diff -r e1ced2523cad -r b6cbba6e29a1 src/model.cpp
--- a/src/model.cpp	Tue Nov 02 15:43:57 2021 +0200
+++ b/src/model.cpp	Thu Mar 03 11:42:52 2022 +0200
@@ -32,7 +32,6 @@
 Model::Model(QObject *parent) :
 	QAbstractListModel{parent}
 {
-	connect(this, &Model::dataChanged, [&](){ this->needRecache = true; });
 }
 
 /**
@@ -132,36 +131,11 @@
 }
 
 /**
- * @brief Gets a list of GL polygons that are used to represent this model.
- * @details Will build polygons if polygons are outdated.
- * @param documents Documents to use to resolve subfile references
- * @return vector of GL polygons
- */
-std::vector<gl::Polygon> Model::getPolygons(DocumentManager* documents) const
-{
-	if (this->needRecache)
-	{
-		this->cachedPolygons.clear();
-		const std::optional<ModelId> modelId = documents->findIdForModel(this);
-		if (modelId.has_value())
-		{
-			ldraw::GetPolygonsContext context{modelId.value(), documents};
-			for (int i = 0; i < this->size(); i += 1)
-			{
-				this->getObjectPolygons(i, this->cachedPolygons, &context);
-			}
-		}
-		this->needRecache = false;
-	}
-	return this->cachedPolygons;
-}
-
-/**
  * @brief Finds the position of the specified object in the model
  * @param id Object id to look for
  * @return model index
  */
-QModelIndex Model::lookup(ldraw::id_t id) const
+QModelIndex Model::find(ldraw::id_t id) const
 {
 	// FIXME: This linear search will probably cause performance issues
 	for (std::size_t i = 0; i < this->body.size(); i += 1)
@@ -179,7 +153,7 @@
  * @param index Position of the object in the model
  * @return id
  */
-ldraw::id_t Model::resolve(const QModelIndex& index) const
+ldraw::id_t Model::idAt(const QModelIndex& index) const
 {
 	return this->objectAt(index)->id;
 }
@@ -211,21 +185,6 @@
 #endif
 
 /**
- * @brief Gets the GL polygons of the object at the specified position in the model
- * @param index Index of object in the model
- * @param polygons_out Vector to add polygons into
- * @param context Context to use to resolve subfile references
- */
-void Model::getObjectPolygons(
-	const int index,
-	std::vector<gl::Polygon>& polygons_out,
-	ldraw::GetPolygonsContext* context) const
-{
-	const ldraw::Object* object = this->body[unsigned_cast(index)].get();
-	object->getPolygons(polygons_out, context);
-}
-
-/**
  * @brief Called by the editing context to signal to the model that editing is done.
  */
 void Model::editFinished()
@@ -239,7 +198,7 @@
  */
 void Model::objectModified(ldraw::id_t id)
 {
-	const QModelIndex index = this->lookup(id);
+	const QModelIndex index = this->find(id);
 	Q_EMIT this->dataChanged(index, index);
 }
 
@@ -250,10 +209,10 @@
 void Model::append(ModelObjectPointer&& object)
 {
 	const int position = static_cast<int>(this->body.size());
-	Q_EMIT beginInsertRows({}, position, position);
+	Q_EMIT this->beginInsertRows({}, position, position);
 	this->body.push_back(std::move(object));
-	Q_EMIT endInsertRows();
-	this->needRecache = true;
+	Q_EMIT this->endInsertRows();
+	Q_EMIT this->objectAdded(position);
 }
 
 /**
@@ -264,10 +223,11 @@
 {
 	if (position >= 0 and position < signed_cast(this->body.size()))
 	{
-		Q_EMIT beginRemoveRows({}, position, position);
+		Q_EMIT this->beginRemoveRows({}, position, position);
+		const ldraw::id_t id = this->body[position]->id;
 		this->body.erase(std::begin(this->body) + position);
-		Q_EMIT endRemoveRows();
-		this->needRecache = true;
+		Q_EMIT this->endRemoveRows();
+		Q_EMIT this->objectRemoved(id);
 	}
 }
 
@@ -303,29 +263,42 @@
 	}
 }
 
+ldraw::Object* Model::operator[](int index)
+{
+	if (index >= 0 and index < this->size())
+	{
+		return this->body[index].get();
+	}
+	else
+	{
+		throw std::out_of_range{"index out of range"};
+	}
+}
+
 /**
  * @brief Modifies the !LDRAW_ORG line so that it becomes unofficial
  */
-void Model::makeUnofficial()
+void makeUnofficial(Model& model)
 {
-	if (this->body.size() >= 4)
+	if (model.size() >= 4)
 	{
-		const ldraw::id_t id = this->body[3]->id;
-		if (this->isA<ldraw::MetaCommand>(id))
+		const ldraw::Object* ldrawOrgLine = model[3];
+		if (isA<ldraw::MetaCommand>(ldrawOrgLine))
 		{
-			const QString& body = this->body[3]->getProperty<ldraw::Property::Text>();
+			const QString& body = ldrawOrgLine->getProperty<ldraw::Property::Text>();
 			if (body.startsWith("!LDRAW_ORG ") and not body.startsWith("!LDRAW_ORG Unofficial_"))
 			{
+				// Add Unofficial_ to part type
 				QStringList tokens = body.split(" ");
 				tokens[1] = "Unofficial_" + tokens[1];
-				// Remove the UPDATE tag
+				// Remove the UPDATE tag if it's there
 				if (tokens.size() >= 4 && tokens[2] == "UPDATE")
 				{
 					tokens.removeAt(3);
 					tokens.removeAt(2);
 				}
-				EditContext editor = this->edit();
-				editor.setObjectProperty<ldraw::Property::Text>(id, tokens.join(" "));
+				Model::EditContext editor = model.edit();
+				editor.setObjectProperty<ldraw::Property::Text>(ldrawOrgLine->id, tokens.join(" "));
 			}
 		}
 	}