diff --git a/FDTD/engine.cpp b/FDTD/engine.cpp
index 5c7561e..eb05a67 100644
--- a/FDTD/engine.cpp
+++ b/FDTD/engine.cpp
@@ -30,25 +30,29 @@ Engine* Engine::New(const Operator* op)
 Engine::Engine(const Operator* op)
 {
 	Op = op;
+	for (int n=0;n<3;++n)
+	{
+		numLines[n] = Op->GetNumberOfLines(n);
+	}
 }
 
 Engine::~Engine()
 {
-	Reset();
+	this->Reset();
 }
 
 void Engine::Init()
 {
 	numTS = 0;
-	volt = Create_N_3DArray(Op->numLines);
-	curr = Create_N_3DArray(Op->numLines);
+	volt = Create_N_3DArray(numLines);
+	curr = Create_N_3DArray(numLines);
 }
 
 void Engine::Reset()
 {
-	Delete_N_3DArray(volt,Op->numLines);
+	Delete_N_3DArray(volt,numLines);
 	volt=NULL;
-	Delete_N_3DArray(curr,Op->numLines);
+	Delete_N_3DArray(curr,numLines);
 	curr=NULL;
 }
 
@@ -58,13 +62,13 @@ inline void Engine::UpdateVoltages()
 	bool shift[3];
 
 	//voltage updates
-	for (pos[0]=0;pos[0]<Op->numLines[0];++pos[0])
+	for (pos[0]=0;pos[0]<numLines[0];++pos[0])
 	{
 		shift[0]=pos[0];
-		for (pos[1]=0;pos[1]<Op->numLines[1];++pos[1])
+		for (pos[1]=0;pos[1]<numLines[1];++pos[1])
 		{
 			shift[1]=pos[1];
-			for (pos[2]=0;pos[2]<Op->numLines[2];++pos[2])
+			for (pos[2]=0;pos[2]<numLines[2];++pos[2])
 			{
 				shift[2]=pos[2];
 				//do the updates here
@@ -100,11 +104,11 @@ inline void Engine::ApplyVoltageExcite()
 inline void Engine::UpdateCurrents()
 {
 	unsigned int pos[3];
-	for (pos[0]=0;pos[0]<Op->numLines[0]-1;++pos[0])
+	for (pos[0]=0;pos[0]<numLines[0]-1;++pos[0])
 	{
-		for (pos[1]=0;pos[1]<Op->numLines[1]-1;++pos[1])
+		for (pos[1]=0;pos[1]<numLines[1]-1;++pos[1])
 		{
-			for (pos[2]=0;pos[2]<Op->numLines[2]-1;++pos[2])
+			for (pos[2]=0;pos[2]<numLines[2]-1;++pos[2])
 			{
 				//do the updates here
 				//for x
diff --git a/FDTD/engine.h b/FDTD/engine.h
index 230b2ad..c6f020f 100644
--- a/FDTD/engine.h
+++ b/FDTD/engine.h
@@ -46,6 +46,8 @@ protected:
 	virtual inline void UpdateCurrents();
 	virtual inline void ApplyCurrentExcite();
 
+	unsigned int numLines[3];
+
 	FDTD_FLOAT**** volt;
 	FDTD_FLOAT**** curr;
 	unsigned int numTS;
diff --git a/FDTD/engine_multithread.cpp b/FDTD/engine_multithread.cpp
index 8d140a2..27f389f 100644
--- a/FDTD/engine_multithread.cpp
+++ b/FDTD/engine_multithread.cpp
@@ -87,14 +87,14 @@ void Engine_Multithread::Init()
 	m_startBarrier = new boost::barrier(m_numThreads+1); // numThread workers + 1 controller
 	m_stopBarrier = new boost::barrier(m_numThreads+1); // numThread workers + 1 controller
 
-	unsigned int linesPerThread = round((float)Op->numLines[0] / (float)m_numThreads);
+	unsigned int linesPerThread = round((float)numLines[0] / (float)m_numThreads);
 	for (unsigned int n=0; n<m_numThreads; n++) {
 		unsigned int start = n * linesPerThread;
 		unsigned int stop = (n+1) * linesPerThread - 1;
 		unsigned int stop_h = stop;
 		if (n == m_numThreads-1) {
 			// last thread
-			stop = Op->numLines[0]-1;
+			stop = numLines[0]-1;
 			stop_h = stop-1;
 		}
 		//NS_Engine_Multithread::DBG().cout() << "###DEBUG## Thread " << n << ": start=" << start << " stop=" << stop  << " stop_h=" << stop_h << std::endl;
@@ -176,10 +176,10 @@ void thread::operator()()
 			for (pos[0]=m_start;pos[0]<=m_stop;++pos[0])
 			{
 				shift[0]=pos[0];
-				for (pos[1]=0;pos[1]<m_enginePtr->Op->numLines[1];++pos[1])
+				for (pos[1]=0;pos[1]<m_enginePtr->numLines[1];++pos[1])
 				{
 					shift[1]=pos[1];
-					for (pos[2]=0;pos[2]<m_enginePtr->Op->numLines[2];++pos[2])
+					for (pos[2]=0;pos[2]<m_enginePtr->numLines[2];++pos[2])
 					{
 						shift[2]=pos[2];
 						//do the updates here
@@ -218,9 +218,9 @@ void thread::operator()()
 			//current updates
 			for (pos[0]=m_start;pos[0]<=m_stop_h;++pos[0])
 			{
-				for (pos[1]=0;pos[1]<m_enginePtr->Op->numLines[1]-1;++pos[1])
+				for (pos[1]=0;pos[1]<m_enginePtr->numLines[1]-1;++pos[1])
 				{
-					for (pos[2]=0;pos[2]<m_enginePtr->Op->numLines[2]-1;++pos[2])
+					for (pos[2]=0;pos[2]<m_enginePtr->numLines[2]-1;++pos[2])
 					{
 						//do the updates here
 						//for x
diff --git a/FDTD/operator.cpp b/FDTD/operator.cpp
index 5c7eed1..559f7f6 100644
--- a/FDTD/operator.cpp
+++ b/FDTD/operator.cpp
@@ -105,15 +105,32 @@ unsigned int Operator::CalcNyquistNum(double fmax)
 bool Operator::SnapToMesh(double* dcoord, unsigned int* uicoord, bool lower, bool* inside)
 {
 	bool ok=true;
+	unsigned int numLines[3];
 	for (int n=0;n<3;++n)
 	{
+		numLines[n] = GetNumberOfLines(n);
 		if (inside) //set defaults
 			inside[n] = true;
 		uicoord[n]=0;
-		if (dcoord[n]<discLines[n][0]) {ok=false;uicoord[n]=0; if (inside) inside[n] = false;}
-		else if (dcoord[n]==discLines[n][0]) {uicoord[n]=0;}
-		else if (dcoord[n]>discLines[n][numLines[n]-1]) {ok=false;uicoord[n]=numLines[n]-1; if (lower) uicoord[n]=numLines[n]-2; if (inside) inside[n] = false; }
-		else if (dcoord[n]==discLines[n][numLines[n]-1]) {uicoord[n]=numLines[n]-1; if (lower) uicoord[n]=numLines[n]-2;}
+		if (dcoord[n]<discLines[n][0])
+		{
+			ok=false;uicoord[n]=0;
+			if (inside) inside[n] = false;
+		}
+		else if (dcoord[n]==discLines[n][0])
+			uicoord[n]=0;
+		else if (dcoord[n]>discLines[n][numLines[n]-1])
+		{
+			ok=false;
+			uicoord[n]=numLines[n]-1;
+			if (lower) uicoord[n]=numLines[n]-2;
+			if (inside) inside[n] = false;
+		}
+		else if (dcoord[n]==discLines[n][numLines[n]-1])
+		{
+			uicoord[n]=numLines[n]-1;
+			if (lower) uicoord[n]=numLines[n]-2;
+		}
 		else
 			for (unsigned int i=1;i<numLines[n];++i)
 			{
@@ -516,7 +533,6 @@ void Operator::ApplyElectricBC(bool* dirs)
 {
 	if (dirs==NULL) return;
 	unsigned int pos[3];
-	unsigned int ipos;
 	for (int n=0;n<3;++n)
 	{
 		int nP = (n+1)%3;
diff --git a/FDTD/operator.h b/FDTD/operator.h
index 623cc2c..16151cd 100644
--- a/FDTD/operator.h
+++ b/FDTD/operator.h
@@ -56,6 +56,8 @@ public:
 	double GetTimestep() const {return dT;};
 	double GetNumberCells() const;
 
+	virtual unsigned int GetNumberOfLines(int ny) const {return numLines[ny];}
+
 	void SetNyquistNum(unsigned int nyquist) {m_nyquistTS=nyquist;}
 	unsigned int GetNyquistNum() const {return m_nyquistTS;};
 	unsigned int CalcNyquistNum(double fmax);
@@ -108,9 +110,10 @@ protected:
 	double* EC_L[3];
 	double* EC_R[3];
 
-// engine/post-proc needs access
-public:
 	unsigned int numLines[3];
+
+	// engine/post-proc needs access
+public:
 	double* discLines[3];
 	double gridDelta;
 	AdrOp* MainOp;
diff --git a/FDTD/processcurrent.cpp b/FDTD/processcurrent.cpp
index 60891f8..e6ad194 100644
--- a/FDTD/processcurrent.cpp
+++ b/FDTD/processcurrent.cpp
@@ -66,8 +66,9 @@ int ProcessCurrent::Process()
 			m_start_inside[n] = m_stop_inside[n];
 			m_stop_inside[n] = b_help;
 		}
+		if (m_stop_inside[n]==false) // integrate up to the wall, Operator::SnapToMesh would give numLines[n]-2
+			stop[n]=Op->GetNumberOfLines(n)-1;
 	}
-
 	//x-current
 	if (m_start_inside[1] && m_start_inside[2])
 		for (unsigned int i=start[0];i<stop[0];++i)
diff --git a/FDTD/processfields.cpp b/FDTD/processfields.cpp
index cb0facd..b18e62a 100644
--- a/FDTD/processfields.cpp
+++ b/FDTD/processfields.cpp
@@ -173,11 +173,11 @@ double ProcessFields::CalcTotalEnergy()
 	double energy=0;
 	if (Eng==NULL) return 0.0;
 	unsigned int pos[3];
-	for (pos[0]=0;pos[0]<Op->numLines[0];++pos[0])
+	for (pos[0]=0;pos[0]<Op->GetNumberOfLines(0);++pos[0])
 	{
-		for (pos[1]=0;pos[1]<Op->numLines[1];++pos[1])
+		for (pos[1]=0;pos[1]<Op->GetNumberOfLines(1);++pos[1])
 		{
-			for (pos[2]=0;pos[2]<Op->numLines[2];++pos[2])
+			for (pos[2]=0;pos[2]<Op->GetNumberOfLines(2);++pos[2])
 			{
 				energy+=fabs(volt[0][pos[0]][pos[1]][pos[2]] * curr[1][pos[0]][pos[1]][pos[2]]);
 				energy+=fabs(volt[0][pos[0]][pos[1]][pos[2]] * curr[2][pos[0]][pos[1]][pos[2]]);