId);
-        if (!objectType)
-            return;
-        const idx = objectType.voxels.findIndex(v =>
-            v.position[0] === position[0] &&
-            v.position[1] === position[1] &&
-            v.position[2] === position[2]
-        );
-        if (idx !== -1)
-            objectType.voxels.splice(idx, 1);
-    }
-
-    public refreshObjectTypeCaches(typeId: string): void {
-        const objectType = this.world.getObjectTypeById(typeId);
-        if (!objectType)
-            return;
-        const world = this.world.data;
-        const now = Date.now();
-        for (const obj of Object.values(this.scene.objects)) {
-            if (obj.typeId !== typeId)
-                continue;
-            obj.cache.voxelGroups = getObjectVoxelGroups(objectType, world.voxelTypes);
-            obj.cache.colliderMesh = buildObjectTrimesh(objectType, world.voxelTypes);
-            obj.cache.boundingBox = computeBoundingBox(objectType);
-            obj.cache.updatedAt = now;
-        }
-    }
-
     public deleteObjectType(typeId: string) {
         if (this.selection?.type === 'objectType' && this.selection.id === typeId)
             this.resetSelection();
diff --git a/webclient/src/state/worldState.ts b/webclient/src/state/worldState.ts
index ee8a679..ad9bb4e 100644
--- a/webclient/src/state/worldState.ts
+++ b/webclient/src/state/worldState.ts
@@ -12,30 +12,11 @@ export class WorldState {
 
     private _buildSave(): World {
         const d = this.data;
-        return {
-            objectTypes: toJS(d.objectTypes),
-            voxelTypes: toJS(d.voxelTypes),
-            editorCamera: toJS(d.editorCamera),
-            gameRules: toJS(d.gameRules),
-            initialScene: {
-                playerObjectId: d.initialScene.playerObjectId,
-                objects: Object.fromEntries(
-                    Object.entries(d.initialScene.objects).map(([id, obj]) => [id, {
-                        id: obj.id,
-                        typeId: obj.typeId,
-                        physics: obj.physics,
-                        gravityScale: obj.gravityScale,
-                        position: toJS(obj.position),
-                        rotation: toJS(obj.rotation),
-                        scale: toJS(obj.scale),
-                    } satisfies ObjectInstance])
-                ),
-            },
-        };
+        return toJS(d);
     }
 
     private startAutoSave() {
-        return autorun(() => WorldFactory.save(this._buildSave()), { delay: 500 });
+        return autorun(() => this.save(), { delay: 500 });
     }
 
     private withoutAutoSave(fn: () => void) {
@@ -105,6 +86,9 @@ export class WorldState {
                         position: [0, -1, 0],
                         rotation: [0, 0, 0],
                         scale: [1, 1, 1],
+                        visible: true,
+                        linearVelocity: [0, 0, 0],
+                        angularVelocity: [0, 0, 0],
                     },
                     ...objectMap,
                 },
@@ -128,6 +112,7 @@ export class WorldState {
     }
 
     public save(): void {
+        console.log('Saving world...');
         WorldFactory.save(this._buildSave());
     }
 
diff --git a/webclient/src/types/model/game.ts b/webclient/src/types/model/game.ts
index ca337ab..5877dee 100644
--- a/webclient/src/types/model/game.ts
+++ b/webclient/src/types/model/game.ts
@@ -1,7 +1,7 @@
-import type { GameScene, RuntimeGameScene } from "./scene";
+import type { Scene } from "./scene";
 
-export type Game<TScene extends GameScene = RuntimeGameScene> = {
+export type Game = {
     paused: boolean;
     time: number;
-    scene: TScene;
+    scene: Scene;
 }
diff --git a/webclient/src/types/model/object.ts b/webclient/src/types/model/object.ts
index f05cd07..28e3a06 100644
--- a/webclient/src/types/model/object.ts
+++ b/webclient/src/types/model/object.ts
@@ -1,5 +1,4 @@
 import type { R3, V3 } from "../3d";
-import type { Runtime } from "./runtime";
 import type { Voxel } from "./voxel";
 
 export type ObjectType = {
@@ -8,7 +7,7 @@ export type ObjectType = {
     voxels: Voxel[];
     program?: string;
     javascript?: string;
-}
+};
 
 export type ObjectInstance = {
     id: string;
@@ -19,15 +18,7 @@ export type ObjectInstance = {
     rotation: R3;
     scale: V3;
     visible: boolean;
-}
 
-export type GameObjectData = {
-    version: number; // increment to force three and physics changes
     linearVelocity: V3;
-    angularVelocity: R3;
-}
-
-export type GameObjectInstance = ObjectInstance & GameObjectData;
-
-export type RuntimeObjectInstance = Runtime<ObjectInstance>;
-export type RuntimeGameObjectInstance = Runtime<GameObjectInstance>;
+    angularVelocity: V3;
+};
diff --git a/webclient/src/types/model/runtime.ts b/webclient/src/types/model/runtime.ts
index cce95ef..5f75786 100644
--- a/webclient/src/types/model/runtime.ts
+++ b/webclient/src/types/model/runtime.ts
@@ -1,6 +1,5 @@
 import type { V3 } from "../3d";
 import type { VoxelGroup } from "../runtime";
-import type { ObjectInstance } from "./object";
 
 export type ObjectInstanceRigidBody = {
     handle: number; // rapier RigidBodyHandle
@@ -13,13 +12,12 @@ export type ObjectInstanceRigidBody = {
 };
 
 export type ObjectInstanceRuntimeData = {
-    cache: {
-        voxelGroups: VoxelGroup[];
-        colliderMesh: [Float32Array, Uint32Array] | null;
-        boundingBox: { min: V3; max: V3 };
-        updatedAt: number;
-    };
     rb: () => ObjectInstanceRigidBody | null;
-}
+};
 
-export type Runtime<T extends ObjectInstance> = T & ObjectInstanceRuntimeData;
+export type ObjectTypeRuntimeData = {
+    voxelGroups: VoxelGroup[];
+    colliderMesh: [Float32Array, Uint32Array] | null;
+    boundingBox: { min: V3; max: V3 };
+    updatedAt: number;
+}
diff --git a/webclient/src/types/model/scene.ts b/webclient/src/types/model/scene.ts
index 4314e82..dd7fcf3 100644
--- a/webclient/src/types/model/scene.ts
+++ b/webclient/src/types/model/scene.ts
@@ -1,10 +1,6 @@
-import type { GameObjectInstance, ObjectInstance, RuntimeGameObjectInstance, RuntimeObjectInstance } from "./object";
+import type { ObjectInstance } from "./object";
 
-export type Scene<TObject extends ObjectInstance> = {
-    objects: Record<string, TObject>;
+export type Scene = {
+    objects: Record<string, ObjectInstance>;
     playerObjectId: string | undefined;
 }
-
-export type GameScene = Scene<GameObjectInstance>;
-export type RuntimeScene = Scene<RuntimeObjectInstance>;
-export type RuntimeGameScene = Scene<RuntimeGameObjectInstance>;
diff --git a/webclient/src/utils/graphics/mesh.ts b/webclient/src/utils/graphics/mesh.ts
index f868343..a1d4614 100644
--- a/webclient/src/utils/graphics/mesh.ts
+++ b/webclient/src/utils/graphics/mesh.ts
@@ -1,10 +1,10 @@
 import type { ObjectType, VoxelType } from "../../types";
 
-export function buildObjectTrimesh(objectType: ObjectType, voxelTypes: Record<string, VoxelType>): [Float32Array, Uint32Array] | null {
+export function buildObjectTrimesh(objectType: ObjectType, voxelTypes: Record<string, VoxelType>): [Float32Array, Uint32Array] | undefined {
     const collidable = objectType.voxels.filter((v) => voxelTypes[v.typeId]?.collidable !== false);
 
     if (!collidable.length)
-        return null;
+        return;
 
     const n = collidable.length;
     const verts = new Float32Array(n * 8 * 3);
diff --git a/webclient/src/utils/graphics/voxelMesh.ts b/webclient/src/utils/graphics/voxelMesh.ts
index 635de77..bb25e70 100644
--- a/webclient/src/utils/graphics/voxelMesh.ts
+++ b/webclient/src/utils/graphics/voxelMesh.ts
@@ -28,7 +28,7 @@ function triangulatePolygon(polygon: PolygonClipping.Polygon): V2[] {
     return result;
 }
 
-export function buildVoxelMesh(voxels: V3[]): BufferGeometry {
+export function buildVoxelGroupMesh(voxels: V3[]): BufferGeometry {
 
     const vertices: V3[] = [];
     const normals: V3[] = [];
diff --git a/webclient/src/utils/object.ts b/webclient/src/utils/object.ts
index 46cbae0..661e7e9 100644
--- a/webclient/src/utils/object.ts
+++ b/webclient/src/utils/object.ts
@@ -6,6 +6,7 @@ export function createObjectInstance(id: string, typeId: string): ObjectInstance
         typeId: typeId,
         physics: true,
         gravityScale: 1,
+        visible: true,
         position: [0, 0, 0],
         rotation: [0, 0, 0],
         scale: [1, 1, 1],
diff --git a/webclient/src/utils/reconciler.ts b/webclient/src/utils/reconciler.ts
new file mode 100644
index 0000000..a344f20
--- /dev/null
+++ b/webclient/src/utils/reconciler.ts
@@ -0,0 +1,113 @@
+import { observable, runInAction, reaction, type IReactionDisposer } from "mobx";
+
+type MapItemOption<TInput, TStored> =
+    TStored extends TInput ? TInput extends TStored
+    ? { mapItem?: never }
+    : { mapItem(value: TInput): TStored }
+    : { mapItem(value: TInput): TStored };
+
+export type ReconcilerMapOptions<TInput, TStored, TKey extends string> =
+    {
+        keyOf(item: TInput): TKey;
+        initializeItem?(item: TStored, source: TInput): void;
+        updateItem?(current: TStored, next: TStored, nextSource: TInput): void;
+        disposeItem?(item: TStored): void;
+    } & MapItemOption<TInput, TStored>;
+
+export class ReconcilerMap<TInput, TStored = TInput, TKey extends string = string> {
+    private readonly options: ReconcilerMapOptions<TInput, TStored, TKey>;
+    private readonly items = observable.map<TKey, { input: TInput; stored: TStored }>();
+
+    constructor(
+        options: ReconcilerMapOptions<TInput, TStored, TKey>,
+    ) {
+        this.options = options;
+    }
+
+    public get values(): readonly TStored[] {
+        return [...this.items.values()].map(e => e.stored);
+    }
+
+    public get length(): number {
+        return this.items.size;
+    }
+
+    public has(key: TKey): boolean {
+        return this.items.has(key);
+    }
+
+    public get(key: TKey): TStored | undefined {
+        return this.items.get(key)?.stored;
+    }
+
+    public *[Symbol.iterator](): Iterator<TStored> {
+        for (const { stored } of this.items.values())
+            yield stored;
+    }
+
+    public reconcile(nextItems: Iterable<TInput>): void {
+        const nextMap = new Map<TKey, TInput>();
+
+        for (const item of nextItems) {
+            nextMap.set(this.options.keyOf(item), item);
+        }
+
+        // Remove disappeared items
+        for (const [key, { stored }] of this.items) {
+            if (!nextMap.has(key)) {
+                runInAction(() => this.items.delete(key));
+                this.options.disposeItem?.(stored);
+            }
+        }
+
+        // Add or update existing items
+        for (const [key, next] of nextMap) {
+            const existing = this.items.get(key);
+
+            if (existing === undefined) {
+                // New key — always call mapItem (or identity when TStored = TInput)
+                const nextMapped = (this.options.mapItem?.(next) ?? next) as TStored;
+                runInAction(() => this.items.set(key, { input: next, stored: nextMapped }));
+                this.options.initializeItem?.(nextMapped, next);
+            } else if (existing.input !== next) {
+                // Same key, different input reference — call mapItem and update
+                const nextMapped = (this.options.mapItem?.(next) ?? next) as TStored;
+                runInAction(() => this.items.set(key, { input: next, stored: nextMapped }));
+                if (this.options.updateItem?.(existing.stored, nextMapped, next))
+                    this.options.disposeItem?.(existing.stored);
+            }
+            // Same key, same input reference — skip mapItem entirely
+        }
+    }
+
+    public dispose(): void {
+        const stored = [...this];
+        runInAction(() => this.items.clear());
+        for (const item of stored)
+            this.options.disposeItem?.(item);
+    }
+}
+
+export type MobxReconcilerMapOptions<TInput, TStored, TKey extends string> =
+    ReconcilerMapOptions<TInput, TStored, TKey> & { reaction(): Iterable<TInput> };
+
+export class MobxReconcilerMap<TInput, TStored = TInput, TKey extends string = string> extends ReconcilerMap<TInput, TStored, TKey> {
+    private readonly disposeReaction: IReactionDisposer;
+
+    constructor(options: MobxReconcilerMapOptions<TInput, TStored, TKey>) {
+        super(options);
+
+        // reaction data fn (tracked) fires only on object list structural changes.
+        // effect fn (untracked) feeds current instances to the reconciler.
+        this.disposeReaction = reaction<TInput[], true>(
+            () => Array.from(options.reaction()),
+            () => { this.reconcile(options.reaction()); },
+            { fireImmediately: true },
+        );
+    }
+
+    public dispose(): void {
+        this.disposeReaction();
+        super.dispose();
+    }
+}
diff --git a/webclient/src/utils/runtime/object.ts b/webclient/src/utils/runtime/object.ts
index 5862900..44491a3 100644
--- a/webclient/src/utils/runtime/object.ts
+++ b/webclient/src/utils/runtime/object.ts
@@ -1,5 +1,5 @@
 import { getObjectVoxelGroups } from "../graphics/voxelGroup";
-import type { GameObjectInstance, ObjectInstance, ObjectType, RuntimeObjectInstance, V3, World } from "../../types";
+import type { ObjectInstance, ObjectType, RuntimeObjectInstance, RuntimeObjectType, V3, World } from "../../types";
 import { buildObjectTrimesh } from "../graphics/mesh";
 
 export function computeBoundingBox(objectType: ObjectType): { min: V3; max: V3 } {
@@ -18,27 +18,34 @@ export function computeBoundingBox(objectType: ObjectType): { min: V3; max: V3 }
     return { min: [minX, minY, minZ], max: [maxX, maxY, maxZ] };
 }
 
-export function populateRuntimeObject(object: ObjectInstance, world: World): RuntimeObjectInstance {
-    const objectType = world.objectTypes[object.typeId];
-
+export function populateRuntimeObjectType(value: ObjectType, world: World): RuntimeObjectType {
     return {
-        ...object,
-        cache: {
-            voxelGroups: getObjectVoxelGroups(objectType, world.voxelTypes),
-            colliderMesh: buildObjectTrimesh(objectType, world.voxelTypes),
-            boundingBox: computeBoundingBox(objectType),
+        ...value,
+        runtime: {
+            voxelGroups: getObjectVoxelGroups(value, world.voxelTypes),
+            colliderMesh: buildObjectTrimesh(value, world.voxelTypes),
+            boundingBox: computeBoundingBox(value),
             updatedAt: 0,
         },
-        rb: () => null,
     };
 }
 
-export function depopulateRuntimeObject(object: RuntimeObjectInstance, _world: World): ObjectInstance {
-    const { cache: _cache, rb: _rb, ...result } = object;
+export function populateRuntimeObject(value: ObjectInstance, _world: World): RuntimeObjectInstance {
+    return {
+        ...value,
+        runtime: {
+            rb: () => null,
+        },
+    };
+}
+
+export function depopulateRuntimeObjectType(value: RuntimeObjectType, _world: World): ObjectType {
+    const { runtime: _, ...result } = value;
     return result;
 }
 
 
-export function isGameObject(obj: ObjectInstance): obj is GameObjectInstance {
-    return 'version' in obj;
+export function depopulateRuntimeObject(value: RuntimeObjectInstance, _world: World): ObjectInstance {
+    const { runtime: _, ...result } = value;
+    return result;
 }