diff -r e628fc2e0c72 -r 03f8e6d42e13 src/tools/transformtool.cpp
--- a/src/tools/transformtool.cpp	Thu Mar 03 21:13:16 2022 +0200
+++ b/src/tools/transformtool.cpp	Fri Mar 04 11:37:50 2022 +0200
@@ -3,13 +3,13 @@
 #include "modeleditcontext.h"
 #include "linetypes/object.h"
 #include "transformtool.h"
+#include "document.h"
 
-TransformTool::TransformTool(Model* model, QWidget* parent) :
-	BaseTool{model, parent},
-	model{model},
-	matrixEditor{new MatrixEditor{parent}},
-	button{new QPushButton{"Apply", parent}},
-	widget{new QWidget{parent}}
+TransformTool::TransformTool(Document* document) :
+	BaseTool{document},
+	matrixEditor{new MatrixEditor{document}},
+	button{new QPushButton{"Apply", document}},
+	widget{new QWidget{document}}
 {
 	widget->setLayout(new QHBoxLayout{widget});
 	widget->layout()->addWidget(this->matrixEditor);
@@ -39,25 +39,22 @@
 
 void TransformTool::applyButtonClicked()
 {
-	Model::EditContext editcontext = this->model->edit();
+	std::unique_ptr<ModelEditor> editor = this->document->editModel();
 	const glm::mat4 matrix = this->matrixEditor->value();
 	for (ldraw::id_t id : this->selection)
 	{
-		const ldraw::Object* object = model->get(id);
-		for (int i = 0; i < object->numPoints(); i += 1)
-		{
-			const ldraw::Property property = ldraw::pointProperty(i);
-			const glm::vec3& vec = matrix * glm::vec4{object->getPoint(i), 1};
-			editcontext.setObjectProperty(id, property, QVariant::fromValue(vec));
-		}
-		QVariant transformMatrix = object->getProperty(ldraw::Property::Transformation);
-		if (not transformMatrix.isNull())
-		{
-			editcontext.setObjectProperty(
-				id,
-				ldraw::Property::Transformation,
-				QVariant::fromValue(matrix * transformMatrix.value<glm::mat4>())
-			);
-		}
+		editor->modifyObject(id, [&](ldraw::Object* object){
+			for (int i = 0; i < object->numPoints(); i += 1)
+			{
+				const ldraw::Property property = ldraw::pointProperty(i);
+				const glm::vec3& vec = matrix * glm::vec4{object->getPoint(i), 1};
+				object->setProperty({property, QVariant::fromValue(vec)});
+			}
+			QVariant transformMatrix = object->getProperty(ldraw::Property::Transformation);
+			if (not transformMatrix.isNull())
+			{
+				object->setProperty<ldraw::Property::Transformation>(matrix * transformMatrix.value<glm::mat4>());
+			}
+		});
 	}
 }