0031382: Data Exchange - BinXCAF should preserve length unit information

Possibility for adding LengthUnit info to XCAF document using special class XCAFDoc_LenghtUnit and XCAFDoc_LenghtUnitTool is implemented.
Package UnitsMethods is split: geom methods were placed to new file GeomConvert_Units which is in the toolkit TKXSBase, internal step scale factors was placed to StepData.
Updated UnitMethods to convert scale factor to different unit types.
Now, XSAlgo::XSAlgo_AlgoContainer is used to update unit info from static interface values.
New Draw command "XSetLengthUnit" and "XGetLengthUnit" for set or get XDE attribute.
Upgraded tests for STEP, IGES, OBJ, glTF, VRML formats to check area regressing with used unit.
Upgraded tests\de test cases to use any units in the "loop back" algorithms.

src/STEPCAFControl/STEPCAFControl_Reader.cxx

@@ -47,6 +47,7 @@
 #include <StepBasic_SiUnitAndLengthUnit.hxx>
 #include <StepBasic_Unit.hxx>
 #include <StepBasic_DocumentFile.hxx>
+#include <StepData_GlobalFactors.hxx>
 #include <STEPCAFControl_Controller.hxx>
 #include <STEPCAFControl_DataMapIteratorOfDataMapOfShapePD.hxx>
 #include <STEPCAFControl_DataMapOfPDExternFile.hxx>
@@ -535,6 +536,23 @@ static void FillShapesMap(const TopoDS_Shape &S, TopTools_MapOfShape &map)
     FillShapesMap(it.Value(), map);
 }
 
+//=======================================================================
+//function : prepareUnits
+//purpose  :
+//=======================================================================
+void STEPCAFControl_Reader::prepareUnits(const Handle(StepData_StepModel)& theModel,
+                                         const Handle(TDocStd_Document)& theDoc) const
+{
+  Standard_Real aScaleFactorMM = 1.;
+  if (!XCAFDoc_DocumentTool::GetLengthUnit(theDoc, aScaleFactorMM, UnitsMethods_LengthUnit_Millimeter))
+  {
+    XSAlgo::AlgoContainer()->PrepareForTransfer(); // update unit info
+    aScaleFactorMM = UnitsMethods::GetCasCadeLengthUnit();
+    // Sets length unit to the document
+    XCAFDoc_DocumentTool::SetLengthUnit(theDoc, aScaleFactorMM, UnitsMethods_LengthUnit_Millimeter);
+  }
+  theModel->SetLocalLengthUnit(aScaleFactorMM);
+}
 
 //=======================================================================
 //function : Transfer
@@ -549,6 +567,8 @@ Standard_Boolean STEPCAFControl_Reader::Transfer (STEPControl_Reader &reader,
                                                   const Message_ProgressRange& theProgress)
 {
   reader.ClearShapes();
+  Handle(StepData_StepModel) aModel = Handle(StepData_StepModel)::DownCast(reader.Model());
+  prepareUnits(aModel, doc);
   Standard_Integer i;
 
   // Read all shapes
@@ -582,14 +602,13 @@ Standard_Boolean STEPCAFControl_Reader::Transfer (STEPControl_Reader &reader,
   // from the ones representing hybrid models and shape sets
   STEPCAFControl_DataMapOfShapePD ShapePDMap;
   STEPCAFControl_DataMapOfPDExternFile PDFileMap;
-  Handle(Interface_InterfaceModel) Model = reader.Model();
   const Handle(Transfer_TransientProcess) &TP = reader.WS()->TransferReader()->TransientProcess();
-  Standard_Integer nb = Model->NbEntities();
+  Standard_Integer nb = aModel->NbEntities();
 
   Handle(TColStd_HSequenceOfTransient) SeqPDS = new TColStd_HSequenceOfTransient;
 
   for (i = 1; i <= nb; i++) {
-    Handle(Standard_Transient) enti = Model->Value(i);
+    Handle(Standard_Transient) enti = aModel->Value(i);
     if (enti->IsKind(STANDARD_TYPE(StepRepr_ProductDefinitionShape))) {
       // sequence for acceleration ReadMaterials
       SeqPDS->Append(enti);
@@ -752,7 +771,6 @@ Standard_Boolean STEPCAFControl_Reader::Transfer (STEPControl_Reader &reader,
 
   // Update assembly compounds
   STool->UpdateAssemblies();
-
   return Standard_True;
 }
 
@@ -1983,7 +2001,7 @@ void readAnnotation(const Handle(XSControl_TransferReader)& theTR,
   XSAlgo::AlgoContainer()->PrepareForTransfer();
   STEPControl_ActorRead anActor;
   anActor.PrepareUnits(aDModel, aTP);
-  Standard_Real aFact = UnitsMethods::LengthFactor();
+  Standard_Real aFact = StepData_GlobalFactors::Intance().LengthFactor();
 
   // retrieve AnnotationPlane
   Handle(StepRepr_RepresentationItem) aDMIAE = aDMIA->IdentifiedItemValue(1);
@@ -2090,7 +2108,7 @@ void readConnectionPoints(const Handle(XSControl_TransferReader)& theTR,
     XSAlgo::AlgoContainer()->PrepareForTransfer();
     STEPControl_ActorRead anActor;
     anActor.PrepareUnits(aSDR, aTP);
-    aFact = UnitsMethods::LengthFactor();
+    aFact = StepData_GlobalFactors::Intance().LengthFactor();
   }
   
   if (theGDT->IsKind(STANDARD_TYPE(StepShape_DimensionalSize))) {
@@ -4032,7 +4050,7 @@ Standard_Boolean STEPCAFControl_Reader::ReadGDTs(const Handle(XSControl_WorkSess
         STEPControl_ActorRead anActor;
         Handle(Transfer_TransientProcess) aTP = aTR->TransientProcess();
         anActor.PrepareUnits(aDMIA->UsedRepresentation(), aTP);
-        aFact = UnitsMethods::LengthFactor();
+        aFact = StepData_GlobalFactors::Intance().LengthFactor();
       }
 
       // Presentation
@@ -4196,8 +4214,8 @@ Standard_Boolean STEPCAFControl_Reader::ReadMaterials(const Handle(XSControl_Wor
                   aDensity = aDensity / (anUnitCtx.LengthFactor()*anUnitCtx.LengthFactor()*anUnitCtx.LengthFactor());
                   // transfer length value for Density from millimeter to santimeter
                   // in order to result density has dimension gram/(sm*sm*sm)
-                  aDensity = aDensity*1000. / (UnitsMethods::GetCasCadeLengthUnit()
-                    * UnitsMethods::GetCasCadeLengthUnit() * UnitsMethods::GetCasCadeLengthUnit());
+                  const Standard_Real aCascadeUnit = StepData_GlobalFactors::Intance().CascadeUnit();
+                  aDensity = aDensity*1000. / (aCascadeUnit * aCascadeUnit * aCascadeUnit);
                 }
                 if (NU->IsKind(STANDARD_TYPE(StepBasic_ConversionBasedUnitAndMassUnit))) {
                   Standard_Real afact = 1.;

src/STEPCAFControl/STEPCAFControl_Reader.hxx

@@ -291,6 +291,11 @@ private:
     const Handle(TDocStd_Document)& theDoc,
     const Handle(XSControl_WorkSession)& theWS);
 
+  //! Prepares units for transfer
+  void prepareUnits(const Handle(StepData_StepModel)& theModel,
+                    const Handle(TDocStd_Document)& theDoc) const;
+
+private:
 
   STEPControl_Reader myReader;
   NCollection_DataMap<TCollection_AsciiString, Handle(STEPCAFControl_ExternFile)> myFiles;

src/STEPCAFControl/STEPCAFControl_Writer.cxx

@@ -228,6 +228,7 @@
 #include <XCAFDoc_DocumentTool.hxx>
 #include <XCAFDoc_GeomTolerance.hxx>
 #include <XCAFDoc_GraphNode.hxx>
+#include <XCAFDoc_LengthUnit.hxx>
 #include <XCAFDoc_LayerTool.hxx>
 #include <XCAFDoc_Material.hxx>
 #include <XCAFDoc_MaterialTool.hxx>
@@ -240,8 +241,11 @@
 #include <XCAFPrs_IndexedDataMapOfShapeStyle.hxx>
 #include <XCAFPrs_DataMapOfStyleShape.hxx>
 #include <XCAFPrs_Style.hxx>
+#include <XSAlgo.hxx>
+#include <XSAlgo_AlgoContainer.hxx>
 #include <XSControl_TransferWriter.hxx>
 #include <XSControl_WorkSession.hxx>
+#include <UnitsMethods.hxx>
 
 // added by skl 15.01.2004 for D&GT writing
 //#include <StepRepr_CompoundItemDefinition.hxx>
@@ -359,6 +363,25 @@ IFSelect_ReturnStatus STEPCAFControl_Writer::Write (const Standard_CString filen
   return status;
 }
 
+//=======================================================================
+//function : prepareUnit
+//purpose  :
+//=======================================================================
+void STEPCAFControl_Writer::prepareUnit(const TDF_Label& theLabel,
+                                        const Handle(StepData_StepModel)& theModel)
+{
+  Handle(XCAFDoc_LengthUnit) aLengthAttr;
+  if (!theLabel.IsNull() &&
+    theLabel.Root().FindAttribute(XCAFDoc_LengthUnit::GetID(), aLengthAttr))
+  {
+    theModel->SetLocalLengthUnit(aLengthAttr->GetUnitValue() * 1000); // convert to mm
+  }
+  else
+  {
+    XSAlgo::AlgoContainer()->PrepareForTransfer(); // update unit info
+    theModel->SetLocalLengthUnit(UnitsMethods::GetCasCadeLengthUnit());
+  }
+}
 
 //=======================================================================
 //function : Transfer
@@ -516,6 +539,8 @@ Standard_Boolean STEPCAFControl_Writer::Transfer (STEPControl_Writer &writer,
   Handle(STEPCAFControl_ActorWrite) Actor =
     Handle(STEPCAFControl_ActorWrite)::DownCast ( writer.WS()->NormAdaptor()->ActorWrite() );
 
+  const Handle(StepData_StepModel) aModel = Handle(StepData_StepModel)::DownCast(writer.WS()->Model());
+  prepareUnit(labels.First(), aModel); // set local length unit to the model
   // translate free top-level shapes of the DECAF document
   Standard_Integer ap = Interface_Static::IVal ("write.step.schema");
   TDF_LabelSequence sublabels;
@@ -659,10 +684,9 @@ Standard_Boolean STEPCAFControl_Writer::Transfer (STEPControl_Writer &writer,
       WriteMaterials(writer.WS(),sublabels);
 
     // register all MDGPRs in model
-    const Handle(Interface_InterfaceModel) &Model = writer.WS()->Model();
     MoniTool_DataMapIteratorOfDataMapOfShapeTransient anItr(myMapCompMDGPR);
     for (; anItr.More(); anItr.Next())
-      Model->AddWithRefs( anItr.Value() );
+      aModel->AddWithRefs( anItr.Value() );
   }
   
   if ( multi ) { // external refs

src/STEPCAFControl/STEPCAFControl_Writer.hxx

@@ -92,6 +92,12 @@ public:
                                              const Standard_CString multi = 0,
                                              const Message_ProgressRange& theProgress = Message_ProgressRange());
 
+  //! Mehod to writing sequence of root assemblies or part of the file specified by use by one label 
+  Standard_EXPORT Standard_Boolean Transfer (const TDF_LabelSequence& L,
+                                             const STEPControl_StepModelType mode = STEPControl_AsIs,
+                                             const Standard_CString multi = 0,
+                                             const Message_ProgressRange& theProgress = Message_ProgressRange());
+
   Standard_EXPORT Standard_Boolean Perform (const Handle(TDocStd_Document)& doc,
                                             const TCollection_AsciiString& filename,
                                             const Message_ProgressRange& theProgress = Message_ProgressRange());
@@ -155,15 +161,7 @@ public:
   
   Standard_EXPORT Standard_Boolean GetMaterialMode() const;
 
-
-
-
 protected:
-  //! Mehod to writing sequence of root assemblies or part of the file specified by use by one label 
-  Standard_EXPORT Standard_Boolean Transfer (const TDF_LabelSequence& L,
-                                             const STEPControl_StepModelType mode = STEPControl_AsIs,
-                                             const Standard_CString multi = 0,
-                                             const Message_ProgressRange& theProgress = Message_ProgressRange());
   
   //! Transfers labels to a STEP model
   //! Returns True if translation is OK
@@ -215,9 +213,14 @@ protected:
   //! Write SHUO assigned to specified component, to STEP model
   Standard_EXPORT Standard_Boolean WriteSHUOs (const Handle(XSControl_WorkSession)& WS, const TDF_LabelSequence& labels);
 
-  
+  //! Finds length units located in root of label
+  //! If it exists, initializes local length unit from it
+  //! Else initializes according to Cascade length unit
+  Standard_EXPORT void prepareUnit(const TDF_Label& theLabel,
+                                   const Handle(StepData_StepModel)& theModel);
 
 private:
+
   Standard_EXPORT Handle(StepRepr_ShapeAspect) WriteShapeAspect(const Handle(XSControl_WorkSession) &WS,
     const TDF_Label theLabel, const TopoDS_Shape theShape, Handle(StepRepr_RepresentationContext)& theRC,
     Handle(StepAP242_GeometricItemSpecificUsage)& theGISU);
@@ -236,6 +239,7 @@ private:
     const TDF_Label theGeomTolL, const Handle(StepDimTol_HArray1OfDatumSystemOrReference)& theDatumSystem,
     const Handle(StepRepr_RepresentationContext)& theRC);
 
+private:
 
 
   STEPControl_Writer myWriter;