[bos #38643][EDF] Laplacian Smoothing 2D.

Add support to periodic faces to the laplacian smoother.

.

Add support to periodic faces to the centroidalSmooth.

Do not move singular nodes that are placed in the surface instead of on the edge as in the BodyFitting algorithm.

Small modif in averageByElement to not initialize theUVMap unproperly when theSurface.IsNull().

doc/examples/modifying_meshes_ex21.py

@@ -11,7 +11,8 @@ group_smooth = mesh.GroupOnGeom(faces[3], "Group of faces (smooth)", SMESH.FACE)
 # perform smoothing
 
 # boolean SmoothObject(Object, IDsOfFixedNodes, MaxNbOfIterations, MaxAspectRatio, Method)
-res = mesh.SmoothObject(group_smooth, [], 20, 2., smesh_builder.CENTROIDAL_SMOOTH)
+res0 = mesh.SmoothObject(group_smooth, [], 20, 2., smesh_builder.CENTROIDAL_SMOOTH)
+res1 = mesh.SmoothObject(group_smooth, [], 20, 2., smesh_builder.LAPLACIAN_SMOOTH)
 print("\nSmoothing ... ", end=' ')
-if not res: print("failed!")
+if not (res0 and res1): print("failed!")
 else:       print("done.")

src/SMESH/SMESH_MeshEditor.cxx

@@ -62,6 +62,8 @@
 #include <Geom_Curve.hxx>
 #include <Geom_Surface.hxx>
 #include <Precision.hxx>
+#include <ShapeAnalysis.hxx>
+#include <ShapeAnalysis_Curve.hxx>
 #include <TColStd_ListOfInteger.hxx>
 #include <TopAbs_State.hxx>
 #include <TopExp.hxx>
@@ -3849,6 +3851,68 @@ void SMESH_MeshEditor::GetLinkedNodes( const SMDS_MeshNode* theNode,
   }
 }
 
+//=======================================================================
+//function : averageBySurface
+//purpose  : Auxiliar function to treat properly nodes in periodic faces in the laplacian smoother
+//=======================================================================
+void averageBySurface( const Handle(Geom_Surface)& theSurface, const SMDS_MeshNode* refNode, 
+                        TIDSortedElemSet& nodeSet, map< const SMDS_MeshNode*, gp_XY* >& theUVMap, double * coord )
+{
+  if ( theSurface.IsNull() ) 
+  {
+    TIDSortedElemSet::iterator nodeSetIt = nodeSet.begin();
+    for ( ; nodeSetIt != nodeSet.end(); nodeSetIt++ ) 
+    {
+      const SMDS_MeshNode* node = cast2Node(*nodeSetIt);
+      coord[0] += node->X();
+      coord[1] += node->Y();
+      coord[2] += node->Z();
+    }
+  }
+  else
+  {
+    Standard_Real Umin,Umax,Vmin,Vmax;
+    theSurface->Bounds( Umin, Umax, Vmin, Vmax );
+    ASSERT( theUVMap.find( refNode ) != theUVMap.end() );
+    gp_XY* nodeUV = theUVMap[ refNode ];
+    Standard_Real uref = nodeUV->X();
+    Standard_Real vref = nodeUV->Y();
+
+    TIDSortedElemSet::iterator nodeSetIt = nodeSet.begin();
+    for ( ; nodeSetIt != nodeSet.end(); nodeSetIt++ ) 
+    {
+      const SMDS_MeshNode* node = cast2Node(*nodeSetIt);
+      ASSERT( theUVMap.find( node ) != theUVMap.end() );
+      gp_XY* uv = theUVMap[ node ];    
+
+      if ( theSurface->IsUPeriodic() || theSurface->IsVPeriodic() )  
+      {          
+        Standard_Real u          = uv->X();
+        Standard_Real v          = uv->Y();                      
+        Standard_Real uCorrected = u;
+        Standard_Real vCorrected = v;
+        bool isUTobeCorrected = (std::fabs( uref - u ) >= 0.7 * std::fabs( Umax - Umin ));
+        bool isVTobeCorrected = (std::fabs( vref - v ) >= 0.7 * std::fabs( Vmax - Vmin ));
+
+        if( isUTobeCorrected  )
+          uCorrected = uref > u ? Umax + std::fabs(Umin - u) : Umin - std::fabs(Umax - u);
+
+        if( isVTobeCorrected )
+          vCorrected = vref > v ? Vmax + std::fabs(Vmin - v) : Vmin - std::fabs(Vmax - v);
+        
+        coord[0] += uCorrected;
+        coord[1] += vCorrected;
+
+      }
+      else
+      {
+        coord[0] += uv->X();
+        coord[1] += uv->Y();
+      }
+    }   
+  }
+}
+
 //=======================================================================
 //function : laplacianSmooth
 //purpose  : pulls theNode toward the center of surrounding nodes directly
@@ -3865,26 +3929,14 @@ void laplacianSmooth(const SMDS_MeshNode*                 theNode,
   SMESH_MeshEditor::GetLinkedNodes( theNode, nodeSet, SMDSAbs_Face );
 
   // compute new coodrs
+  double coord[] = { 0., 0., 0. };  
+
+  averageBySurface( theSurface, theNode, nodeSet, theUVMap, coord );
 
-  double coord[] = { 0., 0., 0. };
-  TIDSortedElemSet::iterator nodeSetIt = nodeSet.begin();
-  for ( ; nodeSetIt != nodeSet.end(); nodeSetIt++ ) {
-    const SMDS_MeshNode* node = cast2Node(*nodeSetIt);
-    if ( theSurface.IsNull() ) { // smooth in 3D
-      coord[0] += node->X();
-      coord[1] += node->Y();
-      coord[2] += node->Z();
-    }
-    else { // smooth in 2D
-      ASSERT( theUVMap.find( node ) != theUVMap.end() );
-      gp_XY* uv = theUVMap[ node ];
-      coord[0] += uv->X();
-      coord[1] += uv->Y();
-    }
-  }
   int nbNodes = nodeSet.size();
   if ( !nbNodes )
     return;
+
   coord[0] /= nbNodes;
   coord[1] /= nbNodes;
 
@@ -3894,7 +3946,7 @@ void laplacianSmooth(const SMDS_MeshNode*                 theNode,
     gp_Pnt p3d = theSurface->Value( coord[0], coord[1] );
     coord[0] = p3d.X();
     coord[1] = p3d.Y();
-    coord[2] = p3d.Z();
+    coord[2] = p3d.Z();    
   }
   else
     coord[2] /= nbNodes;
@@ -3904,6 +3956,72 @@ void laplacianSmooth(const SMDS_MeshNode*                 theNode,
   const_cast< SMDS_MeshNode* >( theNode )->setXYZ(coord[0],coord[1],coord[2]);
 }
 
+//=======================================================================
+//function : correctTheValue
+//purpose  : Given a boundaries of parametric space determine if the node coordinate (u,v) need correction 
+//            based on the reference coordinate (uref,vref)
+//=======================================================================
+void correctTheValue( Standard_Real Umax, Standard_Real Umin, Standard_Real Vmax, Standard_Real Vmin, 
+                        Standard_Real uref, Standard_Real vref, Standard_Real &u, Standard_Real &v  )
+{
+  bool isUTobeCorrected = (std::fabs( uref - u ) >= 0.7 * std::fabs( Umax - Umin ));
+  bool isVTobeCorrected = (std::fabs( vref - v ) >= 0.7 * std::fabs( Vmax - Vmin ));
+  if ( isUTobeCorrected )
+    u = std::fabs(u-Umin) < 1e-7 ? Umax : Umin;            
+  if ( isVTobeCorrected )
+    v = std::fabs(v-Vmin) < 1e-7 ? Vmax : Vmin;
+}
+
+//=======================================================================
+//function : averageByElement
+//purpose  : Auxiliar function to treat properly nodes in periodic faces in the centroidal smoother
+//=======================================================================
+void averageByElement( const Handle(Geom_Surface)& theSurface, const SMDS_MeshNode* refNode, const SMDS_MeshElement* elem,
+                        map< const SMDS_MeshNode*, gp_XY* >& theUVMap, SMESH::Controls::TSequenceOfXYZ& aNodePoints, 
+                        gp_XYZ& elemCenter )
+{
+  int nn = elem->NbNodes();
+  if(elem->IsQuadratic()) nn = nn/2;
+  int i=0;
+  SMDS_ElemIteratorPtr itN = elem->nodesIterator();
+  Standard_Real Umin,Umax,Vmin,Vmax;
+  while ( i<nn ) 
+  {
+    const SMDS_MeshNode* aNode = static_cast<const SMDS_MeshNode*>( itN->next() );
+    i++;
+    gp_XYZ aP( aNode->X(), aNode->Y(), aNode->Z() );
+    aNodePoints.push_back( aP );
+    if ( !theSurface.IsNull() ) // smooth in 2D
+    { 
+      ASSERT( theUVMap.find( aNode ) != theUVMap.end() );
+      gp_XY* uv = theUVMap[ aNode ];
+
+      if ( theSurface->IsUPeriodic() || theSurface->IsVPeriodic() )  
+      {  
+        theSurface->Bounds( Umin, Umax, Vmin, Vmax );
+        Standard_Real u          = uv->X();
+        Standard_Real v          = uv->Y();   
+        bool isSingularPoint     = std::fabs(u - Umin) < 1e-7 || std::fabs(v - Vmin) < 1e-7 || std::fabs(u - Umax) < 1e-7 || std::fabs( v - Vmax ) < 1e-7;
+        if ( !isSingularPoint )
+        {
+          aP.SetCoord( uv->X(), uv->Y(), 0. );
+        }
+        else
+        {
+          gp_XY* refPoint = theUVMap[ refNode ];
+          Standard_Real uref = refPoint->X();
+          Standard_Real vref = refPoint->Y();
+          correctTheValue( Umax, Umin, Vmax, Vmin, uref, vref, u, v ); 
+          aP.SetCoord( u, v, 0. );
+        }        
+      }
+      else
+        aP.SetCoord( uv->X(), uv->Y(), 0. );
+    }    
+    elemCenter += aP;   
+  }
+}
+
 //=======================================================================
 //function : centroidalSmooth
 //purpose  : pulls theNode toward the element-area-weighted centroid of the
@@ -3918,48 +4036,46 @@ void centroidalSmooth(const SMDS_MeshNode*                 theNode,
   SMESH::Controls::Area anAreaFunc;
   double totalArea = 0.;
   int nbElems = 0;
-
   // compute new XYZ
-
+  bool notToMoveNode = false;
+  // Do not correct singular nodes
+  if ( !theSurface.IsNull() && (theSurface->IsUPeriodic() || theSurface->IsVPeriodic()) )
+  { 
+    Standard_Real Umin,Umax,Vmin,Vmax;
+    theSurface->Bounds( Umin, Umax, Vmin, Vmax );
+    gp_XY* uv = theUVMap[ theNode ];
+    Standard_Real u = uv->X();
+    Standard_Real v = uv->Y();   
+    notToMoveNode = std::fabs(u - Umin) < 1e-7 || std::fabs(v - Vmin) < 1e-7 || std::fabs(u - Umax) < 1e-7 || std::fabs( v - Vmax ) < 1e-7;
+  }
+  
   SMDS_ElemIteratorPtr elemIt = theNode->GetInverseElementIterator(SMDSAbs_Face);
-  while ( elemIt->more() )
+  while ( elemIt->more() && !notToMoveNode )
   {
     const SMDS_MeshElement* elem = elemIt->next();
     nbElems++;
 
     gp_XYZ elemCenter(0.,0.,0.);
     SMESH::Controls::TSequenceOfXYZ aNodePoints;
-    SMDS_ElemIteratorPtr itN = elem->nodesIterator();
     int nn = elem->NbNodes();
     if(elem->IsQuadratic()) nn = nn/2;
-    int i=0;
+    averageByElement( theSurface, theNode, elem, theUVMap, aNodePoints, elemCenter );
-    //while ( itN->more() ) {
+
-    while ( i<nn ) {
-      const SMDS_MeshNode* aNode = static_cast<const SMDS_MeshNode*>( itN->next() );
-      i++;
-      gp_XYZ aP( aNode->X(), aNode->Y(), aNode->Z() );
-      aNodePoints.push_back( aP );
-      if ( !theSurface.IsNull() ) { // smooth in 2D
-        ASSERT( theUVMap.find( aNode ) != theUVMap.end() );
-        gp_XY* uv = theUVMap[ aNode ];
-        aP.SetCoord( uv->X(), uv->Y(), 0. );
-      }
-      elemCenter += aP;
-    }
     double elemArea = anAreaFunc.GetValue( aNodePoints );
     totalArea += elemArea;
     elemCenter /= nn;
     aNewXYZ += elemCenter * elemArea;
   }
   aNewXYZ /= totalArea;
-  if ( !theSurface.IsNull() ) {
+  
+  if ( !theSurface.IsNull() && !notToMoveNode ) {
     theUVMap[ theNode ]->SetCoord( aNewXYZ.X(), aNewXYZ.Y() );
     aNewXYZ = theSurface->Value( aNewXYZ.X(), aNewXYZ.Y() ).XYZ();
   }
 
   // move node
-
+  if ( !notToMoveNode )
-  const_cast< SMDS_MeshNode* >( theNode )->setXYZ(aNewXYZ.X(),aNewXYZ.Y(),aNewXYZ.Z());
+    const_cast< SMDS_MeshNode* >( theNode )->setXYZ(aNewXYZ.X(),aNewXYZ.Y(),aNewXYZ.Z());
 }
 
 //=======================================================================
@@ -4262,7 +4378,8 @@ void SMESH_MeshEditor::Smooth (TIDSortedElemSet &          theElems,
         if ( !BRep_Tool::IsClosed( edge, face ))
           continue;
         SMESHDS_SubMesh* sm = aMesh->MeshElements( edge );
-        if ( !sm ) continue;
+        if ( !sm )
+          continue;
         // find out which parameter varies for a node on seam
         double f,l;
         gp_Pnt2d uv1, uv2;