diff -r e6faeffed1d1 -r b4beff48bb7a src/polygoncache.cpp
--- a/src/polygoncache.cpp	Wed May 25 17:25:24 2022 +0300
+++ b/src/polygoncache.cpp	Wed May 25 17:42:02 2022 +0300
@@ -1,14 +1,11 @@
 #include "polygoncache.h"
 #include "documentmanager.h"
 
-PolygonCache::PolygonCache(Model *model) :
-	model{model}
-{
-	const auto mark = [this](){ this->needRecache = true; };
-	connect(model, &Model::dataChanged, mark);
-	connect(model, &Model::rowsInserted, mark);
-	connect(model, &Model::rowsRemoved, mark);
-}
+static void getObjectPolygons(
+	Model* model,
+	const int index,
+	std::vector<gl::Polygon>& polygons_out,
+	ldraw::GetPolygonsContext* context);
 
 /**
  * @brief Gets a list of GL polygons that are used to represent this model.
@@ -16,23 +13,26 @@
  * @param documents Documents to use to resolve subfile references
  * @return vector of GL polygons
  */
-const std::vector<gl::Polygon> &PolygonCache::getPolygons(DocumentManager* documents)
+const std::vector<gl::Polygon> &getCachedPolygons(
+	PolygonCache *cache,
+	Model *model,
+	DocumentManager *documents)
 {
-	if (this->needRecache)
+	if (cache->needRecache)
 	{
-		this->cachedPolygons.clear();
-		const std::optional<ModelId> modelId = documents->findIdForModel(this->model);
+		cache->cachedPolygons.clear();
+		const std::optional<ModelId> modelId = documents->findIdForModel(model);
 		if (modelId.has_value())
 		{
 			ldraw::GetPolygonsContext context{modelId.value(), documents};
-			for (int i = 0; i < this->model->size(); i += 1)
+			for (int i = 0; i < model->size(); i += 1)
 			{
-				this->getObjectPolygons(i, this->cachedPolygons, &context);
+				getObjectPolygons(model, i, cache->cachedPolygons, &context);
 			}
 		}
-		this->needRecache = false;
+		cache->needRecache = false;
 	}
-	return this->cachedPolygons;
+	return cache->cachedPolygons;
 }
 
 /**
@@ -41,11 +41,12 @@
  * @param polygons_out Vector to add polygons into
  * @param context Context to use to resolve subfile references
  */
-void PolygonCache::getObjectPolygons(
+static void getObjectPolygons(
+	Model* model,
 	const int index,
 	std::vector<gl::Polygon>& polygons_out,
-	ldraw::GetPolygonsContext* context) const
+	ldraw::GetPolygonsContext* context)
 {
-	const ldraw::Object* object = (*this->model)[unsigned_cast(index)];
+	const ldraw::Object* object = (*model)[unsigned_cast(index)];
 	object->getPolygons(polygons_out, context);
 }