diff --git a/common/camera.cpp b/common/camera.cpp
index 94f32f36..fe4cb618 100644
--- a/common/camera.cpp
+++ b/common/camera.cpp
@@ -13,6 +13,11 @@
 
 #define LC_CAMERA_SAVE_VERSION 7 // LeoCAD 0.80
 
+lcCamera::lcCamera()
+    : lcObject(lcObjectType::Camera)
+{
+}
+
 lcCamera::lcCamera(bool Simple)
     : lcObject(lcObjectType::Camera), mSimple(Simple)
 {
@@ -26,8 +31,8 @@ lcCamera::lcCamera(bool Simple)
 	}
 }
 
-lcCamera::lcCamera(const lcVector3& Position, const lcVector3& TargetPosition)
-	: lcObject(lcObjectType::Camera)
+lcCamera::lcCamera(bool Simple, const lcVector3& Position, const lcVector3& TargetPosition)
+    : lcObject(lcObjectType::Camera), mSimple(Simple)
 {
 	// Fix the up vector
 	lcVector3 UpVector(0, 0, 1), FrontVector(Position - TargetPosition), SideVector;
@@ -893,33 +898,38 @@ void lcCamera::RemoveKeyFrames()
 	mUpVector.RemoveAllKeys();
 }
 
-bool lcCamera::SaveUndoData(QDataStream& Stream, const lcModel* Model) const
+lcCameraHistoryState lcCamera::GetHistoryState(const lcModel* Model) const
 {
-	static_assert(sizeof(lcCamera) == 248);
-	Q_UNUSED(Model);
+	lcCameraHistoryState State;
 	
-	Stream << m_fovy;
-	Stream << m_zNear;
-	Stream << m_zFar;
-	Stream << mName;
-	Stream << mProjection;
-	Stream << mHidden;
-
-	return mPosition.SaveUndoData(Stream) && mTargetPosition.SaveUndoData(Stream) && mUpVector.SaveUndoData(Stream);
+	State.Id = mId;
+	State.Hidden = mHidden;
+	State.Simple = mSimple;
+	State.Fovy = m_fovy;
+	State.NearPlane = m_zNear;
+	State.FarPlane = m_zFar;
+	State.Projection = mProjection;
+	State.Position = mPosition;
+	State.TargetPosition = mTargetPosition;
+	State.UpVector = mUpVector;
+	State.Name = mName;
+	
+	return State;
 }
 
-bool lcCamera::LoadUndoData(QDataStream& Stream, const lcModel* Model)
+void lcCamera::SetHistoryState(const lcCameraHistoryState& State, const lcModel* Model)
 {
-	Q_UNUSED(Model);
-	
-	Stream >> m_fovy;
-	Stream >> m_zNear;
-	Stream >> m_zFar;
-	Stream >> mName;
-	Stream >> mProjection;
-	Stream >> mHidden;
-
-	return mPosition.LoadUndoData(Stream) && mTargetPosition.LoadUndoData(Stream) && mUpVector.LoadUndoData(Stream);
+	mId = State.Id;
+	mHidden = State.Hidden;
+	mSimple = State.Simple;
+	m_fovy = State.Fovy;
+	m_zNear = State.NearPlane;
+	m_zFar = State.FarPlane;
+	mProjection = State.Projection;
+	mPosition = State.Position;
+	mTargetPosition = State.TargetPosition;
+	mUpVector = State.UpVector;
+	mName = State.Name;
 }
 
 void lcCamera::RayTest(lcObjectRayTest& ObjectRayTest) const
diff --git a/common/camera.h b/common/camera.h
index 9890a695..f0bc2d01 100644
--- a/common/camera.h
+++ b/common/camera.h
@@ -30,11 +30,34 @@ enum lcCameraSection : quint32
 	LC_CAMERA_SECTION_UPVECTOR
 };
 
+struct lcCameraHistoryState
+{
+	lcObjectId Id;
+	bool Hidden;
+	bool Simple;
+	float Fovy;
+	float NearPlane;
+	float FarPlane;
+	lcCameraProjection Projection;
+	lcObjectProperty<lcVector3> Position;
+	lcObjectProperty<lcVector3> TargetPosition;
+	lcObjectProperty<lcVector3> UpVector;
+	QString Name;
+	
+	bool operator==(const lcCameraHistoryState& Other) const
+	{
+		return Id == Other.Id && Hidden == Other.Hidden && Simple == Other.Simple && Fovy == Other.Fovy &&
+            NearPlane == Other.NearPlane && FarPlane == Other.FarPlane && Projection == Other.Projection &&
+            Position == Other.Position && TargetPosition == Other.TargetPosition && UpVector == Other.UpVector && Name == Other.Name;
+	}
+};
+
 class lcCamera : public lcObject
 {
 public:
+	lcCamera();
 	lcCamera(bool Simple);
-	lcCamera(const lcVector3& Position, const lcVector3& TargetPosition);
+	lcCamera(bool Simple, const lcVector3& Position, const lcVector3& TargetPosition);
 	virtual ~lcCamera();
 
 	lcCamera(const lcCamera&) = delete;
@@ -167,8 +190,8 @@ public:
 	bool HasKeyFrame(lcObjectPropertyId PropertyId, lcStep Time) const override;
 	bool SetKeyFrame(lcObjectPropertyId PropertyId, lcStep Time, bool KeyFrame) override;
 	void RemoveKeyFrames() override;
-	bool SaveUndoData(QDataStream& Stream, const lcModel* Model) const override;
-	bool LoadUndoData(QDataStream& Stream, const lcModel* Model) override;
+	lcCameraHistoryState GetHistoryState(const lcModel* Model) const;
+	void SetHistoryState(const lcCameraHistoryState& State, const lcModel* Model);
 
 	void InsertTime(lcStep Start, lcStep Time);
 	void RemoveTime(lcStep Start, lcStep Time);
@@ -207,6 +230,6 @@ public:
 
 protected:
 	QString mName;
-	bool mSimple = false;
+	bool mSimple = true;
 	lcCameraProjection mProjection = lcCameraProjection::Perspective;
 };
diff --git a/common/group.cpp b/common/group.cpp
index d0ad896c..5f52a21a 100644
--- a/common/group.cpp
+++ b/common/group.cpp
@@ -1,11 +1,15 @@
 #include "lc_global.h"
 #include <stdlib.h>
 #include "group.h"
+#include "lc_model.h"
 #include "lc_file.h"
 
+lcGroupId lcGroup::mNextId;
+
 lcGroup::lcGroup()
+    : mId(mNextId)
 {
-	mGroup = nullptr;
+	mNextId = static_cast<lcGroupId>(static_cast<uint32_t>(mNextId) + 1);
 }
 
 void lcGroup::FileLoad(lcFile* File)
@@ -58,3 +62,37 @@ void lcGroup::CreateName(const std::vector<std::unique_ptr<lcGroup>>& Groups)
 
 	mName = Prefix + QString::number(Max + 1);
 }
+
+lcGroupHistoryState lcGroup::GetHistoryState(const lcModel* Model) const
+{
+	lcGroupHistoryState State;
+	
+	State.Id = mId;
+	State.ParentIndex = ~0;
+	State.Name = mName;
+	
+	if (mGroup)
+	{
+		const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
+		
+		for (size_t GroupIndex = 0; GroupIndex < Groups.size(); GroupIndex++)
+		{
+			if (Groups[GroupIndex].get() == mGroup)
+			{
+				State.ParentIndex = GroupIndex;
+				break;
+			}
+		}
+	}
+	
+	return State;
+}
+
+void lcGroup::SetHistoryState(const lcGroupHistoryState& State, const lcModel* Model)
+{
+	const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
+	
+	mId = State.Id;
+	mName = State.Name;
+	mGroup = (State.ParentIndex < Groups.size()) ? Groups[State.ParentIndex].get() : nullptr;
+}
diff --git a/common/group.h b/common/group.h
index a39534f9..7eb6293d 100644
--- a/common/group.h
+++ b/common/group.h
@@ -2,6 +2,20 @@
 
 #define LC_MAX_GROUP_NAME 64
 
+enum class lcGroupId : uint32_t;
+
+struct lcGroupHistoryState
+{
+	lcGroupId Id;
+	uint32_t ParentIndex;
+	QString Name;
+	
+	bool operator==(const lcGroupHistoryState& Other) const
+	{
+		return Id == Other.Id && ParentIndex == Other.ParentIndex && Name == Other.Name;
+	}
+};
+
 class lcGroup
 {
 public:
@@ -11,11 +25,23 @@ public:
 	{
 		return mGroup ? mGroup->GetTopGroup() : this;
 	}
-
+	
+	lcGroupId GetId() const
+	{
+		return mId;
+	}
+	
 	void FileLoad(lcFile* File);
 	void CreateName(const std::vector<std::unique_ptr<lcGroup>>& Groups);
-
-	lcGroup* mGroup;
+	
+	lcGroupHistoryState GetHistoryState(const lcModel* Model) const;
+	void SetHistoryState(const lcGroupHistoryState& State, const lcModel* Model);
+	
+	lcGroup* mGroup = nullptr;
 	QString mName;
+	
+protected:
+	lcGroupId mId = static_cast<lcGroupId>(0);
+	
+	static lcGroupId mNextId;
 };
-
diff --git a/common/lc_math.h b/common/lc_math.h
index c2ef475f..48503c68 100644
--- a/common/lc_math.h
+++ b/common/lc_math.h
@@ -464,6 +464,11 @@ inline bool operator==(const lcMatrix33& a, const lcMatrix33& b)
 	return a.r[0] == b.r[0] && a.r[1] == b.r[1] && a.r[2] == b.r[2];
 }
 
+inline bool operator==(const lcMatrix44& a, const lcMatrix44& b)
+{
+	return a.r[0] == b.r[0] && a.r[1] == b.r[1] && a.r[2] == b.r[2] && a.r[3] == b.r[3];
+}
+
 #ifndef QT_NO_DEBUG
 
 inline QDebug operator<<(QDebug Debug, const lcVector2& v)
diff --git a/common/lc_model.cpp b/common/lc_model.cpp
index 4567f90b..85f932e7 100644
--- a/common/lc_model.cpp
+++ b/common/lc_model.cpp
@@ -1809,6 +1809,49 @@ void lcModel::RunSelectionAction(const lcModelActionSelection* ModelActionSelect
 		ModelActionSelection->LoadStartState(this);
 }
 
+template<typename StateType, typename ObjectType>
+void lcModel::LoadObjectHistoryState(const std::vector<StateType>& ObjectStates, std::vector<std::unique_ptr<ObjectType>>& Objects)
+{
+	std::vector<std::unique_ptr<ObjectType>> NewObjects;
+	
+	NewObjects.reserve(ObjectStates.size());
+	
+	for (const StateType& ObjectState : ObjectStates)
+	{
+		auto ObjectId = ObjectState.Id;
+		bool Found = false;
+		
+		for (auto ObjectIt = Objects.begin(); ObjectIt != Objects.end(); ++ObjectIt)
+		{
+			ObjectType* Object = ObjectIt->get();
+			
+			if (Object->GetId() == ObjectId)
+			{
+				NewObjects.emplace_back(std::move(*ObjectIt));
+				Objects.erase(ObjectIt);
+				Found = true;
+				break;
+			}
+		}
+		
+		if (!Found)
+			NewObjects.emplace_back(new ObjectType());
+	}
+	
+	Objects = std::move(NewObjects);
+	
+	for (size_t ObjectIndex = 0; ObjectIndex < Objects.size(); ObjectIndex++)
+		Objects[ObjectIndex]->SetHistoryState(ObjectStates[ObjectIndex], this);
+}
+
+void lcModel::LoadHistoryState(const lcModelHistoryState& HistoryState)
+{
+	LoadObjectHistoryState(HistoryState.Groups, mGroups);
+	LoadObjectHistoryState(HistoryState.Pieces, mPieces);
+	LoadObjectHistoryState(HistoryState.Cameras, mCameras);
+	LoadObjectHistoryState(HistoryState.Lights, mLights);
+}
+
 void lcModel::BeginObjectEditAction(lcModelActionObjectEditMode ModelActionObjectEditMode, const lcCamera* Camera)
 {
 	std::unique_ptr<lcModelActionObjectEdit> ModelActionObjectEdit = std::make_unique<lcModelActionObjectEdit>(ModelActionObjectEditMode);
@@ -1816,8 +1859,7 @@ void lcModel::BeginObjectEditAction(lcModelActionObjectEditMode ModelActionObjec
 	if (!ModelActionObjectEdit)
 		return;
 	
-	if (!ModelActionObjectEdit->SaveStartState(this, Camera))
-		return;
+	ModelActionObjectEdit->SaveStartState(this, Camera);
 
 	mActionSequence.emplace_back(std::move(ModelActionObjectEdit));
 }
@@ -1832,7 +1874,9 @@ void lcModel::EndObjectEditAction(std::vector<size_t>&& ObjectIndices, std::vect
 	if (!ModelActionObjectEdit)
 		return;
 	
-	if (!ModelActionObjectEdit->SaveEndState(this, std::move(ObjectIndices), std::move(GroupIndices)))
+	ModelActionObjectEdit->SaveEndState(this, std::move(ObjectIndices), std::move(GroupIndices));
+	
+	if (ModelActionObjectEdit->StateChanged())
 		mActionSequence.pop_back();
 }
 
@@ -4950,7 +4994,7 @@ void lcModel::InsertCameraToolClicked(const lcVector3& Position)
 	BeginActionSequence();
 	BeginObjectEditAction(lcModelActionObjectEditMode::CreateCamera, nullptr);
 	
-	lcCamera* Camera = new lcCamera(Position, GetSelectionOrModelCenter());
+	lcCamera* Camera = new lcCamera(false, Position, GetSelectionOrModelCenter());
 	
 	Camera->CreateName(mCameras);
 	mCameras.emplace_back(Camera);
diff --git a/common/lc_model.h b/common/lc_model.h
index e85fa68d..b9ab73d6 100644
--- a/common/lc_model.h
+++ b/common/lc_model.h
@@ -5,6 +5,7 @@
 
 enum class lcObjectPropertyId;
 enum class lcCameraProjection;
+struct lcModelHistoryState;
 class lcModelAction;
 class lcModelActionSelection;
 class lcModelActionObjectEdit;
@@ -229,7 +230,11 @@ public:
 	void ShowNextStep();
 	void InsertStep(lcStep Step);
 	void RemoveStep(lcStep Step);
-
+	
+	template<typename StateType, typename ObjectType>
+	void LoadObjectHistoryState(const std::vector<StateType>& ObjectStates, std::vector<std::unique_ptr<ObjectType>>& Objects);
+	void LoadHistoryState(const lcModelHistoryState& HistoryState);
+	
 	lcPiece* AddPiece(PieceInfo* Info, quint32 Section);
 	void AddPiece(std::unique_ptr<lcPiece> Piece, size_t PieceIndex);
 	void RemovePieces(const std::vector<size_t>& PieceIndices);
diff --git a/common/lc_modelaction.cpp b/common/lc_modelaction.cpp
index 48652481..23f27342 100644
--- a/common/lc_modelaction.cpp
+++ b/common/lc_modelaction.cpp
@@ -143,332 +143,60 @@ void lcModelActionSelection::LoadState(const lcModelActionSelectionState& State,
 }
 
 lcModelActionObjectEdit::lcModelActionObjectEdit(lcModelActionObjectEditMode Mode)
-	: mMode(Mode)
 {
 }
 
-
-bool lcModelActionObjectEdit::SaveHistoryBuffer(QByteArray& Buffer, const lcModel* Model)
+void lcModelActionObjectEdit::SaveState(lcModelHistoryState& State, const lcModel* Model)
 {
-	QDataStream Stream(&Buffer, QIODevice::WriteOnly);
-	
 	const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
+	
+	for (const std::unique_ptr<lcGroup>& Group : Groups)
+		State.Groups.emplace_back(Group->GetHistoryState(Model));
+	
 	const std::vector<std::unique_ptr<lcPiece>>& Pieces = Model->GetPieces();
+	
+	for (const std::unique_ptr<lcPiece>& Piece : Pieces)
+		State.Pieces.emplace_back(Piece->GetHistoryState(Model));
+	
 	const std::vector<std::unique_ptr<lcCamera>>& Cameras = Model->GetCameras();
+	
+	for (const std::unique_ptr<lcCamera>& Camera : Cameras)
+		State.Cameras.emplace_back(Camera->GetHistoryState(Model));
+	
 	const std::vector<std::unique_ptr<lcLight>>& Lights = Model->GetLights();
 	
-	uint64_t ObjectCount[4] = { Groups.size(), Pieces.size(), Cameras.size(), Lights.size() };
-	
-	if (Stream.writeRawData(reinterpret_cast<const char*>(ObjectCount), sizeof(ObjectCount)) != sizeof(ObjectCount))
-		return false;
-	
-	for (size_t GroupIndex : mGroupIndices)
-	{
-		const lcGroup* Group = Groups[GroupIndex].get();
-		uint64_t ParentIndex = UINT64_MAX;
-		
-		if (Group->mGroup)
-			for (ParentIndex = 0; ParentIndex < Groups.size(); ParentIndex++)
-				if (Group->mGroup == Groups[ParentIndex].get())
-					break;
-		
-		Stream << Group->mName;
-		Stream << ParentIndex;
-	}
-	
-	for (size_t PieceIndex : mPieceIndices)
-		if (!Pieces[PieceIndex]->SaveUndoData(Stream, Model))
-			return false;
-	
-	for (size_t CameraIndex : mCameraIndices)
-		if (!Cameras[CameraIndex]->SaveUndoData(Stream, Model))
-			return false;
-	
-	for (size_t LightIndex : mLightIndices)
-		if (!Lights[LightIndex]->SaveUndoData(Stream, Model))
-			return false;
-	
-	return true;
+	for (const std::unique_ptr<lcLight>& Light : Lights)
+		State.Lights.emplace_back(Light->GetHistoryState(Model));
 }
 
-bool lcModelActionObjectEdit::LoadHistoryBuffer(const QByteArray& Buffer, lcModel* Model, bool CreateObjects) const
+void lcModelActionObjectEdit::LoadState(const lcModelHistoryState& State, lcModel* Model)
 {
-	QDataStream Stream(const_cast<QByteArray*>(&Buffer), QIODevice::ReadOnly);
-	
-	const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
-	const std::vector<std::unique_ptr<lcPiece>>& Pieces = Model->GetPieces();
-	const std::vector<std::unique_ptr<lcCamera>>& Cameras = Model->GetCameras();
-	const std::vector<std::unique_ptr<lcLight>>& Lights = Model->GetLights();
-	
-	uint64_t ObjectCount[4];
-	
-	if (Stream.readRawData(reinterpret_cast<char*>(ObjectCount), sizeof(ObjectCount)) != sizeof(ObjectCount))
-		return false;
-	
-	if (CreateObjects)
-	{
-		ObjectCount[0] -= mGroupIndices.size();
-		ObjectCount[1] -= mPieceIndices.size();
-		ObjectCount[2] -= mCameraIndices.size();
-		ObjectCount[3] -= mLightIndices.size();
-	}
-	
-	if (ObjectCount[0] != Groups.size() || ObjectCount[1] != Pieces.size() || ObjectCount[2] != Cameras.size() || ObjectCount[3] != Lights.size())
-		return false;
-	
-	if (CreateObjects)
-	{
-		for (size_t GroupIndex : mGroupIndices)
-		{
-			std::unique_ptr<lcGroup> Group(new lcGroup());
-			QString Name;
-			uint64_t ParentIndex;
-			
-			Stream >> Name;
-			Stream >> ParentIndex;
-			
-			Group->mName = Name;
-			Group->mGroup = ParentIndex < Groups.size() ? Groups[ParentIndex].get() : nullptr;
-			
-			Model->AddGroup(std::move(Group), GroupIndex);			
-		}
-		
-		for (size_t PieceIndex : mPieceIndices)
-		{
-			if (PieceIndex > Pieces.size())
-				return false;
-			
-			std::unique_ptr<lcPiece> Piece(new lcPiece(nullptr));
-			
-			if (!Piece->LoadUndoData(Stream, Model))
-				return false;
-			
-			Model->AddPiece(std::move(Piece), PieceIndex);
-		}
-		
-		for (size_t CameraIndex : mCameraIndices)
-		{
-			if (CameraIndex > Cameras.size())
-				return false;
-			
-			std::unique_ptr<lcCamera> Camera(new lcCamera(false));
-			
-			if (!Camera->LoadUndoData(Stream, Model))
-				return false;
-			
-			Model->AddCamera(std::move(Camera), CameraIndex);
-		}
-		
-		for (size_t LightIndex : mLightIndices)
-		{
-			if (LightIndex > Lights.size())
-				return false;
-			
-			std::unique_ptr<lcLight> Light(new lcLight(lcVector3(0.0f, 0.0f, 0.0f), lcLightType::Point));
-			
-			if (!Light->LoadUndoData(Stream, Model))
-				return false;
-			
-			Model->AddLight(std::move(Light), LightIndex);
-		}
-	}
-	else
-	{
-		for (size_t GroupIndex : mGroupIndices)
-		{
-			lcGroup* Group = Groups[GroupIndex].get();
-			QString Name;
-			uint64_t ParentIndex;
-			
-			Stream >> Name;
-			Stream >> ParentIndex;
-			
-			Group->mName = Name;
-			Group->mGroup = ParentIndex < Groups.size() ? Groups[ParentIndex].get() : nullptr;
-		}
-		
-		for (size_t PieceIndex : mPieceIndices)
-		{
-			if (PieceIndex >= Pieces.size())
-				return false;
-			
-			const std::unique_ptr<lcPiece>& Piece = Pieces[PieceIndex];
-			
-			if (!Piece->LoadUndoData(Stream, Model))
-				return false;
-		}
-		
-		for (size_t CameraIndex : mCameraIndices)
-		{
-			if (CameraIndex >= Cameras.size())
-				return false;
-			
-			const std::unique_ptr<lcCamera>& Camera = Cameras[CameraIndex];
-			
-			if (!Camera->LoadUndoData(Stream, Model))
-				return false;
-		}
-		
-		for (size_t LightIndex : mLightIndices)
-		{
-			if (LightIndex >= Lights.size())
-				return false;
-			
-			const std::unique_ptr<lcLight>& Light = Lights[LightIndex];
-			
-			if (!Light->LoadUndoData(Stream, Model))
-				return false;
-		}
-	}
-	
-	return true;
+	Model->LoadHistoryState(State);
 }
 
-bool lcModelActionObjectEdit::SaveStartState(const lcModel* Model, const lcCamera* Camera)
+void lcModelActionObjectEdit::SaveStartState(const lcModel* Model, const lcCamera* Camera)
 {
-	const std::vector<std::unique_ptr<lcPiece>>& Pieces = Model->GetPieces();
-	const std::vector<std::unique_ptr<lcCamera>>& Cameras = Model->GetCameras();
-	const std::vector<std::unique_ptr<lcLight>>& Lights = Model->GetLights();
-	
-	switch (mMode)
-	{
-	case lcModelActionObjectEditMode::EditAllObjects:
-		mPieceIndices.resize(Pieces.size());
-		std::iota(mPieceIndices.begin(), mPieceIndices.end(), 0);
-		
-		mCameraIndices.resize(Cameras.size());
-		std::iota(mCameraIndices.begin(), mCameraIndices.end(), 0);
-		
-		mLightIndices.resize(Lights.size());
-		std::iota(mLightIndices.begin(), mLightIndices.end(), 0);
-		break;
-		
-	case lcModelActionObjectEditMode::EditAllPieces:
-		mPieceIndices.resize(Pieces.size());
-		std::iota(mPieceIndices.begin(), mPieceIndices.end(), 0);
-		break;
-		
-	case lcModelActionObjectEditMode::EditSelectedObjects:
-		for (size_t PieceIndex = 0; PieceIndex < Pieces.size(); PieceIndex++)
-			if (Pieces[PieceIndex]->IsSelected())
-				mPieceIndices.push_back(PieceIndex);
-		
-		for (size_t CameraIndex = 0; CameraIndex < Cameras.size(); CameraIndex++)
-			if (Cameras[CameraIndex]->IsSelected())
-				mCameraIndices.push_back(CameraIndex);
-		
-		for (size_t LightIndex = 0; LightIndex < Lights.size(); LightIndex++)
-			if (Lights[LightIndex]->IsSelected())
-				mLightIndices.push_back(LightIndex);
-		break;
-		
-	case lcModelActionObjectEditMode::EditSelectedPieces:
-		for (size_t PieceIndex = 0; PieceIndex < Pieces.size(); PieceIndex++)
-			if (Pieces[PieceIndex]->IsSelected())
-				mPieceIndices.push_back(PieceIndex);
-		break;
-		
-	case lcModelActionObjectEditMode::EditUnselectedPieces:
-		for (size_t PieceIndex = 0; PieceIndex < Pieces.size(); PieceIndex++)
-			if (!Pieces[PieceIndex]->IsSelected())
-				mPieceIndices.push_back(PieceIndex);
-		break;
-		
-	case lcModelActionObjectEditMode::EditCamera:
-		for (size_t CameraIndex = 0; CameraIndex < Cameras.size(); CameraIndex++)
-		{
-			if (Cameras[CameraIndex].get() == Camera)
-			{
-				mCameraIndices.push_back(CameraIndex);
-				break;
-			}
-		}
-		break;
-	
-	case lcModelActionObjectEditMode::CreatePieces:
-	case lcModelActionObjectEditMode::CreateCamera:
-	case lcModelActionObjectEditMode::CreateLight:
-		break;
-	};
-	
-	return SaveHistoryBuffer(mStartBuffer, Model);
+	SaveState(mStartState, Model);
 }
 
-bool lcModelActionObjectEdit::SaveEndState(const lcModel* Model, std::vector<size_t>&& ObjectIndices, std::vector<size_t>&& GroupIndices)
+void lcModelActionObjectEdit::SaveEndState(const lcModel* Model, std::vector<size_t>&& ObjectIndices, std::vector<size_t>&& GroupIndices)
 {
-	switch (mMode)
-	{
-	case lcModelActionObjectEditMode::EditAllObjects:
-	case lcModelActionObjectEditMode::EditAllPieces:
-	case lcModelActionObjectEditMode::EditSelectedObjects:
-	case lcModelActionObjectEditMode::EditSelectedPieces:
-	case lcModelActionObjectEditMode::EditUnselectedPieces:
-	case lcModelActionObjectEditMode::EditCamera:
-		break;
-	
-	case lcModelActionObjectEditMode::CreatePieces:
-		mPieceIndices = std::move(ObjectIndices);
-		mGroupIndices = std::move(GroupIndices);
-		break;
-		
-	case lcModelActionObjectEditMode::CreateCamera:
-		mCameraIndices = std::move(ObjectIndices);
-		break;
-		
-	case lcModelActionObjectEditMode::CreateLight:
-		mLightIndices = std::move(ObjectIndices);
-		break;
-	};
-	
-	return SaveHistoryBuffer(mEndBuffer, Model);	
+	SaveState(mEndState, Model);
 }
 
 void lcModelActionObjectEdit::LoadStartState(lcModel* Model) const
 {
-	switch (mMode)
-	{
-	case lcModelActionObjectEditMode::EditAllObjects:
-	case lcModelActionObjectEditMode::EditAllPieces:
-	case lcModelActionObjectEditMode::EditSelectedObjects:
-	case lcModelActionObjectEditMode::EditSelectedPieces:
-	case lcModelActionObjectEditMode::EditUnselectedPieces:
-	case lcModelActionObjectEditMode::EditCamera:
-		LoadHistoryBuffer(mStartBuffer, Model, false);
-		break;
-	
-	case lcModelActionObjectEditMode::CreatePieces:
-		Model->RemovePieces(mPieceIndices);
-		break;
-		
-	case lcModelActionObjectEditMode::CreateCamera:
-   		Model->RemoveCameras(mCameraIndices);
-		break;
-		
-	case lcModelActionObjectEditMode::CreateLight:
-		Model->RemoveLights(mLightIndices);
-		break;
-	};
+	LoadState(mStartState, Model);
 }
 
 void lcModelActionObjectEdit::LoadEndState(lcModel* Model) const
 {
-	switch (mMode)
-	{
-	case lcModelActionObjectEditMode::EditAllObjects:
-	case lcModelActionObjectEditMode::EditAllPieces:
-	case lcModelActionObjectEditMode::EditSelectedObjects:
-	case lcModelActionObjectEditMode::EditSelectedPieces:
-	case lcModelActionObjectEditMode::EditUnselectedPieces:
-	case lcModelActionObjectEditMode::EditCamera:
-		LoadHistoryBuffer(mEndBuffer, Model, false);
-		break;
-	
-	case lcModelActionObjectEditMode::CreatePieces:
-	case lcModelActionObjectEditMode::CreateCamera:
-	case lcModelActionObjectEditMode::CreateLight:
-		LoadHistoryBuffer(mEndBuffer, Model, true);
-		break;
-	};
+	LoadState(mEndState, Model);
+}
+
+bool lcModelActionObjectEdit::StateChanged() const
+{
+	return mStartState != mEndState;
 }
 
 lcModelActionGroupPieces::lcModelActionGroupPieces(lcModelActionGroupPiecesMode Mode, const QString& GroupName)
diff --git a/common/lc_modelaction.h b/common/lc_modelaction.h
index 755e566d..ed74692b 100644
--- a/common/lc_modelaction.h
+++ b/common/lc_modelaction.h
@@ -60,34 +60,43 @@ enum class lcModelActionObjectEditMode
 	CreateLight
 };
 
+struct lcGroupHistoryState;
+struct lcPieceHistoryState;
+struct lcCameraHistoryState;
+struct lcLightHistoryState;
+
+struct lcModelHistoryState
+{
+	std::vector<lcGroupHistoryState> Groups;
+	std::vector<lcPieceHistoryState> Pieces;
+	std::vector<lcCameraHistoryState> Cameras;
+	std::vector<lcLightHistoryState> Lights;
+	
+	bool operator!=(const lcModelHistoryState& Other) const
+	{
+		return Groups != Other.Groups || Pieces != Other.Pieces || Cameras != Other.Cameras || Lights != Other.Lights;
+	}
+};
+
 class lcModelActionObjectEdit: public lcModelAction
 {
 public:
 	lcModelActionObjectEdit(lcModelActionObjectEditMode Mode);
 	virtual ~lcModelActionObjectEdit() = default;
 	
-	bool SaveStartState(const lcModel* Model, const lcCamera* Camera);
-	bool SaveEndState(const lcModel* Model, std::vector<size_t>&& ObjectIndices, std::vector<size_t>&& GroupIndices);
+	void SaveStartState(const lcModel* Model, const lcCamera* Camera);
+	void SaveEndState(const lcModel* Model, std::vector<size_t>&& ObjectIndices, std::vector<size_t>&& GroupIndices);
 	void LoadStartState(lcModel* Model) const;
 	void LoadEndState(lcModel* Model) const;
-
-	lcModelActionObjectEditMode GetMode() const
-	{
-		return mMode;
-	}
+	
+	bool StateChanged() const;
 
 protected:
-	bool SaveHistoryBuffer(QByteArray& Buffer, const lcModel* Model);
-	bool LoadHistoryBuffer(const QByteArray& Buffer, lcModel* Model, bool CreateObjects) const;
+	static void SaveState(lcModelHistoryState& State, const lcModel* Model);
+	static void LoadState(const lcModelHistoryState& State, lcModel* Model);
 	
-	std::vector<size_t> mGroupIndices;
-	std::vector<size_t> mPieceIndices;
-	std::vector<size_t> mCameraIndices;
-	std::vector<size_t> mLightIndices;
-	
-	lcModelActionObjectEditMode mMode;
-	QByteArray mStartBuffer;
-	QByteArray mEndBuffer;
+	lcModelHistoryState mStartState;
+	lcModelHistoryState mEndState;
 };
 
 enum class lcModelActionGroupPiecesMode
diff --git a/common/lc_objectproperty.cpp b/common/lc_objectproperty.cpp
index 25ce5987..50958494 100644
--- a/common/lc_objectproperty.cpp
+++ b/common/lc_objectproperty.cpp
@@ -10,9 +10,7 @@
 	template bool lcObjectProperty<T>::HasKeyFrame(lcStep Time) const; \
 	template bool lcObjectProperty<T>::SetKeyFrame(lcStep Time, bool KeyFrame); \
 	template void lcObjectProperty<T>::Save(QTextStream& Stream, const char* ObjectName, const char* VariableName, bool SaveEmpty) const; \
-	template bool lcObjectProperty<T>::Load(QTextStream& Stream, const QString& Token, const char* VariableName); \
-    template bool lcObjectProperty<T>::SaveUndoData(QDataStream& Stream) const; \
-    template bool lcObjectProperty<T>::LoadUndoData(QDataStream& Stream);
+	template bool lcObjectProperty<T>::Load(QTextStream& Stream, const QString& Token, const char* VariableName);
 
 LC_OBJECT_PROPERTY(float)
 LC_OBJECT_PROPERTY(int)
@@ -314,42 +312,3 @@ bool lcObjectProperty<T>::Load(QTextStream& Stream, const QString& Token, const
 
 	return false;
 }
-
-template<typename T>
-bool lcObjectProperty<T>::SaveUndoData(QDataStream& Stream) const
-{
-	size_t KeyCount = mKeys.size();
-	qint64 DataSize = KeyCount * sizeof(lcObjectPropertyKey<T>);
-	
-	if (Stream.writeRawData(reinterpret_cast<const char*>(&mValue), sizeof(mValue)) != sizeof(mValue))
-		return false;
-
-	if (Stream.writeRawData(reinterpret_cast<const char*>(&KeyCount), sizeof(KeyCount)) != sizeof(KeyCount))
-		return false;
-
-	if (Stream.writeRawData(reinterpret_cast<const char*>(mKeys.data()), DataSize) != DataSize)
-		return false;
-
-	return true;
-}
-
-template<typename T>
-bool lcObjectProperty<T>::LoadUndoData(QDataStream& Stream)
-{
-	if (Stream.readRawData(reinterpret_cast<char*>(&mValue), sizeof(mValue)) != sizeof(mValue))
-		return false;
-	
-	size_t KeyCount;
-	
-	if (Stream.readRawData(reinterpret_cast<char*>(&KeyCount), sizeof(KeyCount)) != sizeof(KeyCount))
-		return false;
-	
-	mKeys.resize(KeyCount);
-	
-	qsizetype DataSize = KeyCount * sizeof(lcObjectPropertyKey<T>);
-	
-	if (Stream.readRawData(reinterpret_cast<char*>(mKeys.data()), DataSize) != DataSize)
-		return false;
-	
-	return true;	
-}
diff --git a/common/lc_objectproperty.h b/common/lc_objectproperty.h
index d2dde646..071232f2 100644
--- a/common/lc_objectproperty.h
+++ b/common/lc_objectproperty.h
@@ -67,11 +67,13 @@ template<typename T>
 class lcObjectProperty
 {
 public:
+	lcObjectProperty() = default;
+	
 	explicit lcObjectProperty(const T& DefaultValue)
 		: mValue(DefaultValue)
 	{
 	}
-
+	
 	operator const T& () const
 	{
 		return mValue;
@@ -96,8 +98,6 @@ public:
 
 	void Save(QTextStream& Stream, const char* ObjectName, const char* VariableName, bool SaveEmpty) const;
 	bool Load(QTextStream& Stream, const QString& Token, const char* VariableName);
-	bool SaveUndoData(QDataStream& Stream) const;
-	bool LoadUndoData(QDataStream& Stream);
 
 protected:
 	T mValue;
diff --git a/common/light.cpp b/common/light.cpp
index 34fb2efd..4ab16282 100644
--- a/common/light.cpp
+++ b/common/light.cpp
@@ -19,6 +19,11 @@
 static const std::array<QLatin1String, static_cast<int>(lcLightType::Count)> gLightTypes = { QLatin1String("POINT"), QLatin1String("SPOT"), QLatin1String("DIRECTIONAL"), QLatin1String("AREA") };
 static const std::array<QLatin1String, static_cast<int>(lcLightAreaShape::Count)> gLightAreaShapes = { QLatin1String("RECTANGLE"), QLatin1String("SQUARE"), QLatin1String("DISK"), QLatin1String("ELLIPSE") };
 
+lcLight::lcLight()
+    : lcObject(lcObjectType::Light)
+{
+}
+
 lcLight::lcLight(const lcVector3& Position, lcLightType LightType)
 	: lcObject(lcObjectType::Light), mLightType(LightType)
 {
@@ -1529,49 +1534,58 @@ void lcLight::RemoveKeyFrames()
 	mPOVRayFadePower.RemoveAllKeys();
 }
 
-bool lcLight::SaveUndoData(QDataStream& Stream, const lcModel* Model) const
+lcLightHistoryState lcLight::GetHistoryState(const lcModel* Model) const
 {
-	static_assert(sizeof(lcLight) == 704);
-	Q_UNUSED(Model);
+	lcLightHistoryState State;
 	
-	Stream << mName;
-	Stream << mLightType;
-	Stream << mCastShadow;
-	Stream << mAreaShape;
-	Stream << mHidden;
+	State.Id = mId;
+	State.Hidden = mHidden;
+	State.Name = mName;
+	State.LightType = mLightType;
+	State.CastShadow = mCastShadow;
+	State.Position = mPosition;
+	State.Rotation = mRotation;
+	State.Color = mColor;
+	State.BlenderPower = mBlenderPower;
+	State.BlenderRadius = mBlenderRadius;
+	State.BlenderAngle = mBlenderAngle;
+	State.POVRayPower = mPOVRayPower;
+	State.POVRayFadeDistance = mPOVRayFadeDistance;
+	State.POVRayFadePower = mPOVRayFadePower;
+	State.SpotConeAngle = mSpotConeAngle;
+	State.SpotPenumbraAngle = mSpotPenumbraAngle;
+	State.POVRaySpotTightness = mPOVRaySpotTightness;
+	State.AreaShape = mAreaShape;
+	State.AreaSizeX = mAreaSizeX;
+	State.AreaSizeY = mAreaSizeY;
+	State.POVRayAreaGridX = mPOVRayAreaGridX;
+	State.POVRayAreaGridY = mPOVRayAreaGridY;
 
-	return mPosition.SaveUndoData(Stream) && mRotation.SaveUndoData(Stream) && mColor.SaveUndoData(Stream) &&
-           mSpotConeAngle.SaveUndoData(Stream) && mSpotPenumbraAngle.SaveUndoData(Stream) && mPOVRaySpotTightness.SaveUndoData(Stream) &&
-	       mPOVRayAreaGridX.SaveUndoData(Stream) && mPOVRayAreaGridY.SaveUndoData(Stream) && mBlenderRadius.SaveUndoData(Stream) &&
-	       mBlenderAngle.SaveUndoData(Stream) && mAreaSizeX.SaveUndoData(Stream) && mAreaSizeY.SaveUndoData(Stream) &&
-	       mBlenderPower.SaveUndoData(Stream) && mPOVRayPower.SaveUndoData(Stream) && mPOVRayFadeDistance.SaveUndoData(Stream) &&
-	       mPOVRayFadePower.SaveUndoData(Stream);
+	return State;
 }
 
-bool lcLight::LoadUndoData(QDataStream& Stream, const lcModel* Model)
+void lcLight::SetHistoryState(const lcLightHistoryState& State, const lcModel* Model)
 {
-	Q_UNUSED(Model);
-	
-	Stream >> mName;
-	Stream >> mLightType;
-	Stream >> mCastShadow;
-	Stream >> mAreaShape;
-	Stream >> mHidden;
-
-	return mPosition.LoadUndoData(Stream) &&
-        mRotation.LoadUndoData(Stream) &&
-        mColor.LoadUndoData(Stream) &&
-        mSpotConeAngle.LoadUndoData(Stream) &&
-        mSpotPenumbraAngle.LoadUndoData(Stream) &&
-        mPOVRaySpotTightness.LoadUndoData(Stream) &&
-        mPOVRayAreaGridX.LoadUndoData(Stream) &&
-        mPOVRayAreaGridY.LoadUndoData(Stream) &&
-        mBlenderRadius.LoadUndoData(Stream) &&
-        mBlenderAngle.LoadUndoData(Stream) &&
-        mAreaSizeX.LoadUndoData(Stream) &&
-        mAreaSizeY.LoadUndoData(Stream) &&
-        mBlenderPower.LoadUndoData(Stream) &&
-        mPOVRayPower.LoadUndoData(Stream) &&
-        mPOVRayFadeDistance.LoadUndoData(Stream) &&
-        mPOVRayFadePower.LoadUndoData(Stream);
+	mId = State.Id;
+	mHidden = State.Hidden;
+	mName = State.Name;
+	mLightType = State.LightType;
+	mCastShadow = State.CastShadow;
+	mPosition = State.Position;
+	mRotation = State.Rotation;
+	mColor = State.Color;
+	mBlenderPower = State.BlenderPower;
+	mBlenderRadius = State.BlenderRadius;
+	mBlenderAngle = State.BlenderAngle;
+	mPOVRayPower = State.POVRayPower;
+	mPOVRayFadeDistance = State.POVRayFadeDistance;
+	mPOVRayFadePower = State.POVRayFadePower;
+	mSpotConeAngle = State.SpotConeAngle;
+	mSpotPenumbraAngle = State.SpotPenumbraAngle;
+	mPOVRaySpotTightness = State.POVRaySpotTightness;
+	mAreaShape = State.AreaShape;
+	mAreaSizeX = State.AreaSizeX;
+	mAreaSizeY = State.AreaSizeY;
+	mPOVRayAreaGridX = State.POVRayAreaGridX;
+	mPOVRayAreaGridY = State.POVRayAreaGridY;
 }
diff --git a/common/light.h b/common/light.h
index b766fb12..3344e31f 100644
--- a/common/light.h
+++ b/common/light.h
@@ -28,9 +28,47 @@ enum class lcLightAreaShape
 	Count
 };
 
+struct lcLightHistoryState
+{
+	lcObjectId Id;
+	bool Hidden;
+	QString Name;
+	lcLightType LightType;
+	bool CastShadow;
+	lcObjectProperty<lcVector3> Position;
+	lcObjectProperty<lcMatrix33> Rotation;
+	lcObjectProperty<lcVector3> Color;
+	lcObjectProperty<float> BlenderPower;
+	lcObjectProperty<float> BlenderRadius;
+	lcObjectProperty<float> BlenderAngle;
+	lcObjectProperty<float> POVRayPower;
+	lcObjectProperty<float> POVRayFadeDistance;
+	lcObjectProperty<float> POVRayFadePower;
+	lcObjectProperty<float> SpotConeAngle;
+	lcObjectProperty<float> SpotPenumbraAngle;
+	lcObjectProperty<float> POVRaySpotTightness;
+	lcLightAreaShape AreaShape;
+	lcObjectProperty<float> AreaSizeX;
+	lcObjectProperty<float> AreaSizeY;
+	lcObjectProperty<int> POVRayAreaGridX;
+	lcObjectProperty<int> POVRayAreaGridY;
+	
+	bool operator==(const lcLightHistoryState& Other) const
+	{
+		return Id == Other.Id && Hidden == Other.Hidden && Name == Other.Name && LightType == Other.LightType &&
+            CastShadow == Other.CastShadow && Position == Other.Position && Rotation == Other.Rotation && Color == Other.Color &&
+            BlenderPower == Other.BlenderPower && BlenderRadius == Other.BlenderRadius && BlenderAngle == Other.BlenderAngle &&
+            POVRayPower == Other.POVRayPower && POVRayFadeDistance == Other.POVRayFadeDistance && POVRayFadePower == Other.POVRayFadePower &&
+            SpotConeAngle == Other.SpotConeAngle && SpotPenumbraAngle == Other.SpotPenumbraAngle &&
+            POVRaySpotTightness == Other.POVRaySpotTightness && AreaShape == Other.AreaShape && AreaSizeX == Other.AreaSizeX &&
+            AreaSizeY == Other.AreaSizeY && POVRayAreaGridX == Other.POVRayAreaGridX && POVRayAreaGridY == Other.POVRayAreaGridY;
+	}
+};
+
 class lcLight : public lcObject
 {
 public:
+	lcLight();
 	lcLight(const lcVector3& Position, lcLightType LightType);
 	virtual ~lcLight() = default;
 
@@ -161,8 +199,8 @@ public:
 	bool HasKeyFrame(lcObjectPropertyId PropertyId, lcStep Time) const override;
 	bool SetKeyFrame(lcObjectPropertyId PropertyId, lcStep Time, bool KeyFrame) override;
 	void RemoveKeyFrames() override;
-	bool SaveUndoData(QDataStream& Stream, const lcModel* Model) const override;
-	bool LoadUndoData(QDataStream& Stream, const lcModel* Model) override;
+	lcLightHistoryState GetHistoryState(const lcModel* Model) const;
+	void SetHistoryState(const lcLightHistoryState& State, const lcModel* Model);
 
 	void InsertTime(lcStep Start, lcStep Time);
 	void RemoveTime(lcStep Start, lcStep Time);
diff --git a/common/object.cpp b/common/object.cpp
index e3f8fa11..ff818bc7 100644
--- a/common/object.cpp
+++ b/common/object.cpp
@@ -1,9 +1,12 @@
 #include "lc_global.h"
 #include "object.h"
 
+lcObjectId lcObject::mNextId;
+
 lcObject::lcObject(lcObjectType ObjectType)
-	: mObjectType(ObjectType)
+    : mObjectType(ObjectType), mId(mNextId)
 {
+	mNextId = static_cast<lcObjectId>(static_cast<uint32_t>(mNextId) + 1);
 }
 
 lcObject::~lcObject()
diff --git a/common/object.h b/common/object.h
index 83d04bf5..7a30339e 100644
--- a/common/object.h
+++ b/common/object.h
@@ -10,6 +10,8 @@ enum class lcObjectType
 	Light
 };
 
+enum class lcObjectId : uint32_t;
+
 struct lcObjectSection
 {
 	lcObject* Object = nullptr;
@@ -89,6 +91,11 @@ public:
 		return mObjectType;
 	}
 	
+	lcObjectId GetId() const
+	{
+		return mId;
+	}
+	
 	bool IsSelected() const
 	{
 		return mSelected;
@@ -139,8 +146,6 @@ public:
 	virtual bool HasKeyFrame(lcObjectPropertyId PropertyId, lcStep Time) const = 0;
 	virtual bool SetKeyFrame(lcObjectPropertyId PropertyId, lcStep Time, bool KeyFrame) = 0;
 	virtual void RemoveKeyFrames() = 0;
-	virtual bool SaveUndoData(QDataStream& Stream, const lcModel* Model) const = 0;
-	virtual bool LoadUndoData(QDataStream& Stream, const lcModel* Model) = 0;
 	virtual QString GetName() const = 0;
 	static QString GetCheckpointString(lcObjectPropertyId PropertyId);
 
@@ -151,4 +156,7 @@ protected:
 	bool mHidden = false;
 	bool mSelected = false;
 	quint32 mFocusedSection = LC_OBJECT_SECTION_INVALID;
+	lcObjectId mId = static_cast<lcObjectId>(0);
+	
+	static lcObjectId mNextId;
 };
diff --git a/common/piece.cpp b/common/piece.cpp
index e598c23d..6bed4239 100644
--- a/common/piece.cpp
+++ b/common/piece.cpp
@@ -20,15 +20,17 @@
 
 constexpr float LC_PIECE_CONTROL_POINT_SIZE = 10.0f;
 
+lcPiece::lcPiece()
+    : lcObject(lcObjectType::Piece)
+{
+}
+
 lcPiece::lcPiece(PieceInfo* Info)
 	: lcObject(lcObjectType::Piece)
 {
 	SetPieceInfo(Info, QString(), true, true);
 	mColorIndex = gDefaultColor;
 	mColorCode = 16;
-	mStepShow = 1;
-	mStepHide = LC_STEP_MAX;
-	mGroup = nullptr;
 	mPivotMatrix = lcMatrix44Identity();
 }
 
@@ -935,89 +937,68 @@ void lcPiece::RemoveKeyFrames()
 	mRotation.RemoveAllKeys();
 }
 
-bool lcPiece::SaveUndoData(QDataStream& Stream, const lcModel* Model) const
+lcPieceHistoryState lcPiece::GetHistoryState(const lcModel* Model) const
 {
-	static_assert(sizeof(lcPiece) == 384);
+	lcPieceHistoryState State;
 	
-	Stream << mFileLine;
-	Stream << mID;
+	State.Id = mId;
+	State.Hidden = mHidden;
+	State.FileLine = mFileLine;
+	State.PieceId = mID;
+	State.GroupIndex = ~0;
+	State.ColorIndex = mColorIndex;
+	State.ColorCode = mColorCode;
+	State.StepShow = mStepShow;
+	State.StepHide = mStepHide;
+	State.PivotMatrix = mPivotMatrix;
+	State.PivotPointValid = mPivotPointValid;
+	State.ControlPoints = mControlPoints;
+	State.Position = mPosition;
+	State.Rotation = mRotation;
 	
 	const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
-	uint64_t ParentIndex = UINT64_MAX;
 	
 	if (mGroup)
-		for (ParentIndex = 0; ParentIndex < Groups.size(); ParentIndex++)
-			if (mGroup == Groups[ParentIndex].get())
+	{
+		for (size_t GroupIndex = 0; GroupIndex < Groups.size(); GroupIndex++)
+		{
+			if (mGroup == Groups[GroupIndex].get())
+			{
+				State.GroupIndex = GroupIndex;
 				break;
+			}
+		}
+	}
 	
-	Stream << ParentIndex;
-	Stream << mColorIndex;
-	Stream << mColorCode;
-
-	Stream << mStepShow;
-	Stream << mStepHide;
-
-	Stream << mPivotMatrix;
-	Stream << mPivotPointValid;
-
-	Stream << mHidden;
-	
-	size_t ControlPointCount = mControlPoints.size();
-	qint64 DataSize = ControlPointCount * sizeof(lcPieceControlPoint);
-	
-	if (Stream.writeRawData(reinterpret_cast<const char*>(&ControlPointCount), sizeof(ControlPointCount)) != sizeof(ControlPointCount))
-		return false;
-	
-	if (Stream.writeRawData(reinterpret_cast<const char*>(mControlPoints.data()), DataSize) != DataSize)
-		return false;
-	
-	return mPosition.SaveUndoData(Stream) && mRotation.SaveUndoData(Stream);	
+	return State;
 }
 
-bool lcPiece::LoadUndoData(QDataStream& Stream, const lcModel* Model)
+void lcPiece::SetHistoryState(const lcPieceHistoryState& State, const lcModel* Model)
 {
-	Stream >> mFileLine;
-	Stream >> mID;
+	const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
+	
+	mId = State.Id;
+	mHidden = State.Hidden;
+	mFileLine = State.FileLine;
+	mID = State.PieceId;
+	mGroup = (State.GroupIndex < Groups.size()) ? Groups[State.GroupIndex].get() : nullptr;;
+	mColorIndex = State.ColorIndex;
+	mColorCode = State.ColorCode;
+	mStepShow = State.StepShow;
+	mStepHide = State.StepHide;
+	mPivotMatrix = State.PivotMatrix;
+	mPivotPointValid = State.PivotPointValid;
+	mControlPoints = State.ControlPoints;
+	mPosition = State.Position;
+	mRotation = State.Rotation;
 	
 	PieceInfo* Info = lcGetPiecesLibrary()->FindPiece(mID.toLatin1(), nullptr, true, false);
 	
 	SetPieceInfo(Info, mID, true, false);
 	
-	const std::vector<std::unique_ptr<lcGroup>>& Groups = Model->GetGroups();
-	uint64_t ParentIndex;
-	
-	Stream >> ParentIndex;
-	
-	mGroup = ParentIndex < Groups.size() ? Groups[ParentIndex].get() : nullptr;
-	
-	Stream >> mColorIndex;
-	Stream >> mColorCode;
-
-	Stream >> mStepShow;
-	Stream >> mStepHide;
-
-	Stream >> mPivotMatrix;
-	Stream >> mPivotPointValid;
-
-	Stream >> mHidden;
-	
-	size_t ControlPointCount;
-	
-	if (Stream.readRawData(reinterpret_cast<char*>(&ControlPointCount), sizeof(ControlPointCount)) != sizeof(ControlPointCount))
-		return false;
-	
-	mControlPoints.resize(ControlPointCount);
-	
-	qsizetype DataSize = ControlPointCount * sizeof(lcPieceControlPoint);
-	
-	if (Stream.readRawData(reinterpret_cast<char*>(mControlPoints.data()), DataSize) != DataSize)
-		return false;
-	
 	UpdateMesh();
 	
-//	std::vector<bool> mTrainTrackConnections;
-
-	return mPosition.LoadUndoData(Stream) && mRotation.LoadUndoData(Stream);
+	//	std::vector<bool> mTrainTrackConnections;
 }
 
 void lcPiece::AddMainModelRenderMeshes(lcScene* Scene, bool Highlight, bool Fade) const
diff --git a/common/piece.h b/common/piece.h
index 9cb6309a..db4f2d30 100644
--- a/common/piece.h
+++ b/common/piece.h
@@ -21,11 +21,44 @@ struct lcPieceControlPoint
 {
 	lcMatrix44 Transform;
 	float Scale;
+	
+	bool operator==(const lcPieceControlPoint& Other) const
+	{
+		return Transform == Other.Transform && Scale == Other.Scale;
+	}
+};
+
+struct lcPieceHistoryState
+{
+	lcObjectId Id;
+	bool Hidden;
+	int FileLine;
+	QString PieceId;
+	uint32_t GroupIndex;
+	int ColorIndex;
+	quint32 ColorCode;
+	lcStep StepShow;
+	lcStep StepHide;
+	lcMatrix44 PivotMatrix;
+	bool PivotPointValid;
+	std::vector<lcPieceControlPoint> ControlPoints;
+	lcObjectProperty<lcVector3> Position;
+	lcObjectProperty<lcMatrix33> Rotation;
+	
+	bool operator==(const lcPieceHistoryState& Other) const
+	{
+		return Id == Other.Id && Hidden == Other.Hidden && FileLine == Other.FileLine && PieceId == Other.PieceId &&
+            GroupIndex == Other.GroupIndex && ColorIndex == Other.ColorIndex && ColorCode == Other.ColorCode &&
+            StepShow == Other.StepShow && StepHide == Other.StepHide && PivotMatrix == Other.PivotMatrix &&
+            PivotPointValid == Other.PivotPointValid && ControlPoints == Other.ControlPoints &&
+            Position == Other.Position && Rotation == Other.Rotation;
+	}
 };
 
 class lcPiece : public lcObject
 {
 public:
+	lcPiece();
 	lcPiece(PieceInfo* Info);
 	lcPiece(const lcPiece& Other);
 	virtual ~lcPiece();
@@ -60,8 +93,8 @@ public:
 	bool HasKeyFrame(lcObjectPropertyId PropertyId, lcStep Time) const override;
 	bool SetKeyFrame(lcObjectPropertyId PropertyId, lcStep Time, bool KeyFrame) override;
 	void RemoveKeyFrames() override;
-	bool SaveUndoData(QDataStream& Stream, const lcModel* Model) const override;
-	bool LoadUndoData(QDataStream& Stream, const lcModel* Model) override;
+	lcPieceHistoryState GetHistoryState(const lcModel* Model) const;
+	void SetHistoryState(const lcPieceHistoryState& State, const lcModel* Model);
 
 	void AddMainModelRenderMeshes(lcScene* Scene, bool Highlight, bool Fade) const;
 	void AddSubModelRenderMeshes(lcScene* Scene, const lcMatrix44& WorldMatrix, int DefaultColorIndex, lcRenderMeshState RenderMeshState, bool ParentActive) const;
@@ -240,10 +273,10 @@ public:
 	}
 
 public:
-	PieceInfo* mPieceInfo;
+	PieceInfo* mPieceInfo = nullptr;
 
 	lcMatrix44 mModelWorld;
-	lcMatrix44 mPivotMatrix;
+	lcMatrix44 mPivotMatrix = lcMatrix44Identity();
 
 protected:
 	void UpdateMesh();
@@ -266,13 +299,13 @@ protected:
 	int mFileLine = -1;
 	QString mID;
 
-	lcGroup* mGroup;
+	lcGroup* mGroup = nullptr;
 
 	int mColorIndex;
 	quint32 mColorCode;
 
-	lcStep mStepShow;
-	lcStep mStepHide;
+	lcStep mStepShow = 1;
+	lcStep mStepHide = LC_STEP_MAX;
 
 	bool mPivotPointValid = false;
 	std::vector<lcPieceControlPoint> mControlPoints;