diff --git a/qglengine/globject.cpp b/qglengine/globject.cpp
index 1e4f192..44d5ce4 100644
--- a/qglengine/globject.cpp
+++ b/qglengine/globject.cpp
@@ -51,6 +51,7 @@ ObjectBase::~ObjectBase() {
 	if (scene_) {
 		scene_->__objectDeleted(this);
 		scene_->setTreeChanged();
+		scene_->setTreeStructChanged();
 	}
 	foreach (ObjectBase * c, children_) {
 		c->parent_ = nullptr;
@@ -364,6 +365,8 @@ void ObjectBase::setColor(QColor c, bool with_children) {
 
 
 void ObjectBase::setMesh(Mesh * v) {
+	if (scene_)
+		v = scene_->attachMesh(v);
 	mesh_ = v;
 	setSceneTreeChanged();
 	setObjectsChanged();
diff --git a/qglengine/glscene.cpp b/qglengine/glscene.cpp
index 0759a42..2674b26 100644
--- a/qglengine/glscene.cpp
+++ b/qglengine/glscene.cpp
@@ -171,6 +171,7 @@ void Scene::removeObject(ObjectBase & o, bool inChildren) {
 
 void Scene::clearObjects(bool deleteAll) {
 	root_->clearChildren(deleteAll);
+	cleanUnused();
 	setTreeStructChanged();
 	emitSelectionChanged();
 }
@@ -253,6 +254,20 @@ ObjectBase * Scene::selectedObject() const {
 }
 
 
+void Scene::cleanUnused() {
+	QSet<Mesh*> ums;
+	QMapIterator<int, QMap<Mesh*, ObjectBaseList>> it(geometries_used);
+	while (it.hasNext())
+		ums |= it.next().value().keys().toSet();
+	for (int i = 0; i < geometries.size(); ++i) {
+		if (ums.contains(geometries[i])) continue;
+		td_geometries << geometries[i];
+		geometries.removeAt(i);
+		--i;
+	}
+}
+
+
 const Box3D & Scene::boundingBox() const {
 	root_->calculateBoundingBox();
 	return root_->boundingBox();
@@ -319,25 +334,8 @@ void Scene::attachObject(ObjectBase * o) {
 	if (!o) return;
 	o->setScene(this);
 	if (o->mesh()) { // search suitable mesh in this scene
-		uint ohash = o->mesh()->hash();
-		bool need_new = true;
-		foreach (Mesh * m, geometries) {
-			if (m == o->mesh()) { // already exists by ptr
-				need_new = false;
-				setObjectMeshChanged(o);
-				break;
-			}
-			if (m->hash() == ohash) { // already exists by hash
-				need_new = false;
-				o->setMesh(m);
-				break;
-			}
-		}
-		if (need_new) { // need to clone mesh and add to scene
-			Mesh * nmesh = o->mesh()->clone();
-			o->setMesh(nmesh);
-			geometries << nmesh;
-		}
+		o->mesh_ = attachMesh(o->mesh());
+		setObjectMeshChanged(o);
 	}
 	if (o->material()) { // search suitable material in this scene
 		uint ohash = o->material()->hash();
@@ -361,6 +359,25 @@ void Scene::attachObject(ObjectBase * o) {
 			materials << nmat;
 		}
 	}
+	setTreeStructChanged();
+}
+
+
+Mesh * Scene::attachMesh(Mesh * mesh) {
+	if (!mesh) return 0;
+	uint mhash = mesh->hash();
+	foreach (Mesh * m, geometries) {
+		if (m == mesh) { // already exists by ptr
+			return m;
+		}
+		if (m->hash() == mhash) { // already exists by hash
+			return m;
+		}
+	}
+	// need to clone mesh and add to scene
+	Mesh * nmesh = mesh->clone();
+	geometries << nmesh;
+	return nmesh;
 }
 
 
@@ -421,14 +438,15 @@ bool Scene::prepare() {
 	if (tree_changed) {
 		tree_changed = false;
 		lights_changed = true;
-		if (tree_struct_changed) {
-			tree_struct_changed = false;
-			QMetaObject::invokeMethod(this, "treeChanged", Qt::QueuedConnection);
-		}
 		geometries_used[rpSolid      ].clear();
 		geometries_used[rpTransparent].clear();
 		lights_used.clear();
 		prepareTree(root_);
+		if (tree_struct_changed) {
+			tree_struct_changed = false;
+			cleanUnused();
+			QMetaObject::invokeMethod(this, "treeChanged", Qt::QueuedConnection);
+		}
 	}
 	mat_changed = false;
 	return true;
@@ -440,7 +458,7 @@ void Scene::destroy() {
 	selected_top.clear();
 	emitSelectionChanged();
 	root_->clearChildren(true);
-	qDeleteAll(geometries);
+	td_geometries << geometries;
 	qDeleteAll(materials);
 	geometries.clear();
 	materials.clear();
@@ -449,6 +467,15 @@ void Scene::destroy() {
 }
 
 
+void Scene::destroyUnused(QOpenGLExtraFunctions * f) {
+	if (!td_geometries.isEmpty()) qDebug() << "destroyUnused" << td_geometries.size();
+	foreach (Mesh * i, td_geometries)
+		i->destroy(f);
+	qDeleteAll(td_geometries);
+	td_geometries.clear();
+}
+
+
 QDataStream & operator <<(QDataStream & s, const Scene * p) {
 	ChunkStream cs;
 	//qDebug() << "place" << p->name() << "...";
diff --git a/qglengine/glscene.h b/qglengine/glscene.h
index 3df3520..212660b 100644
--- a/qglengine/glscene.h
+++ b/qglengine/glscene.h
@@ -77,6 +77,7 @@ public:
 	void clearSelection();
 	ObjectBaseList selectedObjects(bool top_only = false) const;
 	ObjectBase * selectedObject() const;
+	void cleanUnused();
 
 	const Box3D & boundingBox() const;
 
@@ -89,6 +90,7 @@ public:
 
 	void dump();
 	void destroy();
+	void destroyUnused(QOpenGLExtraFunctions * f);
 
 protected:
 	void prepareTree(ObjectBase * o);
@@ -99,6 +101,7 @@ protected:
 	QString uniqueName(QString n, const QSet<QString> & names);
 
 	void attachObject(ObjectBase * o);
+	Mesh * attachMesh(Mesh * mesh);
 	void setTreeChanged();
 	void setTreeStructChanged();
 	void setMaterialsChanged() {mat_changed = true;}
@@ -112,7 +115,7 @@ protected:
 	bool need_reload_materials, tree_struct_changed;
 	QVector<bool> mat_map_changed;
 
-	QVector<Mesh*> geometries;
+	QVector<Mesh*> geometries, td_geometries;
 	QVector<Material*> materials;
 
 	QMap<int, QMap<Mesh*, ObjectBaseList>> geometries_used; // [pass][mesh] = ObjectBaseList
diff --git a/qglengine/renderer.cpp b/qglengine/renderer.cpp
index 89ebad8..759cc63 100644
--- a/qglengine/renderer.cpp
+++ b/qglengine/renderer.cpp
@@ -255,6 +255,7 @@ void Renderer::renderScene() {
 	Camera * cam = view->camera();
 	QOpenGLShaderProgram * prog = 0;
 	bool scene_changed = scene.prepare();
+	scene.destroyUnused(f);
 
 	/// reload materials on change
 	if (scene_changed || scene.need_reload_materials) {
@@ -332,7 +333,6 @@ void Renderer::renderScene() {
 	if (bindShader(srTonemapPass, &prog)) {
 		prog->setUniformValue("gamma", gamma_);
 		prog->setUniformValue("frame_max", tone_proc.frameMax());
-		//fbo_1x1.bindColorTexture(0, 1);
 		fbo_out.bindColorTexture(obrSum, 0);
 		fbo_out.setWriteBuffer(obrTonemap);
 		renderQuad(prog, quad);