diff -r 0f80a2e5e42b -r 1a9eac27698d src/model.h
--- a/src/model.h	Fri Feb 07 02:02:16 2020 +0200
+++ b/src/model.h	Fri Feb 07 23:59:06 2020 +0200
@@ -44,7 +44,8 @@
 	const QString& getName() const;
 	QVariant getObjectProperty(const int index, const ldraw::Property property) const;
 	std::vector<gl::Polygon> getPolygons(class DocumentManager* documents) const;
-	void getObjectPolygons(const int index, std::vector<gl::Polygon>& polygons_out, ldraw::GetPolygonsContext* context) const;
+	QModelIndex lookup(ldraw::Id id) const;
+	ldraw::Id resolve(const QModelIndex& index) const;
 signals:
 	void objectAdded(ldraw::Id id, int position);
 private:
@@ -54,6 +55,12 @@
 	void append(ModelObjectPointer&& object);
 	template<typename T, typename... Args>
 	ldraw::Id insert(int position, Args&&... args);
+	ldraw::Object* objectAt(const QModelIndex& index);
+	const ldraw::Object* objectAt(const QModelIndex& index) const;
+	void getObjectPolygons(
+		const int index,
+		std::vector<gl::Polygon>& polygons_out,
+		ldraw::GetPolygonsContext* context) const;
 	bool modified = false;
 	QString path;
 	LDHeader header;