diff --git a/packages/frontend/src/pages/room.add-object-dialog.vue b/packages/frontend/src/pages/room.add-object-dialog.vue
index b163c4ac20..67612cdc82 100644
--- a/packages/frontend/src/pages/room.add-object-dialog.vue
+++ b/packages/frontend/src/pages/room.add-object-dialog.vue
@@ -31,23 +31,35 @@ SPDX-License-Identifier: AGPL-3.0-only
 		</div>
 		<div v-show="selectedId != null" :class="$style.preview" class="_panel">
 			<canvas ref="canvas" :class="$style.canvas"></canvas>
-			<button :class="$style.unselectButton" @click="selectedId = null">x</button>
+			<MkButton :class="$style.unselectButton" small iconOnly @click="selectedId = null"><i class="ti ti-x"></i></MkButton>
+			<MkButton :class="$style.customizeButton" small iconOnly @click=""><i class="ti ti-settings"></i></MkButton>
+			<div v-if="selectedObjectDef != null && selectedInstanceId != null" :class="$style.customize">
+				<XObjectCustomizeForm :schema="selectedObjectDef.options.schema" :options="selectedObjectOptionsState" @update="(k, v) => { engine.updateObjectOption(k, v); triggerRef(selectedObjectOptionsState) }"></XObjectCustomizeForm>
+			</div>
 		</div>
 	</div>
 </MkModalWindow>
 </template>
 
 <script setup lang="ts">
-import { ref, useTemplateRef, watch, onMounted, onUnmounted, reactive, nextTick, shallowRef } from 'vue';
+import { ref, useTemplateRef, watch, onMounted, onUnmounted, reactive, nextTick, shallowRef, computed, triggerRef } from 'vue';
+import XObjectCustomizeForm from './room.object-customize-form.vue';
+import type { RoomObjectInstance, RoomStateObject } from '@/world/room/object.js';
 import { i18n } from '@/i18n.js';
 import MkModalWindow from '@/components/MkModalWindow.vue';
 import * as os from '@/os.js';
 import { OBJECT_DEFS } from '@/world/room/object-defs.js';
 import { createRoomObjectPreviewEngine, RoomObjectPreviewEngine } from '@/world/room/previewEngine.js';
 import { camelToKebab } from '@/world/utility.js';
+import MkButton from '@/components/MkButton.vue';
+
+// TODO: instanceのidと紛らわしいのでid -> typeにする
 
 const emit = defineEmits<{
-	(ev: 'ok', id: string): void;
+	(ev: 'ok', ctx: {
+		id: string;
+		options: any;
+	}): void;
 	(ev: 'cancel'): void;
 	(ev: 'closed'): void;
 }>();
@@ -55,6 +67,9 @@ const emit = defineEmits<{
 const dialog = useTemplateRef('dialog');
 const canvas = useTemplateRef('canvas');
 const selectedId = ref<string | null>(null);
+const selectedInstanceId = ref<string | null>(null);
+const selectedObjectOptionsState = shallowRef<RoomStateObject | null>(null);
+const selectedObjectDef = computed(() => OBJECT_DEFS.find(def => def.id === selectedId.value) ?? null);
 const engine = shallowRef<RoomObjectPreviewEngine | null>(null);
 
 onMounted(async () => {
@@ -70,17 +85,27 @@ onUnmounted(() => {
 });
 
 watch(selectedId, (newId) => {
-	if (newId == null) return;
-
-	nextTick(() => {
-		engine.value!.load(newId);
-		engine.value!.resize();
-	});
+	if (newId == null) {
+		engine.value!.clear();
+		selectedInstanceId.value = null;
+		selectedObjectOptionsState.value = null;
+	} else {
+		nextTick(() => {
+			engine.value!.load(newId).then(res => {
+				selectedInstanceId.value = res.id;
+				selectedObjectOptionsState.value = res.options;
+				engine.value!.resize();
+			});
+		});
+	}
 });
 
 function ok() {
 	if (selectedId.value == null) return;
-	emit('ok', selectedId.value);
+	emit('ok', {
+		id: selectedId.value,
+		options: selectedObjectOptionsState.value,
+	});
 	dialog.value?.close();
 }
 
@@ -146,8 +171,20 @@ async function cancel() {
 }
 
 .unselectButton {
+	position: absolute;
+	top: 8px;
+	left: 8px;
+}
+
+.customizeButton {
 	position: absolute;
 	top: 8px;
 	right: 8px;
 }
+
+.customize {
+	position: absolute;
+	top: 8px;
+	left: 8px;
+}
 </style>
diff --git a/packages/frontend/src/pages/room.object-customize-form.vue b/packages/frontend/src/pages/room.object-customize-form.vue
new file mode 100644
index 0000000000..86f935fd11
--- /dev/null
+++ b/packages/frontend/src/pages/room.object-customize-form.vue
@@ -0,0 +1,59 @@
+<!--
+SPDX-FileCopyrightText: syuilo and misskey-project
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<div :class="$style.root">
+	<div class="_gaps">
+		<div v-for="[k, s] in Object.entries(schema)" :key="k">
+			<div>{{ s.label }}</div>
+			<div v-if="s.type === 'color'">
+				<MkInput :modelValue="getHex(options[k])" type="color" @update:modelValue="v => { const c = getRgb(v); if (c != null) emit('update', k, c); }"></MkInput>
+			</div>
+			<div v-else-if="s.type === 'boolean'">
+				<MkSwitch :modelValue="options[k]" @update:modelValue="v => emit('update', k, v)"></MkSwitch>
+			</div>
+			<div v-else-if="s.type === 'enum'">
+				<MkSelect :items="s.enum.map(e => ({ label: e, value: e }))" :modelValue="options[k]" @update:modelValue="v => emit('update', k, v)"></MkSelect>
+			</div>
+			<div v-else-if="s.type === 'range'">
+				<MkRange :continuousUpdate="true" :min="s.min" :max="s.max" :step="s.step" :modelValue="options[k]" @update:modelValue="v => emit('update', k, v)"></MkRange>
+			</div>
+			<div v-else-if="s.type === 'image'">
+				<MkInput type="text" :modelValue="options[k]" @update:modelValue="v => emit('update', k, v)"></MkInput>
+			</div>
+			<div v-else-if="s.type === 'seed'">
+				<MkRange :continuousUpdate="true" :min="0" :max="1000" :step="1" :modelValue="options[k]" @update:modelValue="v => emit('update', k, v)"></MkRange>
+			</div>
+		</div>
+	</div>
+</div>
+</template>
+
+<script lang="ts" setup>
+import { computed, defineAsyncComponent, nextTick, onMounted, onUnmounted, ref, shallowRef, useTemplateRef, watch } from 'vue';
+import type { ObjectDef } from '@/world/room/object.js';
+import { i18n } from '@/i18n.js';
+import MkButton from '@/components/MkButton.vue';
+import MkSelect from '@/components/MkSelect.vue';
+import * as os from '@/os.js';
+import MkInput from '@/components/MkInput.vue';
+import MkSwitch from '@/components/MkSwitch.vue';
+import MkRange from '@/components/MkRange.vue';
+import { getHex, getRgb } from '@/world/utility.js';
+
+const props = defineProps<{
+	schema: ObjectDef['options']['schema'];
+	options: any;
+}>();
+
+const emit = defineEmits<{
+	(ev: 'update', k: string, v: any): void;
+}>();
+</script>
+
+<style lang="scss" module>
+.root {
+}
+</style>
diff --git a/packages/frontend/src/pages/room.vue b/packages/frontend/src/pages/room.vue
index 99799cc312..036ca99464 100644
--- a/packages/frontend/src/pages/room.vue
+++ b/packages/frontend/src/pages/room.vue
@@ -44,26 +44,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<div v-if="controller.isReady.value && controller.isEditMode.value && controller.selected.value != null && !controller.grabbing.value" :key="controller.selected.value.objectId" class="_panel" :class="$style.overlayObjectInfoPanel">
 				{{ controller.selected.value.objectDef.name }}
 
-				<div class="_gaps">
-					<div v-for="[k, s] in Object.entries(controller.selected.value.objectDef.options.schema)" :key="k">
-						<div>{{ s.label }}</div>
-						<div v-if="s.type === 'color'">
-							<MkInput :modelValue="getHex(controller.selected.value.objectState.options[k])" type="color" @update:modelValue="v => { const c = getRgb(v); if (c != null) controller.updateObjectOption(controller.selected.value.objectId, k, c); }"></MkInput>
-						</div>
-						<div v-else-if="s.type === 'boolean'">
-							<MkSwitch :modelValue="controller.selected.value.objectState.options[k]" @update:modelValue="v => controller.updateObjectOption(controller.selected.value.objectId, k, v)"></MkSwitch>
-						</div>
-						<div v-else-if="s.type === 'enum'">
-							<MkSelect :items="s.enum.map(e => ({ label: e, value: e }))" :modelValue="controller.selected.value.objectState.options[k]" @update:modelValue="v => controller.updateObjectOption(controller.selected.value.objectId, k, v)"></MkSelect>
-						</div>
-						<div v-else-if="s.type === 'range'">
-							<MkRange :continuousUpdate="true" :min="s.min" :max="s.max" :step="s.step" :modelValue="controller.selected.value.objectState.options[k]" @update:modelValue="v => controller.updateObjectOption(controller.selected.value.objectId, k, v)"></MkRange>
-						</div>
-						<div v-else-if="s.type === 'image'">
-							<MkInput type="text" :modelValue="controller.selected.value.objectState.options[k]" @update:modelValue="v => controller.updateObjectOption(controller.selected.value.objectId, k, v)"></MkInput>
-						</div>
-					</div>
-				</div>
+				<XObjectCustomizeForm :schema="controller.selected.value.objectDef.options.schema" :options="controller.selected.value.objectState.options" @update="(k, v) => controller.updateObjectOption(controller.selected.value.objectId, k, v)"></XObjectCustomizeForm>
 			</div>
 
 			<div v-if="isRoomSettingsOpen" class="_panel" :class="$style.overlayObjectInfoPanel">
@@ -119,6 +100,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <script lang="ts" setup>
 import { computed, defineAsyncComponent, nextTick, onMounted, onUnmounted, ref, shallowRef, useTemplateRef, watch } from 'vue';
+import XObjectCustomizeForm from './room.object-customize-form.vue';
 import { definePage } from '@/page.js';
 import { i18n } from '@/i18n.js';
 import { ensureSignin } from '@/i';
@@ -129,7 +111,7 @@ import MkInput from '@/components/MkInput.vue';
 import MkSwitch from '@/components/MkSwitch.vue';
 import MkRange from '@/components/MkRange.vue';
 import { RoomController } from '@/world/room/controller.js';
-import { cm } from '@/world/utility.js';
+import { cm, getHex, getRgb } from '@/world/utility.js';
 import { deepClone } from '@/utility/clone.js';
 
 const canvas = useTemplateRef('canvas');
@@ -283,7 +265,7 @@ async function addObject(ev: PointerEvent) {
 	const { dispose } = await os.popupAsyncWithDialog(import('./room.add-object-dialog.vue').then(x => x.default), {
 	}, {
 		ok: async (res) => {
-			controller.addObject(res);
+			controller.addObject(res.id, res.options);
 			canvas.value!.focus();
 		},
 		closed: () => {
@@ -306,24 +288,6 @@ function exitEditMode() {
 	controller.exitEditMode();
 }
 
-function getHex(c: [number, number, number]) {
-	return `#${c.map(x => Math.round(x * 255).toString(16).padStart(2, '0')).join('')}`;
-}
-
-function getRgb(hex: string | number): [number, number, number] | null {
-	if (
-		typeof hex === 'number' ||
-		typeof hex !== 'string' ||
-		!/^#([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/.test(hex)
-	) {
-		return null;
-	}
-
-	const m = hex.slice(1).match(/[0-9a-fA-F]{2}/g);
-	if (m == null) return [0, 0, 0];
-	return m.map(x => parseInt(x, 16) / 255) as [number, number, number];
-}
-
 function save() {
 	latestData = deepClone(controller.roomState.value);
 	localStorage.setItem('roomData', JSON.stringify(latestData));
diff --git a/packages/frontend/src/world/room/controller.ts b/packages/frontend/src/world/room/controller.ts
index 8cecbe3e00..8606b20b25 100644
--- a/packages/frontend/src/world/room/controller.ts
+++ b/packages/frontend/src/world/room/controller.ts
@@ -255,11 +255,11 @@ export class RoomController {
 		}
 	}
 
-	public addObject(type: string) {
+	public addObject(type: string, options: any) {
 		if (this.worker != null) {
-			this.worker.postMessage({ type: 'addObject', objectType: type });
+			this.worker.postMessage({ type: 'addObject', objectType: type, objectOptions: options });
 		} else if (this.engine != null) {
-			this.engine.addObject(type);
+			this.engine.addObject(type, options);
 		}
 	}
 
diff --git a/packages/frontend/src/world/room/engine.ts b/packages/frontend/src/world/room/engine.ts
index ed7f59d214..84882ce79a 100644
--- a/packages/frontend/src/world/room/engine.ts
+++ b/packages/frontend/src/world/room/engine.ts
@@ -125,7 +125,7 @@ export class RoomEngine extends EventEmitter<RoomEngineEvents> {
 	public camera: BABYLON.UniversalCamera;
 	public objectEntities: Map<string, {
 		rootMesh: BABYLON.Mesh;
-		instance: RoomObjectInstance<any>;
+		instance: RoomObjectInstance;
 		model: ModelManager;
 	}> = new Map();
 	private heyaManager: HeyaManager | null = null;
@@ -1433,7 +1433,7 @@ export class RoomEngine extends EventEmitter<RoomEngineEvents> {
 		return ghost;
 	}
 
-	public async addObject(type: string) {
+	public async addObject(type: string, _options?: any) {
 		if (!this.isEditMode) return;
 		if (this.grabbingCtx != null) return;
 		this.selectObject(null);
@@ -1445,7 +1445,7 @@ export class RoomEngine extends EventEmitter<RoomEngineEvents> {
 
 		const def = getObjectDef(type);
 
-		const options = deepClone(def.options.default);
+		const options = _options != null ? deepClone(_options) : deepClone(def.options.default);
 
 		const { root } = await this.loadObject({
 			id: id,
diff --git a/packages/frontend/src/world/room/object.ts b/packages/frontend/src/world/room/object.ts
index 466ae4b473..8b7b14489d 100644
--- a/packages/frontend/src/world/room/object.ts
+++ b/packages/frontend/src/world/room/object.ts
@@ -22,7 +22,7 @@ export type RoomStateObject<Options = any> = {
 	sticky?: string | null;
 };
 
-export type RoomObjectInstance<Options> = {
+export type RoomObjectInstance<Options = any> = {
 	onInited?: () => void;
 	onOptionsUpdated?: <K extends keyof Options, V extends Options[K]>(kv: [K, V]) => void;
 	interactions: Record<string, {
@@ -71,7 +71,12 @@ type ImageOptionSchema = {
 	label: string;
 };
 
-type OptionsSchema = Record<string, NumberOptionSchema | BooleanOptionSchema | ColorOptionSchema | EnumOptionSchema | RangeOptionSchema | ImageOptionSchema>;
+type SeedOptionSchema = {
+	type: 'seed';
+	label: string;
+};
+
+type OptionsSchema = Record<string, NumberOptionSchema | BooleanOptionSchema | ColorOptionSchema | EnumOptionSchema | RangeOptionSchema | ImageOptionSchema | SeedOptionSchema>;
 
 type GetOptionsSchemaValues<T extends OptionsSchema> = {
 	[K in keyof T]:
@@ -81,6 +86,7 @@ type GetOptionsSchemaValues<T extends OptionsSchema> = {
 	T[K] extends EnumOptionSchema ? T[K]['enum'][number] :
 	T[K] extends RangeOptionSchema ? number :
 	T[K] extends ImageOptionSchema ? string | null :
+	T[K] extends SeedOptionSchema ? number :
 	never;
 };
 
diff --git a/packages/frontend/src/world/room/objects/randomBooks.ts b/packages/frontend/src/world/room/objects/randomBooks.ts
index 8802ab7eb3..572fc1374d 100644
--- a/packages/frontend/src/world/room/objects/randomBooks.ts
+++ b/packages/frontend/src/world/room/objects/randomBooks.ts
@@ -33,11 +33,8 @@ export const randomBooks = defineObject({
 				label: 'Stack vertically',
 			},
 			seed: {
-				type: 'range',
+				type: 'seed',
 				label: 'Seed',
-				min: 0,
-				max: 1000,
-				step: 1,
 			},
 		},
 		default: {
@@ -51,7 +48,7 @@ export const randomBooks = defineObject({
 	hasCollisions: false,
 	hasTexture: true,
 	canPreMeshesMerging: false,
-	createInstance: ({ options, model, scene, id }) => {
+	createInstance: ({ options, model, scene }) => {
 		const bodyMesh = model.findMesh('__X_BODY__');
 		const tex = new BABYLON.Texture('/client-assets/room/objects/random-books/texture.png', scene, {
 			invertY: false,
@@ -69,7 +66,7 @@ export const randomBooks = defineObject({
 			}
 			bookMeshes = [];
 
-			const rng = seedrandom(options.seed === 0 ? id : options.seed.toString());
+			const rng = seedrandom(options.seed.toString());
 			const randomRange = (min: number, max: number) => rng() * (max - min) + min;
 
 			let accumulatedPos = 0;
diff --git a/packages/frontend/src/world/room/previewEngine.ts b/packages/frontend/src/world/room/previewEngine.ts
index 8cdb0f1a2a..52ee773dd9 100644
--- a/packages/frontend/src/world/room/previewEngine.ts
+++ b/packages/frontend/src/world/room/previewEngine.ts
@@ -28,7 +28,8 @@ export class RoomObjectPreviewEngine {
 	private shadowGenerator: BABYLON.ShadowGenerator;
 	private camera: BABYLON.ArcRotateCamera;
 	private objectMesh: BABYLON.Mesh | null = null;
-	private objectInstance: RoomObjectInstance<any> | null = null;
+	private objectInstance: RoomObjectInstance | null = null;
+	private objectOptions: any = null;
 	private objectType: string | null = null;
 	private envMapIndoor: BABYLON.CubeTexture;
 	private roomLight: BABYLON.SpotLight;
@@ -152,21 +153,20 @@ export class RoomObjectPreviewEngine {
 	}
 
 	public async load(type: string) {
-		if (this.objectInstance != null) {
-			this.objectInstance.dispose?.();
-			this.objectInstance = null;
-			this.objectMesh!.dispose();
-		}
-
-		const def = getObjectDef(type);
-
-		const options = deepClone(def.options.default);
+		this.clear();
 
 		const id = genId();
+		const def = getObjectDef(type);
+		this.objectOptions = deepClone(def.options.default);
+		for (const [key, value] of Object.entries(def.options.schema)) {
+			if (value.type === 'seed') {
+				this.objectOptions[key] = Math.floor(Math.random() * 1000);
+			}
+		}
 
 		await this.loadObject({
 			type,
-			options,
+			options: this.objectOptions,
 			id,
 		});
 
@@ -214,6 +214,12 @@ export class RoomObjectPreviewEngine {
 			//this.camera.orthoTop = distance;
 			//this.camera.orthoBottom = -distance;
 		}, 10);
+
+		return {
+			id,
+			objectInstance: this.objectInstance,
+			options: this.objectOptions,
+		};
 	}
 
 	private async loadObject(args: {
@@ -236,10 +242,8 @@ export class RoomObjectPreviewEngine {
 
 		root.addChild(subRoot);
 
-		const model = new ModelManager(subRoot, loaderResult.meshes.filter(m => !m.isDisposed() && m !== subRoot), def.hasTexture, (meshes) => {
-			for (const m of meshes) {
-				const mesh = m;
-
+		const updateMeshes = (meshes: BABYLON.AbstractMesh[]) => {
+			for (const mesh of meshes) {
 				// シェイプキー(morph)を考慮してbounding boxを更新するために必要
 				mesh.refreshBoundingInfo({ applyMorph: true });
 
@@ -269,11 +273,14 @@ export class RoomObjectPreviewEngine {
 
 				if (!this.scene.meshes.includes(mesh)) this.scene.addMesh(mesh);
 			}
+		};
+
+		const model = new ModelManager(subRoot, loaderResult.meshes.filter(m => !m.isDisposed() && m !== subRoot), def.hasTexture, (meshes) => {
+			updateMeshes(meshes);
 		});
 
-		if (this.timerForEachObject != null) {
-			this.timerForEachObject.dispose();
-		}
+		updateMeshes(subRoot.getChildMeshes());
+
 		this.timerForEachObject = new Timer();
 
 		const objectInstance = await def.createInstance({
@@ -288,17 +295,31 @@ export class RoomObjectPreviewEngine {
 
 		objectInstance.onInited?.();
 
-		model.bakeMesh();
-
 		this.objectType = args.type;
 		this.objectInstance = objectInstance;
 		this.objectMesh = root;
 	}
 
 	public updateObjectOption(key: string, value: any) {
+		this.objectOptions[key] = value;
 		this.objectInstance?.onOptionsUpdated?.([key, value]);
 	}
 
+	public clear() {
+		if (this.timerForEachObject != null) {
+			this.timerForEachObject.dispose();
+			this.timerForEachObject = null;
+		}
+		if (this.objectInstance != null) {
+			this.objectInstance.dispose?.();
+			this.objectInstance = null;
+			this.objectOptions = null;
+			this.objectMesh!.dispose();
+			this.objectMesh = null;
+			this.objectType = null;
+		}
+	}
+
 	public resize() {
 		this.engine.resize();
 	}
diff --git a/packages/frontend/src/world/utility.ts b/packages/frontend/src/world/utility.ts
index 24a0156791..62b14b0ecd 100644
--- a/packages/frontend/src/world/utility.ts
+++ b/packages/frontend/src/world/utility.ts
@@ -589,3 +589,21 @@ export function getYRotationDirection(rotationY: number): '+x' | '+z' | '-x' | '
 		return '+x';
 	}
 }
+
+export function getHex(c: [number, number, number]) {
+	return `#${c.map(x => Math.round(x * 255).toString(16).padStart(2, '0')).join('')}`;
+}
+
+export function getRgb(hex: string | number): [number, number, number] | null {
+	if (
+		typeof hex === 'number' ||
+		typeof hex !== 'string' ||
+		!/^#([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/.test(hex)
+	) {
+		return null;
+	}
+
+	const m = hex.slice(1).match(/[0-9a-fA-F]{2}/g);
+	if (m == null) return [0, 0, 0];
+	return m.map(x => parseInt(x, 16) / 255) as [number, number, number];
+}