--- a/Framework/Layers/DicomStructureSetRendererFactory.cpp	Sun Oct 08 10:52:24 2017 +0200
+++ b/Framework/Layers/DicomStructureSetRendererFactory.cpp	Wed Nov 08 16:13:55 2017 +0100
@@ -49,7 +49,33 @@
       if (visible_)
       {
         cairo_set_line_width(context.GetObject(), 3.0f / view.GetZoom());
-        structureSet_.Render(context, slice_);
+
+        cairo_t* cr = context.GetObject();
+
+        for (size_t k = 0; k < structureSet_.GetStructureCount(); k++)
+        {
+          std::vector< std::vector<DicomStructureSet::PolygonPoint> >  polygons;
+
+          if (structureSet_.ProjectStructure(polygons, k, slice_))
+          {
+            uint8_t red, green, blue;
+            structureSet_.GetStructureColor(red, green, blue, k);
+            context.SetSourceColor(red, green, blue);
+
+            for (size_t i = 0; i < polygons.size(); i++)
+            {
+              cairo_move_to(cr, polygons[i][0].first, polygons[i][0].second);
+
+              for (size_t j = 1; j < polygons[i].size(); j++)
+              {
+                cairo_line_to(cr, polygons[i][j].first, polygons[i][j].second);
+              }
+
+              cairo_line_to(cr, polygons[i][0].first, polygons[i][0].second);
+              cairo_stroke(cr);
+            }
+          }
+        }
       }
 
       return true;
@@ -199,11 +225,7 @@
   
   void DicomStructureSetRendererFactory::ScheduleLayerCreation(const CoordinateSystem3D& viewportSlice)
   {
-    bool isOpposite;
-    if (structureSet_.get() != NULL &&
-        GeometryToolbox::IsParallelOrOpposite(isOpposite,
-                                              viewportSlice.GetNormal(),
-                                              structureSet_->GetNormal()))
+    if (structureSet_.get() != NULL)
     {
       NotifyLayerReady(new Renderer(*structureSet_, viewportSlice), viewportSlice, false);
     }

--- a/Framework/Toolbox/DicomStructureSet.cpp	Sun Oct 08 10:52:24 2017 +0200
+++ b/Framework/Toolbox/DicomStructureSet.cpp	Wed Nov 08 16:13:55 2017 +0100
@@ -152,7 +152,18 @@
   {
     if (index >= structures_.size())
     {
-      throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented);
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
+    }
+
+    return structures_[index];
+  }
+
+
+  DicomStructureSet::Structure& DicomStructureSet::GetStructure(size_t index)
+  {
+    if (index >= structures_.size())
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
     }
 
     return structures_[index];
@@ -336,47 +347,6 @@
   }
 
 
-  void DicomStructureSet::Render(CairoContext& context,
-                                 const CoordinateSystem3D& slice)
-  {
-    cairo_t* cr = context.GetObject();
-
-    for (Structures::iterator structure = structures_.begin();
-         structure != structures_.end(); ++structure)
-    {
-      for (Polygons::iterator polygon = structure->polygons_.begin();
-           polygon != structure->polygons_.end(); ++polygon)
-      {
-        polygon->UpdateReferencedSlice(referencedSlices_);
-          
-        if (polygon->IsOnSlice(slice))
-        {
-          context.SetSourceColor(structure->red_, structure->green_, structure->blue_);
-
-          Points::const_iterator p = polygon->GetPoints().begin();
-
-          double x, y;
-          slice.ProjectPoint(x, y, *p);
-          cairo_move_to(cr, x, y);
-          ++p;
-            
-          while (p != polygon->GetPoints().end())
-          {
-            slice.ProjectPoint(x, y, *p);
-            cairo_line_to(cr, x, y);
-            ++p;
-          }
-
-          slice.ProjectPoint(x, y, *polygon->GetPoints().begin());
-          cairo_line_to(cr, x, y);
-
-          cairo_stroke(cr);
-        }
-      }
-    }
-  }
-
-
   void DicomStructureSet::GetReferencedInstances(std::set<std::string>& instances)
   {
     for (Structures::const_iterator structure = structures_.begin();
@@ -532,4 +502,51 @@
     return result.release();
   }
 
+
+  bool DicomStructureSet::ProjectStructure(std::vector< std::vector<PolygonPoint> >& polygons,
+                                           Structure& structure,
+                                           const CoordinateSystem3D& slice)
+  {
+    polygons.clear();
+
+    Vector normal = GetNormal();
+    
+    bool isOpposite;    
+    if (GeometryToolbox::IsParallelOrOpposite(isOpposite, normal, slice.GetNormal()))
+    {
+      // This is an axial projection
+
+      for (Polygons::iterator polygon = structure.polygons_.begin();
+           polygon != structure.polygons_.end(); ++polygon)
+      {
+        polygon->UpdateReferencedSlice(referencedSlices_);
+          
+        if (polygon->IsOnSlice(slice))
+        {
+          polygons.push_back(std::vector<PolygonPoint>());
+          
+          for (Points::const_iterator p = polygon->GetPoints().begin();
+               p != polygon->GetPoints().end(); ++p)
+          {
+            double x, y;
+            slice.ProjectPoint(x, y, *p);
+            polygons.back().push_back(std::make_pair(x, y));
+          }
+        }
+      }
+
+      return true;
+    }
+    else if (GeometryToolbox::IsParallelOrOpposite(isOpposite, normal, slice.GetAxisX()) ||
+             GeometryToolbox::IsParallelOrOpposite(isOpposite, normal, slice.GetAxisY()))
+    {
+      // Sagittal or coronal projections
+      
+      return false;
+    }
+    else
+    {
+      return false;
+    }
+  }
 }

--- a/Framework/Toolbox/DicomStructureSet.h	Sun Oct 08 10:52:24 2017 +0200
+++ b/Framework/Toolbox/DicomStructureSet.h	Wed Nov 08 16:13:55 2017 +0100
@@ -22,7 +22,6 @@
 #pragma once
 
 #include "CoordinateSystem3D.h"
-#include "../Viewport/CairoContext.h"
 
 #include <Plugins/Samples/Common/FullOrthancDataset.h>
 
@@ -32,6 +31,9 @@
 {
   class DicomStructureSet : public boost::noncopyable
   {
+  public:
+    typedef std::pair<double, double> PolygonPoint;
+    
   private:
     struct ReferencedSlice
     {
@@ -112,6 +114,12 @@
 
     const Structure& GetStructure(size_t index) const;
 
+    Structure& GetStructure(size_t index);
+  
+    bool ProjectStructure(std::vector< std::vector<PolygonPoint> >& polygons,
+                          Structure& structure,
+                          const CoordinateSystem3D& slice);
+
   public:
     DicomStructureSet(const OrthancPlugins::FullOrthancDataset& instance);
 
@@ -142,12 +150,16 @@
 
     void CheckReferencedSlices();
 
-    void Render(CairoContext& context,
-                const CoordinateSystem3D& slice);
-
     Vector GetNormal() const;
 
     static DicomStructureSet* SynchronousLoad(OrthancPlugins::IOrthancConnection& orthanc,
                                               const std::string& instanceId);
+
+    bool ProjectStructure(std::vector< std::vector<PolygonPoint> >& polygons,
+                          size_t index,
+                          const CoordinateSystem3D& slice)
+    {
+      return ProjectStructure(polygons, GetStructure(index), slice);
+    }
   };
 }