Merge branch 'occ_properties' into 'master'

load/store occ geometry properties (maxh, hpref, color opacity)

See merge request jschoeberl/netgen!443

libsrc/occ/occgenmesh.cpp

@@ -408,29 +408,11 @@ namespace netgen
 
         mesh.AddFaceDescriptor (FaceDescriptor(facenr, solidnr0, solidnr1, 0));
 
-        // Philippose - 06/07/2009
+        Vec<4> col = OCCGeometry::global_shape_properties[face.TShape()].col.value_or(Vec<4>(0,1,0,1));
-        // Add the face colour to the mesh data
+        mesh.GetFaceDescriptor(facenr).SetSurfColour(col);
-        Quantity_Color face_colour;
 
-        if(!(geom.face_colours.IsNull())
+        if(auto opt_name = geom.fprops[facenr-1]->name) 
-           && (geom.face_colours->GetColor(face,XCAFDoc_ColorSurf,face_colour)))
+          mesh.GetFaceDescriptor(facenr).SetBCName(&*opt_name);
-          {
-            mesh.GetFaceDescriptor(facenr).SetSurfColour({face_colour.Red(),face_colour.Green(),face_colour.Blue()});
-          }
-        else
-          {
-            auto it = OCCGeometry::global_shape_properties.find(face.TShape());
-            if (it != OCCGeometry::global_shape_properties.end() && it->second.col)
-              {
-                Vec<4> col = it->second.col.value_or(Vec<4>(0,1,0,1));
-                mesh.GetFaceDescriptor(facenr).SetSurfColour(col);                
-              }
-            else
-              mesh.GetFaceDescriptor(facenr).SetSurfColour({0.0,1.0,0.0});
-          }
-
-        if(geom.fnames.Size()>=facenr) 
-          mesh.GetFaceDescriptor(facenr).SetBCName(&geom.fnames[facenr-1]);
         mesh.GetFaceDescriptor(facenr).SetBCProperty(facenr);
         // ACHTUNG! STIMMT NICHT ALLGEMEIN (RG)
 
@@ -602,7 +584,7 @@ namespace netgen
                     alledgeparams[geomedgenr-1] = params;
                   }
 
-                auto name = geom.enames.Size() ? geom.enames[geom.emap.FindIndex(edge)-1] : "";
+                auto name = geom.eprops[geom.emap.FindIndex(edge)-1]->name.value_or("");
                 mesh.SetCD2Name(geomedgenr, name);
                   
                 (*testout) << "NP = " << mesh.GetNP() << endl;

libsrc/occ/occgeom.cpp

@@ -30,6 +30,16 @@
 #include <Standard_Version.hxx>
 #endif
 
+#include <STEPConstruct.hxx>
+#include <Transfer_FinderProcess.hxx>
+#include <TDataStd_Name.hxx>
+#include <XCAFPrs.hxx>
+#include <TopoDS_Shape.hxx>
+#include <XCAFPrs_Style.hxx>
+#include <TopTools_ShapeMapHasher.hxx>
+#include <NCollection_IndexedDataMap.hxx>
+#include <StepShape_TopologicalRepresentationItem.hxx>
+
 #if OCC_VERSION_HEX < 0x070000
 // pass
 #elif OCC_VERSION_HEX < 0x070200
@@ -41,47 +51,18 @@
 
 namespace netgen
 {
+  void LoadOCCInto(OCCGeometry* occgeo, const char* filename);
 
-  // std::map<Handle(TopoDS_TShape), string> OCCGeometry::global_shape_names;
-  // std::map<Handle(TopoDS_TShape), Vec<3>> OCCGeometry::global_shape_cols;
   std::map<Handle(TopoDS_TShape), ShapeProperties> OCCGeometry::global_shape_properties;
   std::map<Handle(TopoDS_TShape), std::vector<OCCIdentification>> OCCGeometry::identifications;
   
   OCCGeometry::OCCGeometry(const TopoDS_Shape& _shape, int aoccdim)
   {
-    shape = _shape;
+    auto filename = ".tmpfile_out.step";
+    step_utils::WriteSTEP(_shape, filename);
+    LoadOCCInto(this, filename);
     occdim = aoccdim;
-    changed = true;
+    std::remove(filename);
-    BuildFMap();
-    CalcBoundingBox();
-
-    snames.SetSize(somap.Size());
-    for(auto i : Range(snames))
-      snames[i] = "domain_" + ToString(i+1);
-    for (TopExp_Explorer e(shape, TopAbs_SOLID); e.More(); e.Next())
-      {
-         TopoDS_Solid solid = TopoDS::Solid(e.Current());
-         if (auto name = global_shape_properties[solid.TShape()].name)
-           snames[somap.FindIndex(solid)-1] = *name;
-      }
-
-    fnames.SetSize(fmap.Size());
-    for(auto i : Range(fnames))
-      fnames[i] = "bc_" + ToString(i+1);
-    for(TopExp_Explorer e(shape, TopAbs_FACE); e.More(); e.Next())
-      {
-         TopoDS_Face face = TopoDS::Face(e.Current());
-         if (auto name = global_shape_properties[face.TShape()].name)
-           fnames[fmap.FindIndex(face)-1] = *name;
-      }
-    enames.SetSize(emap.Size());
-    enames = "";
-    for (TopExp_Explorer e(shape, TopAbs_EDGE); e.More(); e.Next())
-      {
-        TopoDS_Edge edge = TopoDS::Edge(e.Current());
-        if (auto name = global_shape_properties[edge.TShape()].name)
-          enames[emap.FindIndex(edge)-1] = *name;
-      }
   }
 
   string STEP_GetEntityName(const TopoDS_Shape & theShape, STEPCAFControl_Reader * aReader)
@@ -138,8 +119,8 @@ namespace netgen
   void OCCGeometry :: FinalizeMesh(Mesh& mesh) const
   {
     for (int i = 0; i < mesh.GetNDomains(); i++)
-      if (snames.Size())
+      if (auto name = sprops[i]->name)
-        mesh.SetMaterial (i+1, snames[i]);
+        mesh.SetMaterial (i+1, *name);
   }
 
    void OCCGeometry :: PrintNrShapes ()
@@ -364,22 +345,10 @@ namespace netgen
          Handle(ShapeBuild_ReShape) rebuild = new ShapeBuild_ReShape;
          rebuild->Apply(shape);
 
-
          for (exp0.Init (shape, TopAbs_FACE); exp0.More(); exp0.Next())
          {
-            // Variable to hold the colour (if there exists one) of 
-            // the current face being processed
-            Quantity_Color face_colour;
-
             TopoDS_Face face = TopoDS::Face (exp0.Current());
-
+            auto props = global_shape_properties[face.TShape()];
-            if(face_colours.IsNull()
-               || (!(face_colours->GetColor(face,XCAFDoc_ColorSurf,face_colour))))
-            {
-               // Set the default face colour to green (Netgen Standard)
-               // if no colour has been defined for the face
-               face_colour = Quantity_Color(0.0,1.0,0.0,Quantity_TOC_RGB);
-            }
 
             sff = new ShapeFix_Face (face);
             sff->FixAddNaturalBoundMode() = Standard_True;
@@ -408,11 +377,9 @@ namespace netgen
                rebuild->Replace(face, newface);
             }
 
-            // Set the original colour of the face to the newly created 
+            // Set the original properties of the face to the newly created 
             // face (after the healing process)
-            face = TopoDS::Face (exp0.Current());
+            global_shape_properties[face.TShape()];
-            if(face_colours)
-              face_colours->SetColor(face,face_colour,XCAFDoc_ColorSurf);
          }
          shape = rebuild->Apply(shape);
       }
@@ -1054,6 +1021,28 @@ namespace netgen
       vsingular.SetSize (vmap.Extent());
 
       fsingular = esingular = vsingular = false;
+
+
+      sprops.SetSize(somap.Extent());
+      for (TopExp_Explorer e(shape, TopAbs_SOLID); e.More(); e.Next())
+      {
+          auto s = e.Current();
+          sprops[somap.FindIndex(s)-1] = &global_shape_properties[s.TShape()];
+      }
+
+      fprops.SetSize(fmap.Extent());
+      for (TopExp_Explorer e(shape, TopAbs_FACE); e.More(); e.Next())
+      {
+          auto s = e.Current();
+          fprops[fmap.FindIndex(s)-1] = &global_shape_properties[s.TShape()];
+      }
+
+      eprops.SetSize(emap.Extent());
+      for (TopExp_Explorer e(shape, TopAbs_EDGE); e.More(); e.Next())
+      {
+          auto s = e.Current();
+          eprops[emap.FindIndex(s)-1] = &global_shape_properties[s.TShape()];
+      }
    }
 
 
@@ -1491,127 +1480,22 @@ namespace netgen
       timer_transfer.Stop();
 
       // Read in the shape(s) and the colours present in the STEP File
-      Handle(XCAFDoc_ShapeTool) step_shape_contents = XCAFDoc_DocumentTool::ShapeTool(step_doc->Main());
+      auto step_shape_contents = XCAFDoc_DocumentTool::ShapeTool(step_doc->Main());
-      Handle(XCAFDoc_ColorTool) step_colour_contents = XCAFDoc_DocumentTool::ColorTool(step_doc->Main());
 
       TDF_LabelSequence step_shapes;
       step_shape_contents->GetShapes(step_shapes);
 
-      // List out the available colours in the STEP File as Colour Names
-      TDF_LabelSequence all_colours;
-      step_colour_contents->GetColors(all_colours);
-      PrintMessage(1,"Number of colours in STEP File: ",all_colours.Length());
-      for(int i = 1; i <= all_colours.Length(); i++)
-      {
-         Quantity_Color col;
-         stringstream col_rgb;
-         step_colour_contents->GetColor(all_colours.Value(i),col);
-         col_rgb << " : (" << col.Red() << "," << col.Green() << "," << col.Blue() << ")";
-         PrintMessage(1, "Colour [", i, "] = ",col.StringName(col.Name()),col_rgb.str());
-      }
-
-
       // For the STEP File Reader in OCC, the 1st Shape contains the entire 
       // compound geometry as one shape
-      occgeo->shape = step_shape_contents->GetShape(step_shapes.Value(1));
+      auto main_shape = step_shape_contents->GetShape(step_shapes.Value(1)); 
-      occgeo->face_colours = step_colour_contents;
+
+      step_utils::LoadProperties(main_shape, reader, step_doc);
+
+      occgeo->shape = main_shape;
       occgeo->changed = 1;
       occgeo->BuildFMap();
-
       occgeo->CalcBoundingBox();
       PrintContents (occgeo);
-      string name;
-      TopExp_Explorer exp0,exp1;
-
-      
-      
-      std::map<Handle(TopoDS_TShape), string> shape_names;
-      {
-        static Timer t("file shape_names"); RegionTimer r(t);
-        // code inspired from 
-        // https://www.opencascade.com/content/reading-step-entity-id-slow
-        const Handle(XSControl_WorkSession) workSession = reader.Reader().WS();
-        const Handle(Interface_InterfaceModel) model = workSession->Model();
-        const Handle(XSControl_TransferReader) transferReader = workSession->TransferReader();
-        Handle(Transfer_TransientProcess) transProc = transferReader->TransientProcess();
-
-        Standard_Integer nb = model->NbEntities();
-        for (Standard_Integer i = 1; i < nb; i++)
-          {
-            Handle(Standard_Transient) entity = model->Value(i);
-            
-            // if (!entity->DynamicType()->SubType("StepShape_OpenShell")) continue;
-            
-            Handle(StepRepr_RepresentationItem) SRRI =
-              Handle(StepRepr_RepresentationItem)::DownCast(entity);
-            
-            if (SRRI.IsNull()) {
-              // cout << "no StepRepr_RepresentationItem found in " << entity->DynamicType()->Name();
-              continue;
-            }
-            Handle(TCollection_HAsciiString) hName = SRRI->Name();
-            string shapeName = hName->ToCString();
-            
-            // cout << "STEP " << i << " " << entity->DynamicType()->Name() << ", shapename = " << shapeName;
-            Handle(Transfer_Binder) binder;
-            if (!transProc->IsBound(SRRI)) {
-              // cout << "found unbound entity " << shapeName;
-              continue;
-            }
-            binder = transProc->Find(SRRI);
-            TopoDS_Shape shape = TransferBRep::ShapeResult(binder);
-            // if (!shape.IsNull())
-            shape_names[shape.TShape()] = shapeName;
-            /*
-            if (!shape.IsNull())
-              cout << " shapetype = " << shape.ShapeType() << endl;
-            else
-              cout << "is-Null" << endl;
-            */
-          }
-        // for (auto pair : shape_names)
-        // cout << "name = " << pair.second << endl;
-      }
-
-      for (auto [s,n] : shape_names)
-        OCCGeometry::global_shape_properties[s].name = n;
-      
-      
-      timer_getnames.Start();
-      occgeo->snames.SetSize(occgeo->somap.Size());
-      for (exp0.Init(occgeo->shape, TopAbs_SOLID); exp0.More(); exp0.Next())
-      {
-         TopoDS_Solid solid = TopoDS::Solid(exp0.Current());
-         // name = STEP_GetEntityName(solid,&reader);
-         // cout << "solidname = " << name << ", mapname = " << shape_names[solid.TShape()] << endl;         
-         name = shape_names[solid.TShape()];
-         if (name == "")
-           name = string("domain_") + ToString(occgeo->snames.Size());
-         occgeo->snames[occgeo->somap.FindIndex(solid)-1] = name;
-      }
-
-      occgeo->fnames.SetSize(occgeo->fmap.Size());
-      occgeo->enames.SetSize(occgeo->emap.Size());
-      for (exp0.Init(occgeo->shape, TopAbs_FACE); exp0.More(); exp0.Next())
-      {
-         TopoDS_Face face = TopoDS::Face(exp0.Current());
-         // name = STEP_GetEntityName(face,&reader);
-         // cout << "getname = " << name << ", mapname = " << shape_names[face.TShape()] << endl;
-         name = shape_names[face.TShape()];
-         auto index = occgeo->fmap.FindIndex(face);
-         if (name == "")
-           name = string("bc_") + ToString(index);
-         occgeo->fnames[index-1] = name;
-         for (exp1.Init(face, TopAbs_EDGE); exp1.More(); exp1.Next())
-           {
-             TopoDS_Edge edge = TopoDS::Edge(exp1.Current());
-             // name = STEP_GetEntityName(edge,&reader);
-             // cout << "getname = " << name << ", mapname = " << shape_names[edge.TShape()] << endl;
-             name = shape_names[edge.TShape()];
-             occgeo->enames[occgeo->emap.FindIndex(edge)-1] = name;
-           }
-      }
-      timer_getnames.Stop();      
   }
 
    // Philippose - 23/02/2009
@@ -1676,7 +1560,6 @@ namespace netgen
       // For the IGES Reader, all the shapes can be exported as one compound shape
       // using the "OneShape" member
       occgeo->shape = reader.OneShape();
-      occgeo->face_colours = iges_colour_contents;
       occgeo->changed = 1;
       occgeo->BuildFMap();
 
@@ -1720,12 +1603,6 @@ namespace netgen
          return NULL;
       }
 
-      // Philippose - 23/02/2009
-      // Fixed a bug in the OpenCascade XDE Colour handling when 
-      // opening BREP Files, since BREP Files have no colour data.
-      // Hence, the face_colours Handle needs to be created as a NULL handle.
-      occgeo->face_colours = Handle(XCAFDoc_ColorTool)();
-      occgeo->face_colours.Nullify();
       occgeo->changed = 1;
       occgeo->BuildFMap();
 
@@ -1750,9 +1627,7 @@ namespace netgen
       }
     else if (strcmp (&filename[strlen(filename)-3], "stp") == 0)
       {
-	STEPControl_Writer writer;
+          step_utils::WriteSTEP(*this, filename);
-	writer.Transfer (shape, STEPControl_AsIs);
-	writer.Write (filename);
       }
     else if (strcmp (&filename[strlen(filename)-3], "stl") == 0)
       {
@@ -2105,6 +1980,169 @@ namespace netgen
   //    return OCCGenerateMesh (*this, mesh, mparam, occparam);
   //  }
   static RegisterClassForArchive<OCCGeometry, NetgenGeometry> regnggeo;
+
+  namespace step_utils
+  {
+      void LoadProperties(const TopoDS_Shape & shape,
+                          const STEPCAFControl_Reader & reader,
+                          const Handle(TDocStd_Document) step_doc)
+      {
+        static Timer t("step_utils::LoadProperties"); RegionTimer rt(t);
+
+        auto workSession = reader.Reader().WS();
+        auto model = workSession->Model();
+        auto transferReader = workSession->TransferReader();
+        auto transProc = transferReader->TransientProcess();
+        auto shapeTool = XCAFDoc_DocumentTool::ShapeTool(step_doc->Main());
+
+        // load colors
+        for (auto typ : { TopAbs_SOLID, TopAbs_FACE,  TopAbs_EDGE })
+          for (TopExp_Explorer e(shape, typ); e.More(); e.Next())
+          {
+            TDF_Label label;
+            shapeTool->Search(e.Current(), label);
+
+            if(label.IsNull())
+                continue;
+
+            XCAFPrs_IndexedDataMapOfShapeStyle set;
+            TopLoc_Location loc;
+            XCAFPrs::CollectStyleSettings(label, loc, set);
+            XCAFPrs_Style aStyle;
+            set.FindFromKey(e.Current(), aStyle);
+
+            auto & prop = OCCGeometry::global_shape_properties[e.Current().TShape()];
+            if(aStyle.IsSetColorSurf())
+                prop.col = step_utils::ReadColor(aStyle.GetColorSurfRGBA());
+          }
+
+        // load names
+        Standard_Integer nb = model->NbEntities();
+        for (Standard_Integer i = 1; i < nb; i++)
+          {
+            Handle(Standard_Transient) entity = model->Value(i);
+            auto item = Handle(StepRepr_RepresentationItem)::DownCast(entity);
+
+            if(item.IsNull())
+                continue;
+
+            TopoDS_Shape shape = TransferBRep::ShapeResult(transProc->Find(item));
+            string name = item->Name()->ToCString();
+            if (!transProc->IsBound(item))
+              continue;
+
+            OCCGeometry::global_shape_properties[shape.TShape()].name = name;
+          }
+
+
+        // load custom data (maxh etc.)
+        for (Standard_Integer i = 1; i < nb; i++)
+          {
+            Handle(Standard_Transient) entity = model->Value(i);
+
+            auto item = Handle(StepRepr_CompoundRepresentationItem)::DownCast(entity);
+
+            if(item.IsNull())
+                continue;
+
+            string name = item->Name()->ToCString();
+            if(name != "netgen_geometry_properties")
+                continue;
+
+            auto shape_item = item->ItemElementValue(1);
+            Handle(Transfer_Binder) binder;
+            binder = transProc->Find(shape_item);
+            TopoDS_Shape shape = TransferBRep::ShapeResult(binder);
+            auto & prop = OCCGeometry::global_shape_properties[shape.TShape()];
+
+            auto nprops = item->NbItemElement();
+
+            for(auto i : Range(2, nprops+1))
+            {
+                auto prop_item = item->ItemElementValue(i);
+                string prop_name = prop_item->Name()->ToCString();
+
+                if(prop_name=="maxh")
+                    prop.maxh = Handle(StepRepr_ValueRepresentationItem)::DownCast(prop_item)
+                        ->ValueComponentMember()->Real();
+
+                if(prop_name=="hpref")
+                    prop.hpref = Handle(StepRepr_ValueRepresentationItem)::DownCast(prop_item)
+                        ->ValueComponentMember()->Real();
+            }
+          }
+      }
+
+      void WriteProperties(const Handle(Interface_InterfaceModel) model, const Handle(Transfer_FinderProcess) finder, const TopoDS_Shape & shape)
+      {
+          static const ShapeProperties default_props;
+          Handle(StepRepr_RepresentationItem) item = STEPConstruct::FindEntity(finder, shape);
+          if(!item)
+              return;
+          auto prop = OCCGeometry::global_shape_properties[shape.TShape()];
+
+          if(auto n = prop.name)
+              item->SetName(MakeName(*n));
+
+          Array<Handle(StepRepr_RepresentationItem)> props;
+          props.Append(item);
+
+          if(auto maxh = prop.maxh; maxh != default_props.maxh)
+              props.Append( MakeReal(maxh, "maxh") );
+
+          if(auto hpref = prop.hpref; hpref != default_props.hpref)
+              props.Append( MakeReal(hpref, "hpref") );
+
+          if(props.Size()==1)
+              return;
+
+          for(auto & item : props.Range(1, props.Size()))
+              model->AddEntity(item);
+
+          auto compound = MakeCompound(props, "netgen_geometry_properties");
+          model->AddEntity(compound);
+      }
+
+      void WriteSTEP(const TopoDS_Shape & shape, string filename)
+      {
+          Interface_Static::SetCVal("write.step.schema", "AP242IS");
+          Interface_Static::SetIVal("write.step.assembly",1);
+          Handle(XCAFApp_Application) app = XCAFApp_Application::GetApplication();
+          Handle(TDocStd_Document) doc;
+
+          app->NewDocument("STEP-XCAF", doc);
+          Handle(XCAFDoc_ShapeTool) shapetool = XCAFDoc_DocumentTool::ShapeTool(doc->Main());
+          Handle(XCAFDoc_ColorTool) colortool = XCAFDoc_DocumentTool::ColorTool(doc->Main());
+          TDF_Label label = shapetool->NewShape();
+          shapetool->SetShape(label, shape);
+
+          Handle(XSControl_WorkSession) session = new XSControl_WorkSession;
+          STEPCAFControl_Writer writer(session);
+          const Handle(Interface_InterfaceModel) model = session->Model();
+
+          // Set colors (BEFORE transferring shape into step data structures)
+          for (auto typ : { TopAbs_SOLID, TopAbs_FACE,  TopAbs_EDGE })
+            for (TopExp_Explorer e(shape, typ); e.More(); e.Next())
+              {
+                auto prop = OCCGeometry::global_shape_properties[e.Current().TShape()];
+                if(auto col = prop.col)
+                    colortool->SetColor(e.Current(), step_utils::MakeColor(*col), XCAFDoc_ColorGen);
+              }
+
+          // Transfer shape into step data structures -> now we can manipulate/add step representation items
+          writer.Transfer(doc, STEPControl_AsIs);
+
+          // Write all other properties
+          auto finder = session->TransferWriter()->FinderProcess();
+
+          for (auto typ : { TopAbs_SOLID, TopAbs_FACE,  TopAbs_EDGE })
+            for (TopExp_Explorer e(shape, typ); e.More(); e.Next())
+                WriteProperties(model, finder, e.Current());
+
+          writer.Write(filename.c_str());
+      }
+
+  } // namespace step_utils
 }
 
 

libsrc/occ/occgeom.hpp

@@ -85,6 +85,11 @@
 #include "IGESControl_Writer.hxx"
 #include "STEPControl_Writer.hxx"
 
+#include <StepRepr_ValueRepresentationItem.hxx>
+#include <StepRepr_IntegerRepresentationItem.hxx>
+#include <StepRepr_CompoundRepresentationItem.hxx>
+#include <StepBasic_MeasureValueMember.hxx>
+
 #include "StlAPI_Writer.hxx"
 #include "STEPControl_StepModelType.hxx"
 
@@ -229,6 +234,7 @@ namespace netgen
     }
   };
 
+
   class OCCIdentification
   {
   public:
@@ -245,20 +251,13 @@ namespace netgen
   public:
     static std::map<Handle(TopoDS_TShape), ShapeProperties> global_shape_properties;
     static std::map<Handle(TopoDS_TShape), std::vector<OCCIdentification>> identifications;
-    // static std::map<Handle(TopoDS_TShape), string> global_shape_names;
+
-    // static std::map<Handle(TopoDS_TShape), Vec<3>> global_shape_cols;
-    
     TopoDS_Shape shape;
     TopTools_IndexedMapOfShape fmap, emap, vmap, somap, shmap, wmap;
     NgArray<bool> fsingular, esingular, vsingular;
     Box<3> boundingbox;
-    NgArray<string> fnames, enames, snames;
+    Array<ShapeProperties*> fprops, eprops, sprops; // pointers to the gobal property map
-    // Philippose - 29/01/2009
+
-    // OpenCascade XDE Support
-    // XCAF Handle to make the face colours available to the rest of
-    // the system
-    Handle(XCAFDoc_ColorTool) face_colours;
-     
     mutable int changed;
     mutable NgArray<int> facemeshstatus;
 
@@ -505,6 +504,70 @@ namespace netgen
   DLL_HEADER extern void OCCOptimizeSurface (OCCGeometry & geom, Mesh & mesh, const MeshingParameters & mparam);
 
   DLL_HEADER extern void OCCFindEdges (const OCCGeometry & geom, Mesh & mesh, const MeshingParameters & mparam);
+
+
+  namespace step_utils
+  {
+      inline Handle(TCollection_HAsciiString) MakeName (string s)
+      {
+          return new TCollection_HAsciiString(s.c_str());
+      };
+
+      inline Handle(StepRepr_RepresentationItem) MakeInt (int n, string name = "")
+      {
+          Handle(StepRepr_IntegerRepresentationItem) int_obj = new StepRepr_IntegerRepresentationItem;
+          int_obj->Init(MakeName(name), n);
+          return int_obj;
+      }
+
+      inline Handle(StepRepr_RepresentationItem) MakeReal (double val, string name = "")
+      {
+            Handle(StepBasic_MeasureValueMember) value_member = new StepBasic_MeasureValueMember;
+            value_member->SetReal(val);
+            Handle(StepRepr_ValueRepresentationItem) value_repr = new StepRepr_ValueRepresentationItem;
+            value_repr->Init(MakeName(name), value_member);
+            return value_repr;
+      }
+
+      inline Handle(StepRepr_RepresentationItem) MakeCompound( FlatArray<Handle(StepRepr_RepresentationItem)> items, string name = "" )
+      {
+            Handle(StepRepr_HArray1OfRepresentationItem) array_repr = new StepRepr_HArray1OfRepresentationItem(1,items.Size());
+
+            for(auto i : Range(items))
+                array_repr->SetValue(i+1, items[i]);
+
+            Handle(StepRepr_CompoundRepresentationItem) comp = new StepRepr_CompoundRepresentationItem;
+            comp->Init( MakeName(name), array_repr );
+            return comp;
+      }
+
+      inline Quantity_ColorRGBA MakeColor(const Vec<4> & c)
+      {
+          return Quantity_ColorRGBA (c[0], c[1], c[2], c[3]);
+      }
+
+      inline Vec<4> ReadColor (const Quantity_ColorRGBA & c)
+      {
+          auto rgb = c.GetRGB();
+          return {rgb.Red(), rgb.Green(), rgb.Blue(), c.Alpha()};
+      }
+
+
+      void LoadProperties(const TopoDS_Shape & shape,
+                          const STEPCAFControl_Reader & reader,
+                          const Handle(TDocStd_Document) step_doc);
+      void WriteProperties(const Handle(Interface_InterfaceModel) model, const Handle(Transfer_FinderProcess) finder, const TopoDS_Shape & shape);
+
+      void WriteSTEP(const TopoDS_Shape & shape, string filename);
+
+      inline void WriteSTEP(const OCCGeometry & geo, string filename)
+      {
+          WriteSTEP(geo.GetShape(), filename);
+      }
+
+      // deep copy, also ensures consistent shape ordering (face numbers etc.)
+      TopoDS_Shape WriteAndRead(const TopoDS_Shape shape);
+  } // namespace step_utils
 }
 
 #endif

libsrc/occ/python_occ_shapes.cpp

@@ -27,6 +27,8 @@
 #include <BRepAlgoAPI_Fuse.hxx>
 // #include <XCAFDoc_VisMaterialTool.hxx>
 #include <TDF_Attribute.hxx>
+#include <TDataStd_Real.hxx>
+#include <TDataStd_Name.hxx>
 #include <Standard_GUID.hxx>
 #include <Geom_TrimmedCurve.hxx>
 #include <Geom_Plane.hxx>
@@ -836,14 +838,9 @@ DLL_HEADER void ExportNgOCCShapes(py::module &m)
          }, py::arg("p"), py::arg("s"),
          "copy shape, and scale copy by factor 's'")
 
-    .def("WriteStep", [](TopoDS_Shape shape, string filename)
+    .def("WriteStep", [](const TopoDS_Shape & shape, string & filename)
-         {
+            { step_utils::WriteSTEP(shape, filename); }
-           STEPControl_Writer writer; 
+         , py::arg("filename"), "export shape in STEP - format")
-           writer.Transfer(shape, STEPControl_ManifoldSolidBrep); 
-           
-           // Translates TopoDS_Shape into manifold_solid_brep entity 
-           writer.Write(filename.c_str());
-         }, py::arg("filename"), "export shape in STEP - format")
 
     .def("bc", [](const TopoDS_Shape & shape, const string & name)
          {

libsrc/occ/vsocc.cpp

@@ -549,29 +549,9 @@ namespace netgen
 
          if (!occgeometry->fvispar[i-1].IsHighlighted())
          {
-            // Philippose - 30/01/2009
+            auto c = OCCGeometry::global_shape_properties[face.TShape()].col.value_or(Vec<4>(0,1,0,1) );
-            // OpenCascade XDE Support
+            for(auto j : Range(4))
-            Quantity_Color face_colour;
+               mat_col[j] = c[j];
-            // Philippose - 23/02/2009
-            // Check to see if colours have been extracted first!!
-            // Forum bug-fox (Jean-Yves - 23/02/2009)
-            if(!(occgeometry->face_colours.IsNull())
-               && (occgeometry->face_colours->GetColor(face,XCAFDoc_ColorSurf,face_colour)))
-            {
-               mat_col[0] = face_colour.Red();
-               mat_col[1] = face_colour.Green();
-               mat_col[2] = face_colour.Blue();
-            }
-            else
-            {
-               mat_col[0] = 0.0;
-               mat_col[1] = 1.0;
-               mat_col[2] = 0.0;
-            }
-
-            if(auto c = OCCGeometry::global_shape_properties[face.TShape()].col)
-              for(auto j : Range(4))
-                mat_col[j] = (*c)[j];
          }
          else
          {