Merge pull request #16 from kenohori/cgal

Validation code to catch more cases of invalid objects

src/ifcgeom/kernels/cgal/CgalConversionFunctions.cpp

@@ -26,7 +26,7 @@ CGAL::Polyhedron_3<Kernel> IfcGeom::CgalKernel::create_polyhedron(std::list<cgal
   //  std::cout << "Before: " << polyhedron.size_of_vertices() << " vertices and " << polyhedron.size_of_facets() << " facets" << std::endl;
   CGAL::Polygon_mesh_processing::stitch_borders(polyhedron);
   if (!polyhedron.is_valid()) {
-    std::cout << "create_polyhedron: Polyhedron not valid!" << std::endl;
+    Logger::Message(Logger::LOG_ERROR, "create_polyhedron: Polyhedron not valid!");
     //    std::ofstream fresult;
     //    fresult.open("/Users/ken/Desktop/invalid.off");
     //    fresult << polyhedron << std::endl;
@@ -50,26 +50,66 @@ CGAL::Polyhedron_3<Kernel> IfcGeom::CgalKernel::create_polyhedron(CGAL::Nef_poly
       nef_polyhedron.convert_to_polyhedron(polyhedron);
       return polyhedron;
     } catch (...) {
-      std::cout << "Conversion from Nef to polyhedron failed!" << std::endl;
+      Logger::Message(Logger::LOG_ERROR, "Conversion from Nef to polyhedron failed!");
       return CGAL::Polyhedron_3<Kernel>();
     }
   } else {
-    std::cout << "Nef polyhedron not simple: cannot create polyhedron!" << std::endl;
+    Logger::Message(Logger::LOG_ERROR, "Nef polyhedron not simple: cannot create polyhedron!");
     return CGAL::Polyhedron_3<Kernel>();
   }
 }
 
 CGAL::Nef_polyhedron_3<Kernel> IfcGeom::CgalKernel::create_nef_polyhedron(std::list<cgal_face_t> &face_list) {
   CGAL::Polyhedron_3<Kernel> polyhedron = create_polyhedron(face_list);
-  return CGAL::Nef_polyhedron_3<Kernel>(polyhedron);
+  CGAL::Polygon_mesh_processing::triangulate_faces(polyhedron);
+  CGAL::Nef_polyhedron_3<Kernel> nef_polyhedron;
+  try {
+    nef_polyhedron = CGAL::Nef_polyhedron_3<Kernel>(polyhedron);
+  } catch (...) {
+    Logger::Message(Logger::LOG_ERROR, "Conversion to Nef polyhedron failed!");
+    return nef_polyhedron;
+  } return nef_polyhedron;
 }
 
 CGAL::Nef_polyhedron_3<Kernel> IfcGeom::CgalKernel::create_nef_polyhedron(CGAL::Polyhedron_3<Kernel> &polyhedron) {
   if (polyhedron.is_valid()) {
     CGAL::Polygon_mesh_processing::triangulate_faces(polyhedron);
-    return CGAL::Nef_polyhedron_3<Kernel>(polyhedron);
+    CGAL::Nef_polyhedron_3<Kernel> nef_polyhedron;
+    try {
+      nef_polyhedron = CGAL::Nef_polyhedron_3<Kernel>(polyhedron);
+    } catch (...) {
+      Logger::Message(Logger::LOG_ERROR, "Conversion to Nef polyhedron failed!");
+      return nef_polyhedron;
+    } return nef_polyhedron;
   } else {
-    std::cout << "Polyhedron not valid: cannot create Nef polyhedron!" << std::endl;
+    Logger::Message(Logger::LOG_ERROR, "Polyhedron not valid: cannot create Nef polyhedron!");
     return CGAL::Nef_polyhedron_3<Kernel>();
   }
 }
+
+//CGAL::Polyhedron_3<Kernel> IfcGeom::CgalKernel::triangulate_faces(CGAL::Polyhedron_3<Kernel> &polyhedron) {
+//  std::list<cgal_face_t> face_list;
+//  
+//  for (CGAL::Polyhedron_3<Kernel>::Facet_const_iterator current_facet = polyhedron.facets_begin();
+//       current_facet != polyhedron.facets_end();
+//       ++current_facet) {
+//    
+//    // Triangle
+//    if (current_facet->is_triangle()) {
+//      face_list.push_back(cgal_face_t());
+//      CGAL::Polyhedron_3<Kernel>::Halfedge_around_facet_const_circulator current_halfedge = current_facet->facet_begin();
+//      do {
+//        face_list.back().outer.push_back(current_halfedge->vertex()->point());
+//        ++current_halfedge;
+//      } while (current_halfedge != current_facet->facet_begin());
+//    }
+//    
+//    // Polygon
+//    else {
+//      std::list<Kernel::Point_3> points_in_polygon;
+//      
+//    }
+//  }
+//  
+//  return create_polyhedron(face_list);
+//}

src/ifcgeom/kernels/cgal/CgalConversionResult.cpp

@@ -10,10 +10,19 @@ void IfcGeom::CgalShape::Triangulate(const IfcGeom::IteratorSettings & settings,
     vertex->point() = vertex->point().transform(trsf);
   }
   
-  if (!s.is_valid() || !s.is_closed()) {
+  std::string error_file_path;
+  for (unsigned int error_number = 1; error_number < 1000; ++error_number) {
+    error_file_path = std::string("/Users/ken/Desktop/error/error");
+    error_file_path += std::to_string(error_number);
+    error_file_path += ".off";
+    std::ifstream file_path_test(error_file_path);
+    if (!file_path_test.good()) break;
+  }
+  
+  if (!s.is_valid()) {
     Logger::Message(Logger::LOG_ERROR, "Invalid Polyhedron_3 in object (before triangulation)");
     std::ofstream ferror;
-    ferror.open("/Users/ken/Desktop/error.off");
+    ferror.open(error_file_path);
     ferror << s << std::endl;
     ferror.close();
     return;
@@ -30,10 +39,20 @@ void IfcGeom::CgalShape::Triangulate(const IfcGeom::IteratorSettings & settings,
   std::map<cgal_face_descriptor_t, Kernel::Vector_3> face_normals;
   boost::associative_property_map<std::map<cgal_face_descriptor_t, Kernel::Vector_3>> face_normals_map(face_normals);
   cgal_shape_t s_copy(s);
-  if (!CGAL::Polygon_mesh_processing::triangulate_faces(s) ) {
+  bool success = false;
+  try {
+    success = CGAL::Polygon_mesh_processing::triangulate_faces(s);
+  } catch (...) {
+    Logger::Message(Logger::LOG_ERROR, "Triangulation crashed");
+    std::ofstream ferror;
+    ferror.open(error_file_path);
+    ferror << s << std::endl;
+    ferror.close();
+    return;
+  } if (!success) {
     Logger::Message(Logger::LOG_ERROR, "Triangulation failed");
     std::ofstream ferror;
-    ferror.open("/Users/ken/Desktop/error.off");
+    ferror.open(error_file_path);
     ferror << s << std::endl;
     ferror.close();
     return;
@@ -45,10 +64,10 @@ void IfcGeom::CgalShape::Triangulate(const IfcGeom::IteratorSettings & settings,
 //  fafter << s << std::endl;
 //  fafter.close();
   
-  if (!s.is_valid() || !s.is_closed()) {
+  if (!s.is_valid()) {
     Logger::Message(Logger::LOG_ERROR, "Invalid Polyhedron_3 in object (after triangulation)");
     std::ofstream ferror;
-    ferror.open("/Users/ken/Desktop/error.off");
+    ferror.open(error_file_path);
     ferror << s_copy << std::endl;
     ferror.close();
     return;

src/ifcgeom/kernels/cgal/CgalIfcGeomShapes.cpp

@@ -91,7 +91,12 @@ bool IfcGeom::CgalKernel::convert(const IfcSchema::IfcExtrudedAreaSolid *l, cgal
       hole_top_face.outer.push_back(*vertex+height*dir);
     } face_list.push_back(hole_top_face);
     
-    nef_shape -= create_nef_polyhedron(face_list);
+    try {
+      nef_shape -= create_nef_polyhedron(face_list);
+    } catch (...) {
+      Logger::Message(Logger::LOG_ERROR, "IfcExtrudedAreaSolid: cannot subtract opening for:", l->entity);
+      return false;
+    }
   }
   
   if (has_position) {
@@ -104,7 +109,7 @@ bool IfcGeom::CgalKernel::convert(const IfcSchema::IfcExtrudedAreaSolid *l, cgal
     nef_shape.convert_to_polyhedron(shape);
     return true;
   } catch (...) {
-    std::cout << "IfcExtrudedAreaSolid: cannot convert Nef to polyhedron!" << std::endl;
+    Logger::Message(Logger::LOG_ERROR, "IfcExtrudedAreaSolid: cannot convert Nef to polyhedron for:", l->entity);
     return false;
   }
   
@@ -238,7 +243,12 @@ bool IfcGeom::CgalKernel::convert(const IfcSchema::IfcExtrudedAreaSolidTapered*
 //    f2 << inner_polyhedron << std::endl;
 //    f2.close();
     
-    nef_shape -= create_nef_polyhedron(face_list);
+    try {
+      nef_shape -= create_nef_polyhedron(face_list);
+    } catch (...) {
+      std::cout << "IfcExtrudedAreaSolidTapered: cannot subtract opening for:" << std::endl;
+      return false;
+    }
     
     ++inner_face1;
     ++inner_face2;
@@ -453,14 +463,24 @@ bool IfcGeom::CgalKernel::convert(const IfcSchema::IfcBooleanResult* l, cgal_sha
   if (op == IfcSchema::IfcBooleanOperator::IfcBooleanOperator_DIFFERENCE) {
     
 //    std::cout << "Difference" << std::endl;
-    CGAL::Nef_polyhedron_3<Kernel> nef_result(s1);
-    if (is_halfspace) {
+    CGAL::Nef_polyhedron_3<Kernel> nef_result;
+    try {
+      nef_result = CGAL::Nef_polyhedron_3<Kernel>(s1);
+    } catch (...) {
+      Logger::Message(Logger::LOG_ERROR, "s1: cannot convert to Nef?", operand1->entity);
+      return false;
+    } if (is_halfspace) {
       if (is_plane) nef_result = nef_result.intersection(plane, CGAL::Nef_polyhedron_3<Kernel>::Intersection_mode::CLOSED_HALFSPACE);
     } else {
-      nef_result -= CGAL::Nef_polyhedron_3<Kernel>(s2);
+      CGAL::Nef_polyhedron_3<Kernel> nef_s2;
+      try {
+        nef_s2 = CGAL::Nef_polyhedron_3<Kernel>(s2);
+      } catch (...) {
+        Logger::Message(Logger::LOG_ERROR, "s2: cannot convert to Nef?", operand2->entity);
+      } nef_result -= nef_s2;
     }
     if (!nef_result.is_simple()) {
-      std::cout << "Not simple: " << nef_result.number_of_volumes() << " volumes" << std::endl;
+      Logger::Message(Logger::LOG_ERROR, "s2: not simple?", operand2->entity);
       return false;
     } else {
 //      CGAL::Polyhedron_3<Kernel> result;

src/ifcgeom/kernels/cgal/CgalKernel.cpp

@@ -96,13 +96,6 @@ IfcGeom::NativeElement<double>* IfcGeom::CgalKernel::create_brep_for_representat
 	try {
 		 convert(product->ObjectPlacement(), trsf);
 	} catch (...) {}
-  
-//  std::cout << "trsf" << std::endl;
-//  for (int i = 0; i < 3; ++i) {
-//    for (int j = 0; j < 4; ++j) {
-//      std::cout << trsf.cartesian(i, j) << " ";
-//    } std::cout << std::endl;
-//  }
 
 	// Does the IfcElement have any IfcOpenings?
 	// Note that openings for IfcOpeningElements are not processed
@@ -210,30 +203,9 @@ bool IfcGeom::CgalKernel::convert_openings(const IfcSchema::IfcProduct* entity,
         } catch (...) {}
       }
       
-//      std::cout << "entity_trsf" << std::endl;
-//      for (int i = 0; i < 3; ++i) {
-//        for (int j = 0; j < 4; ++j) {
-//          std::cout << entity_trsf.cartesian(i, j) << " ";
-//        } std::cout << std::endl;
-//      }
-//      
-//      std::cout << "opening_trsf before" << std::endl;
-//      for (int i = 0; i < 3; ++i) {
-//        for (int j = 0; j < 4; ++j) {
-//          std::cout << opening_trsf.cartesian(i, j) << " ";
-//        } std::cout << std::endl;
-//      }
-      
       // Move the opening into the coordinate system of the IfcProduct
       opening_trsf = entity_trsf.inverse() * opening_trsf;
       
-//      std::cout << "opening_trsf after" << std::endl;
-//      for (int i = 0; i < 3; ++i) {
-//        for (int j = 0; j < 4; ++j) {
-//          std::cout << opening_trsf.cartesian(i, j) << " ";
-//        } std::cout << std::endl;
-//      }
-      
       IfcSchema::IfcProductRepresentation* prodrep = fes->Representation();
       IfcSchema::IfcRepresentation::list::ptr reps = prodrep->Representations();
       
@@ -252,13 +224,6 @@ bool IfcGeom::CgalKernel::convert_openings(const IfcSchema::IfcProduct* entity,
         cgal_shape_t opening_shape(((CgalShape*)opening_shapes[i].Shape())->shape());
         for (auto &vertex: vertices(opening_shape)) vertex->point() = vertex->point().transform(gtrsf);
         opening_shapelist.push_back(opening_shape);
-
-//        std::cout << "gtrsf" << std::endl;
-//        for (int i = 0; i < 3; ++i) {
-//          for (int j = 0; j < 4; ++j) {
-//            std::cout << gtrsf.cartesian(i, j) << " ";
-//          } std::cout << std::endl;
-//        }
       }
       
     }
@@ -273,51 +238,183 @@ bool IfcGeom::CgalKernel::convert_openings(const IfcSchema::IfcProduct* entity,
       for (auto &vertex: vertices(entity_shape)) vertex->point() = vertex->point().transform(entity_shape_gtrsf);
     }
     
-    cgal_shape_t brep_cut_result(entity_shape);
-    CGAL::Nef_polyhedron_3<Kernel> nef_brep_cut_result(brep_cut_result);
+    cgal_shape_t original_entity_shape(entity_shape);
+    if (!entity_shape.is_valid()) {
+      Logger::Message(Logger::LOG_ERROR, "Conversion to Nef will fail. Invalid entity:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } if (!entity_shape.is_closed()) {
+      // TODO: There can be substractions to remove parts of non-volumetric objects. Maybe iterate over all faces of an entity and put them in a Nef_polyhedron_3 through Boolean union? Highly inefficient but maybe desirable...
+      Logger::Message(Logger::LOG_ERROR, "Subtraction of openings not supported for non-closed entity:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } bool success = false;
+    try {
+      success = CGAL::Polygon_mesh_processing::triangulate_faces(entity_shape);
+    } catch (...) {
+      Logger::Message(Logger::LOG_ERROR, "Triangulation of entity crashed:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } if (!success) {
+      Logger::Message(Logger::LOG_ERROR, "Triangulation of entity failed:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } if (CGAL::Polygon_mesh_processing::does_self_intersect(entity_shape)) {
+      Logger::Message(Logger::LOG_ERROR, "Conversion to Nef will fail. Self-intersecting entity:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } CGAL::Nef_polyhedron_3<Kernel> nef_brep_cut_result;
+    try {
+      nef_brep_cut_result = CGAL::Nef_polyhedron_3<Kernel>(entity_shape);
+    } catch (...) {
+      Logger::Message(Logger::LOG_ERROR, "Could not convert entity to Nef:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } try {
+      cgal_shape_t brep_cut_result;
+      nef_brep_cut_result.convert_to_polyhedron(brep_cut_result);
+    } catch (...) {
+      Logger::Message(Logger::LOG_WARNING, "Final conversion will likely fail. Could not convert entity from Nef:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+//      return false;
+    }
     
     for (auto &opening: opening_shapelist) {
       
-//      CGAL::Polyhedron_3<Kernel> polyhedron;
-//      brep_cut_result.convert_to_polyhedron(polyhedron);
-//      std::ofstream fresult;
-//      fresult.open("/Users/ken/Desktop/before.off");
-//      fresult << polyhedron << std::endl;
-//      fresult.close();
-//      
-//      opening.convert_to_polyhedron(polyhedron);
-//      fresult.open("/Users/ken/Desktop/opening.off");
-//      fresult << polyhedron << std::endl;
-//      fresult.close();
-      
-      CGAL::Nef_polyhedron_3<Kernel> nef_opening(opening);
-      nef_brep_cut_result -= nef_opening;
-      
-//      brep_cut_result.convert_to_polyhedron(polyhedron);
-//      fresult.open("/Users/ken/Desktop/after.off");
-//      fresult << polyhedron << std::endl;
-//      fresult.close();
-    }
-    
-    if (brep_cut_result.is_valid()) {
+      cgal_shape_t original_opening_shape(opening);
+      if (!opening.is_valid()) {
+        Logger::Message(Logger::LOG_ERROR, "Conversion to Nef will fail. Invalid opening in entity:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+        return false;
+      } if (!opening.is_closed()) {
+        Logger::Message(Logger::LOG_ERROR, "Subtraction of opening makes no sense. Not closed opening in entity:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+        return false;
+      } success = false;
       try {
-        nef_brep_cut_result.convert_to_polyhedron(brep_cut_result);
-        cut_shapes.push_back(IfcGeom::ConversionResult(new CgalShape(brep_cut_result), &it3->Style()));
+        success = CGAL::Polygon_mesh_processing::triangulate_faces(opening);
       } catch (...) {
-        // Apparently processing the boolean operation failed or resulted in an invalid result
-        // in which case the original shape without the subtractions is returned instead
-        // we try convert the openings in the original way, one by one.
-        Logger::Message(Logger::LOG_WARNING, "Subtracting combined openings compound failed:", entity->entity);
+        Logger::Message(Logger::LOG_ERROR, "Triangulation of opening of entity crashed:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+        return false;
+      } if (!success) {
+        Logger::Message(Logger::LOG_ERROR, "Triangulation of opening of entity failed:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+        return false;
+      } if (CGAL::Polygon_mesh_processing::does_self_intersect(entity_shape)) {
+        Logger::Message(Logger::LOG_ERROR, "Conversion to Nef will fail. Self-intersecting opening of entity:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+        return false;
+      } CGAL::Nef_polyhedron_3<Kernel> nef_opening;
+      try {
+        nef_opening = CGAL::Nef_polyhedron_3<Kernel>(opening);
+      } catch (...) {
+        Logger::Message(Logger::LOG_ERROR, "Could not convert opening of entity to Nef:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+        return false;
+      } try {
+        cgal_shape_t opening_shape;
+        nef_opening.convert_to_polyhedron(opening_shape);
+      } catch (...) {
+        Logger::Message(Logger::LOG_WARNING, "Final conversion will likely fail. Could not convert opening of entity from Nef:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
+//        return false;
+      } try {
+        nef_brep_cut_result -= nef_opening;
+      } catch (...) {
+        Logger::Message(Logger::LOG_ERROR, "Could not subtract Nef opening of entity:", entity->entity);
+        std::ofstream fentity;
+        fentity.open("/Users/ken/Desktop/entity.off");
+        fentity << original_entity_shape << std::endl;
+        fentity.close();
+        std::ofstream fopening;
+        fopening.open("/Users/ken/Desktop/opening.off");
+        fopening << original_opening_shape << std::endl;
+        fopening.close();
         return false;
       }
-    } else {
-      // Apparently processing the boolean operation failed or resulted in an invalid result
-      // in which case the original shape without the subtractions is returned instead
-      // we try convert the openings in the original way, one by one.
-      Logger::Message(Logger::LOG_WARNING, "Subtracting combined openings compound failed:", entity->entity);
-      return false;
     }
     
-  }
-  return true;
+    try {
+      nef_brep_cut_result.convert_to_polyhedron(entity_shape);
+    } catch (...) {
+      Logger::Message(Logger::LOG_ERROR, "Could not convert entity with openings from Nef:", entity->entity);
+      std::ofstream fentity;
+      fentity.open("/Users/ken/Desktop/entity.off");
+      fentity << original_entity_shape << std::endl;
+      fentity.close();
+      return false;
+    } cut_shapes.push_back(IfcGeom::ConversionResult(new CgalShape(entity_shape), &it3->Style()));
+    
+  } return true;
 }

src/ifcgeom/kernels/cgal/CgalKernel.h

@@ -47,6 +47,7 @@ if ( it != cache.T.end() ) { e = it->second; return true; }
 #include <CGAL/Polygon_mesh_processing/orientation.h>
 #include <CGAL/Polygon_mesh_processing/triangulate_faces.h>
 #include <CGAL/Polygon_mesh_processing/compute_normal.h>
+#include <CGAL/Polygon_mesh_processing/self_intersections.h>
 #include <CGAL/Nef_polyhedron_3.h>
 
 typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;
@@ -140,6 +141,7 @@ namespace IfcGeom {
 
     bool convert_openings(const IfcSchema::IfcProduct* entity, const IfcSchema::IfcRelVoidsElement::list::ptr& openings, const ConversionResults& entity_shapes, const cgal_placement_t& entity_trsf, ConversionResults& cut_shapes);
     
+//    CGAL::Polyhedron_3<Kernel> triangulate_faces(CGAL::Polyhedron_3<Kernel> &polyhedron);
     CGAL::Polyhedron_3<Kernel> create_polyhedron(std::list<cgal_face_t> &face_list);
     CGAL::Polyhedron_3<Kernel> create_polyhedron(CGAL::Nef_polyhedron_3<Kernel> &nef_polyhedron);
     CGAL::Nef_polyhedron_3<Kernel> create_nef_polyhedron(std::list<cgal_face_t> &face_list);