diff -r ed73c4f48ca4 -r 4a754362f660 src/model.h
--- a/src/model.h	Sat Feb 04 14:24:16 2017 +0200
+++ b/src/model.h	Sat Feb 04 14:44:39 2017 +0200
@@ -1,7 +1,28 @@
+/*
+ *  LDForge: LDraw parts authoring CAD
+ *  Copyright (C) 2013 - 2017 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/>.
+ */
+
 #pragma once
 #include "main.h"
 #include "ldObject.h"
 
+/*
+ * This class represents a LDraw model, consisting of a vector of objects. It manages LDObject ownership.
+ */
 class Model
 {
 public:
@@ -9,10 +30,14 @@
 	Model(const Model& other) = delete;
 	~Model();
 
-	virtual void addObject(LDObject* object);
+	void addObject(LDObject* object);
 	virtual void insertObject(int position, LDObject* object);
 	virtual bool swapObjects(LDObject* one, LDObject* other);
 	virtual bool setObjectAt(int idx, LDObject* obj);
+	template<typename T, typename... Args> T* emplace(Args&& ...args);
+	template<typename T, typename... Args> T* emplaceAt(int position, Args&& ...args);
+	template<typename T, typename... Args> T* emplaceReplacement(LDObject* object, Args&& ...args);
+	template<typename T, typename... Args> T* emplaceReplacementAt(int position, Args&& ...args);
 	void removeAt(int position);
 	void remove(LDObject* object);
 	void replace(LDObject *object, Model& model);
@@ -31,59 +56,8 @@
 	LDObject* addFromString(QString line);
 	LDObject* replaceWithFromString(LDObject* object, QString line);
 
-	template<typename T, typename... Args>
-	T* emplace(Args&& ...args)
-	{
-		T* object = constructObject<T>(args...);
-		addObject(object);
-		return object;
-	}
-
-	template<typename T, typename... Args>
-	T* emplaceAt(int position, Args&& ...args)
-	{
-		T* object = constructObject<T>(args...);
-		insertObject(position, object);
-		return object;
-	}
-
-	template<typename T, typename... Args>
-	T* emplaceReplacement(LDObject* object, Args&& ...args)
-	{
-		if (object->model() == this)
-		{
-			int position = object->lineNumber();
-			T* replacement = constructObject<T>(args...);
-			setObjectAt(position, replacement);
-			return replacement;
-		}
-		else
-			return nullptr;
-	}
-
-	template<typename T, typename... Args>
-	T* emplaceReplacementAt(int position, Args&& ...args)
-	{
-		T* replacement = constructObject<T>(args...);
-		setObjectAt(position, replacement);
-		return replacement;
-	}
-
 protected:
-	template<typename T, typename... Args>
-	T* constructObject(Args&& ...args)
-	{
-		static_assert (std::is_base_of<LDObject, T>::value, "Can only use this function with LDObject-derivatives");
-		T* object = new T {args..., this};
-
-		// Set default color. Relying on virtual functions, this cannot be done in the c-tor.
-		// TODO: store -1 as the default color
-		if (object->isColored())
-			object->setColor(object->defaultColor());
-
-		return object;
-	}
-
+	template<typename T, typename... Args> T* constructObject(Args&& ...args);
 	void withdraw(LDObject* object);
 	virtual LDObject* withdrawAt(int position);
 
@@ -94,3 +68,83 @@
 };
 
 int countof(Model& model);
+
+/*
+ * Given an LDObject type as the template parameter, and any number of variadic parameters, constructs an LDObject derivative
+ * and inserts it into this model. The variadic parameters and this model pointer are passed to the constructor. The constructed object
+ * is added to the end of the model.
+ *
+ * For instance, the LDLine contains a constructor as such:
+ *
+ *     LDLine(Vertex v1, Vertex v2, Model* model);
+ *
+ * This constructor can be invoked as such:
+ *
+ *     model->emplace<LDLine>(v1, v2);
+ */
+template<typename T, typename... Args>
+T* Model::emplace(Args&& ...args)
+{
+	T* object = constructObject<T>(args...);
+	addObject(object);
+	return object;
+}
+
+/*
+ * Like emplace<>() but also takes a position as the first argument and emplaces the object at the given position instead of the
+ * end of the model.
+ */
+template<typename T, typename... Args>
+T* Model::emplaceAt(int position, Args&& ...args)
+{
+	T* object = constructObject<T>(args...);
+	insertObject(position, object);
+	return object;
+}
+
+/*
+ * Like emplace<>() but instead of inserting the constructed object, the new object replaces the object given in the first parameter.
+ * If the old object cannot be replaced, the new object will not be constructed at all.
+ */
+template<typename T, typename... Args>
+T* Model::emplaceReplacement(LDObject* object, Args&& ...args)
+{
+	if (object->model() == this)
+	{
+		int position = object->lineNumber();
+		T* replacement = constructObject<T>(args...);
+		setObjectAt(position, replacement);
+		return replacement;
+	}
+	else
+		return nullptr;
+}
+
+/*
+ * Like emplaceAt<>() but instead of inserting the constructed object, it replaces the document at the given spot instead.
+ * The replaced object is deleted in the process.
+ */
+template<typename T, typename... Args>
+T* Model::emplaceReplacementAt(int position, Args&& ...args)
+{
+	T* replacement = constructObject<T>(args...);
+	setObjectAt(position, replacement);
+	return replacement;
+}
+
+/*
+ * Constructs an LDObject such that it gets this model as its model pointer.
+ */
+template<typename T, typename... Args>
+T* Model::constructObject(Args&& ...args)
+{
+	static_assert (std::is_base_of<LDObject, T>::value, "Can only use this function with LDObject-derivatives");
+	T* object = new T {args..., this};
+
+	// Set default color. Relying on virtual functions, this cannot be done in the c-tor.
+	// TODO: store -1 as the default color
+	if (object->isColored())
+		object->setColor(object->defaultColor());
+
+	return object;
+}
\ No newline at end of file