diff -r 03f8e6d42e13 -r 2f79053c2e9a src/modeleditor.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/modeleditor.cpp	Fri Mar 04 11:40:19 2022 +0200
@@ -0,0 +1,85 @@
+/*
+ *  LDForge: LDraw parts authoring CAD
+ *  Copyright (C) 2013 - 2020 Teemu Piippo
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "modeleditor.h"
+#include "linetypes/triangle.h"
+#include "linetypes/quadrilateral.h"
+
+ModelEditor::ModelEditor(Model& model) :
+	storedModel{model}
+{
+}
+
+ModelEditor::~ModelEditor()
+{
+	for (ldraw::id_t id : this->modifiedObjects)
+	{
+		const QModelIndex index = this->model().find(id);
+		if (index.isValid())
+		{
+			Q_EMIT this->objectModified(index.row());
+		}
+	}
+}
+
+ldraw::id_t ModelEditor::append(std::unique_ptr<ldraw::Object>&& object)
+{
+	this->storedModel.append(std::move(object));
+	Q_EMIT this->objectAdded(this->model().size() - 1);
+	return object->id;
+}
+
+void ModelEditor::remove(int position)
+{
+	this->storedModel.remove(position);
+}
+
+auto ModelEditor::setObjectProperty(
+	const ldraw::id_t id,
+	const ldraw::Property property,
+	const QVariant& value)
+	-> ldraw::Object::SetPropertyResult
+{
+	ldraw::Object* const object = this->storedModel.findObjectById(id);
+	if (object != nullptr)
+	{
+		const ldraw::Object::SetPropertyResult result = object->setProperty(ldraw::PropertyKeyValue{property, value});
+		modifiedObjects.insert(id);
+		return result;
+	}
+	else
+	{
+		return ldraw::Object::SetPropertyResult::PropertyNotHandled;
+	}
+}
+
+void ModelEditor::setObjectPoint(ldraw::id_t id, int pointId, const glm::vec3& value)
+{
+	ldraw::Object* object = this->storedModel.findObjectById(id);
+	if (object != nullptr)
+	{
+		object->setProperty(ldraw::PropertyKeyValue{ldraw::pointProperty(pointId), QVariant::fromValue(value)});
+		modifiedObjects.insert(id);
+	}
+}
+
+const Model &ModelEditor::model()
+{
+	return this->storedModel;
+}
+