diff --git a/Common/processfields.cpp b/Common/processfields.cpp
index 38a7eb4..1346758 100644
--- a/Common/processfields.cpp
+++ b/Common/processfields.cpp
@@ -460,3 +460,53 @@ bool ProcessFields::DumpVectorArray2HDF5(string filename, string name, FDTD_FLOA
 	dataset.write( hdf5array, H5::PredType::NATIVE_FLOAT );
 	return true;
 }
+
+FDTD_FLOAT**** ProcessFields::CalcField()
+{
+	unsigned int pos[3];
+	unsigned int OpPos[3];
+	double out[3];
+	//create array
+	FDTD_FLOAT**** field = Create_N_3DArray<FDTD_FLOAT>(numLines);
+	if (m_DumpType==E_FIELD_DUMP)
+	{
+		for (pos[0]=0; pos[0]<numLines[0]; ++pos[0])
+		{
+			OpPos[0]=start[0]+pos[0]*subSample[0];
+			for (pos[1]=0; pos[1]<numLines[1]; ++pos[1])
+			{
+				OpPos[1]=start[1]+pos[1]*subSample[1];
+				for (pos[2]=0; pos[2]<numLines[2]; ++pos[2])
+				{
+					OpPos[2]=start[2]+pos[2]*subSample[2];
+					m_Eng_Interface->GetEField(OpPos,out);
+					field[0][pos[0]][pos[1]][pos[2]] = out[0];
+					field[1][pos[0]][pos[1]][pos[2]] = out[1];
+					field[2][pos[0]][pos[1]][pos[2]] = out[2];
+				}
+			}
+		}
+	}
+
+	if (m_DumpType==H_FIELD_DUMP)
+	{
+		for (pos[0]=0; pos[0]<numLines[0]; ++pos[0])
+		{
+			OpPos[0]=start[0]+pos[0]*subSample[0];
+			for (pos[1]=0; pos[1]<numLines[1]; ++pos[1])
+			{
+				OpPos[1]=start[1]+pos[1]*subSample[1];
+				for (pos[2]=0; pos[2]<numLines[2]; ++pos[2])
+				{
+					OpPos[2]=start[2]+pos[2]*subSample[2];
+					m_Eng_Interface->GetHField(OpPos,out);
+					field[0][pos[0]][pos[1]][pos[2]] = out[0];
+					field[1][pos[0]][pos[1]][pos[2]] = out[1];
+					field[2][pos[0]][pos[1]][pos[2]] = out[2];
+				}
+			}
+		}
+	}
+	return field;
+}
+
diff --git a/Common/processfields.h b/Common/processfields.h
index 914c881..75a750c 100644
--- a/Common/processfields.h
+++ b/Common/processfields.h
@@ -91,6 +91,9 @@ protected:
 	//! dump mesh
 	unsigned int numLines[3];
 	double* discLines[3];
+
+	//! Calculate and return the defined field. Caller has to cleanup the array.
+	FDTD_FLOAT**** CalcField();
 };
 
 #endif // PROCESSFIELDS_H
diff --git a/Common/processfields_td.cpp b/Common/processfields_td.cpp
index da41136..107afa6 100644
--- a/Common/processfields_td.cpp
+++ b/Common/processfields_td.cpp
@@ -53,50 +53,7 @@ int ProcessFieldsTD::Process()
 	double discLines_scaling = Op->GetGridDelta();
 #endif
 
-	unsigned int pos[3];
-	unsigned int OpPos[3];
-	double out[3];
-	//create array
-	FDTD_FLOAT**** field = Create_N_3DArray<FDTD_FLOAT>(numLines);
-	if (m_DumpType==E_FIELD_DUMP)
-	{
-		for (pos[0]=0; pos[0]<numLines[0]; ++pos[0])
-		{
-			OpPos[0]=start[0]+pos[0]*subSample[0];
-			for (pos[1]=0; pos[1]<numLines[1]; ++pos[1])
-			{
-				OpPos[1]=start[1]+pos[1]*subSample[1];
-				for (pos[2]=0; pos[2]<numLines[2]; ++pos[2])
-				{
-					OpPos[2]=start[2]+pos[2]*subSample[2];
-					m_Eng_Interface->GetEField(OpPos,out);
-					field[0][pos[0]][pos[1]][pos[2]] = out[0];
-					field[1][pos[0]][pos[1]][pos[2]] = out[1];
-					field[2][pos[0]][pos[1]][pos[2]] = out[2];
-				}
-			}
-		}
-	}
-
-	if (m_DumpType==H_FIELD_DUMP)
-	{
-		for (pos[0]=0; pos[0]<numLines[0]; ++pos[0])
-		{
-			OpPos[0]=start[0]+pos[0]*subSample[0];
-			for (pos[1]=0; pos[1]<numLines[1]; ++pos[1])
-			{
-				OpPos[1]=start[1]+pos[1]*subSample[1];
-				for (pos[2]=0; pos[2]<numLines[2]; ++pos[2])
-				{
-					OpPos[2]=start[2]+pos[2]*subSample[2];
-					m_Eng_Interface->GetHField(OpPos,out);
-					field[0][pos[0]][pos[1]][pos[2]] = out[0];
-					field[1][pos[0]][pos[1]][pos[2]] = out[1];
-					field[2][pos[0]][pos[1]][pos[2]] = out[2];
-				}
-			}
-		}
-	}
+	FDTD_FLOAT**** field = CalcField();
 
 	if (m_fileType==VTK_FILETYPE)
 	{
@@ -119,6 +76,5 @@ int ProcessFieldsTD::Process()
 
 	Delete_N_3DArray(field,numLines);
 
-
 	return GetNextInterval();
 }