diff -r 7c27cda03747 -r 97df974b5ed5 src/model.h
--- a/src/model.h	Fri Mar 06 23:45:44 2020 +0200
+++ b/src/model.h	Mon Mar 09 14:21:54 2020 +0200
@@ -44,19 +44,33 @@
 	const QString& getName() const;
 	QVariant getObjectProperty(const int index, const ldraw::Property property) const;
 	std::vector<gl::Polygon> getPolygons(class DocumentManager* documents) const;
-	QModelIndex lookup(ldraw::Id id) const;
-	ldraw::Id resolve(const QModelIndex& index) const;
+	QModelIndex lookup(ldraw::id_t id) const;
+	ldraw::id_t resolve(const QModelIndex& index) const;
+	template<typename R>
+	ldraw::Id<R> checkType(ldraw::id_t id) const;
+	template<typename R>
+	const R* get(ldraw::Id<R> id) const;
 signals:
-	void objectAdded(ldraw::Id id, int position);
+	void objectAdded(ldraw::id_t id, int position);
 private:
 	using ModelObjectPointer = std::unique_ptr<ldraw::Object>;
 	template<typename T, typename... Args>
-	ldraw::Id append(Args&&... args);
+	ldraw::Id<T> append(Args&&... args);
 	void append(ModelObjectPointer&& object);
 	template<typename T, typename... Args>
-	ldraw::Id insert(int position, Args&&... args);
+	ldraw::Id<T> insert(int position, Args&&... args);
 	ldraw::Object* objectAt(const QModelIndex& index);
 	const ldraw::Object* objectAt(const QModelIndex& index) const;
+	template<typename T>
+	T* objectAt(ldraw::Id<T> id)
+	{
+		return static_cast<T*>(this->objectAt(this->lookup(id)));
+	}
+	template<typename T>
+	const T* objectAt(ldraw::Id<T> id) const
+	{
+		return static_cast<const T*>(this->objectAt(this->lookup(id)));
+	}
 	void getObjectPolygons(
 		const int index,
 		std::vector<gl::Polygon>& polygons_out,
@@ -65,13 +79,31 @@
 	QString path;
 	LDHeader header;
 	std::vector<ModelObjectPointer> body;
-	std::map<ldraw::Id, ldraw::Object*> objectsById;
+	std::map<ldraw::id_t, ldraw::Object*> objectsById;
 	mutable std::vector<gl::Polygon> cachedPolygons;
 	mutable bool needRecache = true;
 };
 
+/**
+ * \brief Checks type of object behind id
+ * Checks whether the specified id refers to an object of the specified type.
+ * \returns id casted to subclass if appropriate, null id otherwise
+ */
+template<typename R>
+ldraw::Id<R> Model::checkType(ldraw::id_t id) const
+{
+	if (dynamic_cast<const R*>(this->objectAt(this->lookup(id))) != nullptr)
+	{
+		return ldraw::Id<R>{id.value};
+	}
+	else
+	{
+		return ldraw::NULL_ID;
+	}
+}
+
 template<typename T, typename... Args>
-ldraw::Id Model::append(Args&&... args)
+ldraw::Id<T> Model::append(Args&&... args)
 {
 	emit layoutAboutToBeChanged();
 	this->body.push_back(std::make_unique<T>(args...));
@@ -79,11 +111,11 @@
 	this->objectsById[pointer->id] = pointer;
 	emit objectAdded(pointer->id, this->body.size() - 1);
 	emit layoutChanged();
-	return pointer->id;
+	return ldraw::Id<T>{pointer->id};
 }
 
 template<typename T, typename... Args>
-ldraw::Id Model::insert(int position, Args&&... args)
+ldraw::Id<T> Model::insert(int position, Args&&... args)
 {
 	emit layoutAboutToBeChanged();
 	this->body.insert(position, std::make_unique<T>(args...));
@@ -91,5 +123,11 @@
 	this->objectsById[pointer->id] = pointer;
 	emit objectAdded(pointer->id, position);
 	emit layoutChanged();
-	return pointer->id;
+	return ldraw::Id<T>{pointer->id};
 }
+
+template<typename R>
+const R* Model::get(ldraw::Id<R> id) const
+{
+	return this->objectAt(id);
+}