diff --git a/xs/MANIFEST b/xs/MANIFEST
index 9514db695c..541ad30d53 100644
--- a/xs/MANIFEST
+++ b/xs/MANIFEST
@@ -37,6 +37,8 @@ src/ppport.h
 src/Surface.cpp
 src/Surface.hpp
 src/SurfaceCollection.hpp
+src/SVG.cpp
+src/SVG.hpp
 src/TriangleMesh.cpp
 src/TriangleMesh.hpp
 src/utils.cpp
diff --git a/xs/src/SVG.cpp b/xs/src/SVG.cpp
new file mode 100644
index 0000000000..a8337283a9
--- /dev/null
+++ b/xs/src/SVG.cpp
@@ -0,0 +1,34 @@
+#include "SVG.hpp"
+
+namespace Slic3r {
+
+SVG::SVG(const char* filename)
+{
+    this->f = fopen(filename, "w");
+    fprintf(this->f,
+        "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n"
+        "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" \"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n"
+        "<svg height=\"2000\" width=\"2000\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:svg=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">\n"
+	    "   <marker id=\"endArrow\" markerHeight=\"8\" markerUnits=\"strokeWidth\" markerWidth=\"10\" orient=\"auto\" refX=\"1\" refY=\"5\" viewBox=\"0 0 10 10\">\n"
+		"      <polyline fill=\"darkblue\" points=\"0,0 10,5 0,10 1,5\" />\n"
+	    "   </marker>\n"
+	    );
+}
+
+void
+SVG::AddLine(const Line &line)
+{
+    fprintf(this->f,
+        "   <line x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" style=\"stroke: black; stroke-width: 2\" marker-end=\"url(#endArrow)\"/>\n",
+        (float)unscale(line.a.x)*10, (float)unscale(line.a.y)*10, (float)unscale(line.b.x)*10, (float)unscale(line.b.y)*10
+        );
+}
+
+void
+SVG::Close()
+{
+    fprintf(this->f, "</svg>\n");
+    fclose(this->f);
+}
+
+}
diff --git a/xs/src/SVG.hpp b/xs/src/SVG.hpp
new file mode 100644
index 0000000000..2a22ed97e6
--- /dev/null
+++ b/xs/src/SVG.hpp
@@ -0,0 +1,21 @@
+#ifndef slic3r_SVG_hpp_
+#define slic3r_SVG_hpp_
+
+#include <myinit.h>
+#include "Line.hpp"
+
+namespace Slic3r {
+
+class SVG
+{
+    private:
+    FILE* f;
+    public:
+    SVG(const char* filename);
+    void AddLine(const Line &line);
+    void Close();
+};
+
+}
+
+#endif
diff --git a/xs/src/TriangleMesh.cpp b/xs/src/TriangleMesh.cpp
index c512757c24..d2c134aa4a 100644
--- a/xs/src/TriangleMesh.cpp
+++ b/xs/src/TriangleMesh.cpp
@@ -9,6 +9,10 @@
 #include <math.h>
 #include <assert.h>
 
+#ifdef SLIC3R_DEBUG
+#include "SVG.hpp"
+#endif
+
 namespace Slic3r {
 
 TriangleMesh::TriangleMesh()
@@ -281,9 +285,6 @@ TriangleMesh::slice(const std::vector<double> &z)
                 
                 if (a->z == b->z && a->z == slice_z) {
                     // edge is horizontal and belongs to the current layer
-                    #ifdef SLIC3R_DEBUG
-                    printf("Edge is horizontal!\n");
-                    #endif
                     
                     /* We assume that this method is never being called for horizontal
                        facets, so no other edge is going to be on this layer. */
@@ -308,10 +309,6 @@ TriangleMesh::slice(const std::vector<double> &z)
                     found_horizontal_edge = true;
                     break;
                 } else if (a->z == slice_z) {
-                    #ifdef SLIC3R_DEBUG
-                    printf("A point on plane!\n");
-                    #endif
-                    
                     IntersectionPoint point;
                     point.x         = a->x;
                     point.y         = a->y;
@@ -319,10 +316,6 @@ TriangleMesh::slice(const std::vector<double> &z)
                     points.push_back(point);
                     points_on_layer.push_back(points.size()-1);
                 } else if (b->z == slice_z) {
-                    #ifdef SLIC3R_DEBUG
-                    printf("B point on plane!\n");
-                    #endif
-                    
                     IntersectionPoint point;
                     point.x         = b->x;
                     point.y         = b->y;
@@ -331,9 +324,6 @@ TriangleMesh::slice(const std::vector<double> &z)
                     points_on_layer.push_back(points.size()-1);
                 } else if ((a->z < slice_z && b->z > slice_z) || (b->z < slice_z && a->z > slice_z)) {
                     // edge intersects the current layer; calculate intersection
-                    #ifdef SLIC3R_DEBUG
-                    printf("Intersects!\n");
-                    #endif
                     
                     IntersectionPoint point;
                     point.x         = b->x + (a->x - b->x) * (slice_z - b->z) / (a->z - b->z);
@@ -345,14 +335,14 @@ TriangleMesh::slice(const std::vector<double> &z)
             }
             if (found_horizontal_edge) continue;
             
-            if (points_on_layer.size() == 2) {
-                if (intersection_points.size() == 1) {
-                    points.erase( points.begin() + points_on_layer[1] );
-                } else if (intersection_points.empty()) {
-                    if (points[ points_on_layer[0] ].coincides_with(&points[ points_on_layer[1] ])) {
-                        continue;
-                    }
-                }
+            if (!points_on_layer.empty()) {
+                // we can't have only one point on layer because each vertex gets detected
+                // twice (once for each edge), and we can't have three points on layer because
+                // we assume this code is not getting called for horizontal facets
+                assert(points_on_layer.size() == 2);
+                assert( points[ points_on_layer[0] ].point_id == points[ points_on_layer[1] ].point_id );
+                points.erase( points.begin() + points_on_layer[1] );
+                if (intersection_points.empty()) continue;
             }
             
             if (!points.empty()) {
diff --git a/xs/src/myinit.h b/xs/src/myinit.h
index fcd7d60e1f..d1659823e4 100644
--- a/xs/src/myinit.h
+++ b/xs/src/myinit.h
@@ -19,6 +19,8 @@ extern "C" {
 #endif
 
 #define EPSILON 1e-4
+#define SCALING_FACTOR 0.000001
+#define unscale(val) (val * SCALING_FACTOR)
 
 namespace Slic3r {}
 using namespace Slic3r;