diff --git a/libsrc/include/nginterface.h b/libsrc/include/nginterface.h
index 2d23ba41..e120f57c 100644
--- a/libsrc/include/nginterface.h
+++ b/libsrc/include/nginterface.h
@@ -175,9 +175,9 @@ extern "C" {
   /// x ..global coordinates
   /// dxdxi...D x D Jacobian matrix (row major storage)
   DLL_HEADER void Ng_GetMultiElementTransformation (int ei, int n,
-                                                    const double * xi, int sxi,
-                                                    double * x, int sx,
-                                                    double * dxdxi, int sdxdxi);
+                                                    const double * xi, size_t sxi,
+                                                    double * x, size_t sx,
+                                                    double * dxdxi, size_t sdxdxi);
 
   
   
diff --git a/libsrc/include/nginterface_v2.hpp b/libsrc/include/nginterface_v2.hpp
index 1c843334..809b41fb 100644
--- a/libsrc/include/nginterface_v2.hpp
+++ b/libsrc/include/nginterface_v2.hpp
@@ -130,9 +130,9 @@ namespace netgen
   /// dxdxi...DIM_SPACE x DIM_EL Jacobian matrix (row major storage)
   template <int DIM_EL, int DIM_SPACE> 
   DLL_HEADER void Ng_MultiElementTransformation (int elnr, int npts,
-                                                 const double * xi, int sxi,
-                                                 double * x, int sx,
-                                                 double * dxdxi, int sdxdxi);
+                                                 const double * xi, size_t sxi,
+                                                 double * x, size_t sx,
+                                                 double * dxdxi, size_t sdxdxi);
   
   template <int DIM> 
   DLL_HEADER int Ng_GetElementIndex (int nr);
diff --git a/libsrc/meshing/curvedelems.cpp b/libsrc/meshing/curvedelems.cpp
index b821521f..6a7a5d5d 100644
--- a/libsrc/meshing/curvedelems.cpp
+++ b/libsrc/meshing/curvedelems.cpp
@@ -2884,9 +2884,9 @@ namespace netgen
   template <int DIM_SPACE>
   void CurvedElements :: 
   CalcMultiPointSurfaceTransformation (SurfaceElementIndex elnr, int npts,
-				       const double * xi, int sxi,
-                                       double * x, int sx,
-                                       double * dxdxi, int sdxdxi)
+				       const double * xi, size_t sxi,
+                                       double * x, size_t sx,
+                                       double * dxdxi, size_t sdxdxi)
   {
     if (mesh.coarsemesh)
       {
@@ -3031,15 +3031,15 @@ namespace netgen
 
   template void CurvedElements :: 
   CalcMultiPointSurfaceTransformation<2> (SurfaceElementIndex elnr, int npts,
-                                          const double * xi, int sxi,
-                                          double * x, int sx,
-                                          double * dxdxi, int sdxdxi);
+                                          const double * xi, size_t sxi,
+                                          double * x, size_t sx,
+                                          double * dxdxi, size_t sdxdxi);
 
   template void CurvedElements :: 
   CalcMultiPointSurfaceTransformation<3> (SurfaceElementIndex elnr, int npts,
-                                          const double * xi, int sxi,
-                                          double * x, int sx,
-                                          double * dxdxi, int sdxdxi);
+                                          const double * xi, size_t sxi,
+                                          double * x, size_t sx,
+                                          double * dxdxi, size_t sdxdxi);
 
 
 
@@ -3200,9 +3200,9 @@ namespace netgen
 
   void  CurvedElements :: 
   CalcMultiPointElementTransformation (ElementIndex elnr, int n,
-                                       const double * xi, int sxi,
-                                       double * x, int sx,
-                                       double * dxdxi, int sdxdxi)
+                                       const double * xi, size_t sxi,
+                                       double * x, size_t sx,
+                                       double * dxdxi, size_t sdxdxi)
   {
     if (mesh.coarsemesh)
       {
diff --git a/libsrc/meshing/curvedelems.hpp b/libsrc/meshing/curvedelems.hpp
index b88e66b6..e6735f37 100644
--- a/libsrc/meshing/curvedelems.hpp
+++ b/libsrc/meshing/curvedelems.hpp
@@ -125,9 +125,9 @@ public:
   
   template <int DIM_SPACE>
   void CalcMultiPointSurfaceTransformation (SurfaceElementIndex elnr, int n,
-                                            const double * xi, int sxi,
-                                            double * x, int sx,
-                                            double * dxdxi, int sdxdxi);
+                                            const double * xi, size_t sxi,
+                                            double * x, size_t sx,
+                                            double * dxdxi, size_t sdxdxi);
 
 
   void CalcMultiPointElementTransformation (Array< Point<3> > * xi, ElementIndex elnr,
@@ -135,9 +135,9 @@ public:
 					    Array< Mat<3,3> > * dxdxi);
 
   void CalcMultiPointElementTransformation (ElementIndex elnr, int n,
-                                            const double * xi, int sxi,
-                                            double * x, int sx,
-                                            double * dxdxi, int sdxdxi);
+                                            const double * xi, size_t sxi,
+                                            double * x, size_t sx,
+                                            double * dxdxi, size_t sdxdxi);
 
 
 
diff --git a/ng/nginterface.cpp b/ng/nginterface.cpp
index 962f18f6..ea4c6a48 100644
--- a/ng/nginterface.cpp
+++ b/ng/nginterface.cpp
@@ -920,9 +920,9 @@ void Ng_GetBufferedElementTransformation (int ei, const double * xi,
 
 
 void Ng_GetMultiElementTransformation (int ei, int n,
-                                       const double * xi, int sxi,
-                                       double * x, int sx,
-                                       double * dxdxi, int sdxdxi)
+                                       const double * xi, size_t sxi,
+                                       double * x, size_t sx,
+                                       double * dxdxi, size_t sdxdxi)
 {
   if (mesh->GetDimension() == 2)
     mesh->GetCurvedElements().CalcMultiPointSurfaceTransformation<2> (ei-1, n, xi, sxi, x, sx, dxdxi, sdxdxi);
diff --git a/ng/nginterface_v2.cpp b/ng/nginterface_v2.cpp
index 8fb119e0..3be2a8f9 100644
--- a/ng/nginterface_v2.cpp
+++ b/ng/nginterface_v2.cpp
@@ -185,36 +185,36 @@ namespace netgen
   
   template <>
   DLL_HEADER void Ng_MultiElementTransformation<3,3> (int elnr, int npts,
-                                                      const double * xi, int sxi,
-                                                      double * x, int sx,
-                                                      double * dxdxi, int sdxdxi)
+                                                      const double * xi, size_t sxi,
+                                                      double * x, size_t sx,
+                                                      double * dxdxi, size_t sdxdxi)
   {
     mesh->GetCurvedElements().CalcMultiPointElementTransformation (elnr, npts, xi, sxi, x, sx, dxdxi, sdxdxi);
   }
   
   template <>
   DLL_HEADER void Ng_MultiElementTransformation<2,2> (int elnr, int npts,
-                                                      const double * xi, int sxi,
-                                                      double * x, int sx,
-                                                      double * dxdxi, int sdxdxi)
+                                                      const double * xi, size_t sxi,
+                                                      double * x, size_t sx,
+                                                      double * dxdxi, size_t sdxdxi)
   {
     mesh->GetCurvedElements().CalcMultiPointSurfaceTransformation<2> (elnr, npts, xi, sxi, x, sx, dxdxi, sdxdxi);
   }
 
   template <>
   DLL_HEADER void Ng_MultiElementTransformation<2,3> (int elnr, int npts,
-                                                      const double * xi, int sxi,
-                                                      double * x, int sx,
-                                                      double * dxdxi, int sdxdxi)
+                                                      const double * xi, size_t sxi,
+                                                      double * x, size_t sx,
+                                                      double * dxdxi, size_t sdxdxi)
   {
     mesh->GetCurvedElements().CalcMultiPointSurfaceTransformation<3> (elnr, npts, xi, sxi, x, sx, dxdxi, sdxdxi);
   }
 
   template <>
   DLL_HEADER void Ng_MultiElementTransformation<1,2> (int elnr, int npts,
-                                                      const double * xi, int sxi,
-                                                      double * x, int sx,
-                                                      double * dxdxi, int sdxdxi)
+                                                      const double * xi, size_t sxi,
+                                                      double * x, size_t sx,
+                                                      double * dxdxi, size_t sdxdxi)
   {
     for (int ip = 0; ip < npts; ip++)
       {
@@ -235,9 +235,9 @@ namespace netgen
 
   template <>
   DLL_HEADER void Ng_MultiElementTransformation<1,1> (int elnr, int npts,
-                                                      const double * xi, int sxi,
-                                                      double * x, int sx,
-                                                      double * dxdxi, int sdxdxi)
+                                                      const double * xi, size_t sxi,
+                                                      double * x, size_t sx,
+                                                      double * dxdxi, size_t sdxdxi)
   {
     cout << "1D not supported" << endl;
   }
diff --git a/windows/netgen.vcproj b/windows/netgen.vcproj
index 666186bc..ca8794da 100644
--- a/windows/netgen.vcproj
+++ b/windows/netgen.vcproj
@@ -327,7 +327,7 @@
 				EnableEnhancedInstructionSet="1"
 				UsePrecompiledHeader="0"
 				WarningLevel="2"
-				Detect64BitPortabilityProblems="true"
+				Detect64BitPortabilityProblems="false"
 				DebugInformationFormat="3"
 			/>
 			<Tool
@@ -944,11 +944,11 @@
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\gprim\gprim.hpp"
+				RelativePath="..\libsrc\include\gprim.hpp"
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\include\gprim.hpp"
+				RelativePath="..\libsrc\gprim\gprim.hpp"
 				>
 			</File>
 			<File
@@ -1032,11 +1032,11 @@
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\include\meshing.hpp"
+				RelativePath="..\libsrc\meshing\meshing.hpp"
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\meshing\meshing.hpp"
+				RelativePath="..\libsrc\include\meshing.hpp"
 				>
 			</File>
 			<File
@@ -1116,11 +1116,11 @@
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\occ\occgeom.hpp"
+				RelativePath="..\libsrc\include\occgeom.hpp"
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\include\occgeom.hpp"
+				RelativePath="..\libsrc\occ\occgeom.hpp"
 				>
 			</File>
 			<File
@@ -1128,11 +1128,11 @@
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\linalg\opti.hpp"
+				RelativePath="..\libsrc\include\opti.hpp"
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\include\opti.hpp"
+				RelativePath="..\libsrc\linalg\opti.hpp"
 				>
 			</File>
 			<File
@@ -1240,11 +1240,11 @@
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\stlgeom\stlgeom.hpp"
+				RelativePath="..\libsrc\include\stlgeom.hpp"
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\include\stlgeom.hpp"
+				RelativePath="..\libsrc\stlgeom\stlgeom.hpp"
 				>
 			</File>
 			<File
@@ -1308,11 +1308,11 @@
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\include\visual.hpp"
+				RelativePath="..\libsrc\visualization\visual.hpp"
 				>
 			</File>
 			<File
-				RelativePath="..\libsrc\visualization\visual.hpp"
+				RelativePath="..\libsrc\include\visual.hpp"
 				>
 			</File>
 			<File