diff --git a/common/lc_array.h b/common/lc_array.h
index 6f96ba35..84e8b50f 100644
--- a/common/lc_array.h
+++ b/common/lc_array.h
@@ -55,7 +55,12 @@ public:
 		return *this;
 	}
 
-	T& operator[](int Index) const
+	const T& operator[](int Index) const
+	{
+		return mData[Index];
+	}
+
+	T& operator[](int Index)
 	{
 		return mData[Index];
 	}
diff --git a/common/lc_category.cpp b/common/lc_category.cpp
index 265582a2..a6f58d25 100644
--- a/common/lc_category.cpp
+++ b/common/lc_category.cpp
@@ -147,7 +147,7 @@ bool lcSaveCategories(QTextStream& Stream, const lcArray<lcLibraryCategory>& Cat
 
 	for (int CategoryIdx = 0; CategoryIdx < Categories.GetSize(); CategoryIdx++)
 	{
-		lcLibraryCategory& Category = Categories[CategoryIdx];
+		const lcLibraryCategory& Category = Categories[CategoryIdx];
 		Stream << Format.arg((const char*)Category.Name, (const char*)Category.Keywords);
 	}
 
diff --git a/common/lc_context.cpp b/common/lc_context.cpp
index 8b9eee6e..1d67df03 100644
--- a/common/lc_context.cpp
+++ b/common/lc_context.cpp
@@ -964,7 +964,7 @@ void lcContext::DrawOpaqueMeshes(const lcArray<lcRenderMesh>& OpaqueMeshes)
 
 	for (int MeshIdx = 0; MeshIdx < OpaqueMeshes.GetSize(); MeshIdx++)
 	{
-		lcRenderMesh& RenderMesh = OpaqueMeshes[MeshIdx];
+		const lcRenderMesh& RenderMesh = OpaqueMeshes[MeshIdx];
 		lcMesh* Mesh = RenderMesh.Mesh;
 		int LodIndex = RenderMesh.LodIndex;
 
@@ -1041,7 +1041,7 @@ void lcContext::DrawTranslucentMeshes(const lcArray<lcRenderMesh>& TranslucentMe
 
 	for (int MeshIdx = 0; MeshIdx < TranslucentMeshes.GetSize(); MeshIdx++)
 	{
-		lcRenderMesh& RenderMesh = TranslucentMeshes[MeshIdx];
+		const lcRenderMesh& RenderMesh = TranslucentMeshes[MeshIdx];
 		lcMesh* Mesh = RenderMesh.Mesh;
 		int LodIndex = RenderMesh.LodIndex;
 
diff --git a/common/lc_library.cpp b/common/lc_library.cpp
index 59109eb1..814913cc 100644
--- a/common/lc_library.cpp
+++ b/common/lc_library.cpp
@@ -1030,7 +1030,7 @@ lcMesh* lcPiecesLibrary::CreateMesh(PieceInfo* Info, lcLibraryMeshData& MeshData
 		for (int VertexIdx = 0; VertexIdx < TexturedVertices.GetSize(); VertexIdx++)
 		{
 			lcVertexTextured& DstVertex = *DstTexturedVerts++;
-			lcVertexTextured& SrcVertex = TexturedVertices[VertexIdx];
+			const lcVertexTextured& SrcVertex = TexturedVertices[VertexIdx];
 
 			const lcVector3& SrcPosition = SrcVertex.Position;
 			lcVector3& DstPosition = DstVertex.Position;
@@ -1986,7 +1986,7 @@ void lcLibraryMeshData::AddMeshData(const lcLibraryMeshData& Data, const lcMatri
 
 			for (int SrcVertexIdx = 0; SrcVertexIdx < VertexCount; SrcVertexIdx++)
 			{
-				lcVertex& SrcVertex = DataVertices[SrcVertexIdx];
+				const lcVertex& SrcVertex = DataVertices[SrcVertexIdx];
 				lcVector3 Position = lcMul31(SrcVertex.Position, Transform);
 				lcVector2 TexCoord(lcDot3(lcVector3(Position.x, Position.y, Position.z), TextureMap->Params[0]) + TextureMap->Params[0].w,
 								   lcDot3(lcVector3(Position.x, Position.y, Position.z), TextureMap->Params[1]) + TextureMap->Params[1].w);
@@ -2027,7 +2027,7 @@ void lcLibraryMeshData::AddMeshData(const lcLibraryMeshData& Data, const lcMatri
 
 			for (int SrcVertexIdx = 0; SrcVertexIdx < TexturedVertexCount; SrcVertexIdx++)
 			{
-				lcVertexTextured& SrcVertex = DataTexturedVertices[SrcVertexIdx];
+				const lcVertexTextured& SrcVertex = DataTexturedVertices[SrcVertexIdx];
 				lcVector3 Position = lcMul31(SrcVertex.Position, Transform);
 				int Index = -1;
 
@@ -2137,7 +2137,7 @@ void lcLibraryMeshData::AddMeshDataNoDuplicateCheck(const lcLibraryMeshData& Dat
 
 			for (int SrcVertexIdx = 0; SrcVertexIdx < DataVertices.GetSize(); SrcVertexIdx++)
 			{
-				lcVertex& SrcVertex = DataVertices[SrcVertexIdx];
+				const lcVertex& SrcVertex = DataVertices[SrcVertexIdx];
 				lcVertexTextured& DstVertex = TexturedVertices.Add();
 
 				lcVector3 Position = lcMul31(SrcVertex.Position, Transform);
@@ -2160,7 +2160,7 @@ void lcLibraryMeshData::AddMeshDataNoDuplicateCheck(const lcLibraryMeshData& Dat
 
 			for (int SrcVertexIdx = 0; SrcVertexIdx < TexturedVertexCount; SrcVertexIdx++)
 			{
-				lcVertexTextured& SrcVertex = DataTexturedVertices[SrcVertexIdx];
+				const lcVertexTextured& SrcVertex = DataTexturedVertices[SrcVertexIdx];
 				lcVertexTextured& DstVertex = TexturedVertices.Add();
 				DstVertex.Position = lcMul31(SrcVertex.Position, Transform);
 				DstVertex.TexCoord = SrcVertex.TexCoord;
diff --git a/common/lc_synth.cpp b/common/lc_synth.cpp
index d9a45279..2e787485 100644
--- a/common/lc_synth.cpp
+++ b/common/lc_synth.cpp
@@ -415,7 +415,7 @@ void lcSynthInfo::AddFlexibleAxleParts(lcMemFile& File, lcLibraryMeshData& MeshD
 	}
 }
 
-void lcSynthInfo::AddStringBraidedParts(lcMemFile& File, lcLibraryMeshData& MeshData, const lcArray<lcMatrix44>& Sections) const
+void lcSynthInfo::AddStringBraidedParts(lcMemFile& File, lcLibraryMeshData& MeshData, lcArray<lcMatrix44>& Sections) const
 {
 	for (int SectionIdx = 0; SectionIdx < Sections.GetSize(); SectionIdx++)
 	{
diff --git a/common/lc_synth.h b/common/lc_synth.h
index 60849bf1..57b9a035 100644
--- a/common/lc_synth.h
+++ b/common/lc_synth.h
@@ -33,7 +33,7 @@ protected:
 	void CalculateSections(const lcArray<lcPieceControlPoint>& ControlPoints, lcArray<lcMatrix44>& Sections, void(*SectionCallback)(const lcVector3& CurvePoint, int SegmentIndex, float t, void* Param), void* CallbackParam) const;
 	void AddRibbedHoseParts(lcMemFile& File, const lcArray<lcMatrix44>& Sections) const;
 	void AddFlexibleAxleParts(lcMemFile& File, lcLibraryMeshData& MeshData, const lcArray<lcMatrix44>& Sections) const;
-	void AddStringBraidedParts(lcMemFile& File, lcLibraryMeshData& MeshData, const lcArray<lcMatrix44>& Sections) const;
+	void AddStringBraidedParts(lcMemFile& File, lcLibraryMeshData& MeshData, lcArray<lcMatrix44>& Sections) const;
 
 	lcSynthType mType;
 	lcSynthComponent mStart;
diff --git a/common/object.h b/common/object.h
index 12209122..265db857 100644
--- a/common/object.h
+++ b/common/object.h
@@ -93,7 +93,7 @@ protected:
 		const int Count = sizeof(T) / sizeof(float);
 		for (int KeyIdx = 0; KeyIdx < Keys.GetSize(); KeyIdx++)
 		{
-			lcObjectKey<T>& Key = Keys[KeyIdx];
+			const lcObjectKey<T>& Key = Keys[KeyIdx];
 			Stream << QLatin1String("0 !LEOCAD ") << KeyName << Key.Step << ' ';
 			for (int ValueIdx = 0; ValueIdx < Count; ValueIdx++)
 				Stream << ((float*)&Key.Value)[ValueIdx] << ' ';
@@ -120,7 +120,7 @@ protected:
 	template<typename T>
 	const T& CalculateKey(const lcArray<lcObjectKey<T>>& Keys, lcStep Step)
 	{
-		lcObjectKey<T>* PreviousKey = &Keys[0];
+		const lcObjectKey<T>* PreviousKey = &Keys[0];
 
 		for (int KeyIdx = 0; KeyIdx < Keys.GetSize(); KeyIdx++)
 		{
diff --git a/common/piece.h b/common/piece.h
index 56c24081..a1f9db34 100644
--- a/common/piece.h
+++ b/common/piece.h
@@ -473,7 +473,7 @@ public:
 
 			if (ControlPointIndex >= 0 && ControlPointIndex < mControlPoints.GetSize())
 			{
-				lcMatrix44& Transform = mControlPoints[ControlPointIndex].Transform;
+				const lcMatrix44& Transform = mControlPoints[ControlPointIndex].Transform;
 				return lcMul31(Transform.GetTranslation(), mModelWorld);
 			}
 
@@ -498,7 +498,7 @@ public:
 
 			if (ControlPointIndex >= 0 && ControlPointIndex < mControlPoints.GetSize())
 			{
-				lcMatrix44& Transform = mControlPoints[ControlPointIndex].Transform;
+				const lcMatrix44& Transform = mControlPoints[ControlPointIndex].Transform;
 				return lcMatrix33(lcMul(Transform, mModelWorld));
 			}