diff -r e1ced2523cad -r b6cbba6e29a1 src/documentmanager.h
--- a/src/documentmanager.h	Tue Nov 02 15:43:57 2021 +0200
+++ b/src/documentmanager.h	Thu Mar 03 11:42:52 2022 +0200
@@ -19,6 +19,7 @@
 #pragma once
 #include "libraries.h"
 #include "model.h"
+#include "polygoncache.h"
 
 class DocumentManager : public QObject
 {
@@ -55,10 +56,12 @@
 			QTextStream &errorStream);
 	bool saveModel(const ModelId modelId, QTextStream& errors);
 	std::optional<ModelId> findIdForModel(const Model* model) const;
+	PolygonCache* getPolygonCacheForModel(ModelId modelId);
 private:
 	struct ModelInfo
 	{
 		std::unique_ptr<Model> model;
+		ModelId id;
 		QString path;
 		OpenType opentype;
 		std::map<QString, ModelId> dependencies = {};
@@ -67,11 +70,13 @@
 	int modelIdCounter = 0;
 	int untitledNameCounter = 0;
 	std::map<ModelId, ModelInfo> openModels;
+	std::map<ModelId, PolygonCache> polygonCaches;
 	void loadDependenciesForModel(const ModelId modelId, const QString& path, LoadDepedenciesBag& bag);
 	void collectReferences(QSet<QString> &referenced, const QString& name, const Model* model);
 	void updateDependencies(ModelInfo* model);
 	void prune();
 	bool isReferencedByAnything(const ModelId modelId) const;
+	void makePolygonCacheForModel(const ModelId modelId);
 };
 
 QString pathToName(const QFileInfo& path);