0027271: Unifysamedomain invalid result

Prevent merging of faces along periodic direction.

Test case "bugs heal bug27000_1" has been corrected to actual state of the algorithm.

src/ShapeUpgrade/ShapeUpgrade_UnifySameDomain.cxx

@@ -86,6 +86,8 @@
 #include <gp_Circ.hxx>
 #include <BRepAdaptor_Curve.hxx>
 #include <BRepClass_FaceClassifier.hxx>
+#include <BRepAdaptor_Curve2d.hxx>
+#include <gp_Vec2d.hxx>
 
 IMPLEMENT_STANDARD_RTTIEXT(ShapeUpgrade_UnifySameDomain,MMgt_TShared)
 
@@ -95,6 +97,42 @@ struct SubSequenceOfEdges
   TopoDS_Edge UnionEdges;
 };
 
+static Standard_Boolean IsLikeSeam(const TopoDS_Edge& anEdge,
+                                   const TopoDS_Face& aFace,
+                                   const Handle(Geom_Surface)& aBaseSurface)
+{
+  if (!aBaseSurface->IsUPeriodic() && !aBaseSurface->IsVPeriodic())
+    return Standard_False;
+
+  BRepAdaptor_Curve2d BAcurve2d(anEdge, aFace);
+  gp_Pnt2d FirstPoint, LastPoint;
+  gp_Vec2d FirstDir, LastDir;
+  BAcurve2d.D1(BAcurve2d.FirstParameter(), FirstPoint, FirstDir);
+  BAcurve2d.D1(BAcurve2d.LastParameter(),  LastPoint,  LastDir);
+  Standard_Real Length = FirstDir.Magnitude();
+  if (Length <= gp::Resolution())
+    return Standard_False;
+  else
+    FirstDir /= Length;
+  Length = LastDir.Magnitude();
+  if (Length <= gp::Resolution())
+    return Standard_False;
+  else
+    LastDir /= Length;
+  
+  Standard_Real Tol = 1.e-7;
+  if (aBaseSurface->IsUPeriodic() &&
+    (Abs(FirstDir.X()) < Tol) &&
+    (Abs(LastDir.X()) < Tol))
+    return Standard_True;
+
+  if (aBaseSurface->IsVPeriodic() &&
+    (Abs(FirstDir.Y()) < Tol) &&
+    (Abs(LastDir.Y()) < Tol))
+    return Standard_True;
+
+  return Standard_False;
+}
 
 //=======================================================================
 //function : AddOrdinaryEdges
@@ -1200,6 +1238,10 @@ void ShapeUpgrade_UnifySameDomain::UnifyFaces()
 
           if (IsSameDomain(aFace,anCheckedFace)) {
 
+            // hotfix for 27271: prevent merging along periodic direction.
+            if (IsLikeSeam(edge, aFace, aBaseSurface))
+              continue;
+
             // replacing pcurves
             TopoDS_Face aMockUpFace;
             BRep_Builder B;

tests/bugs/heal/bug27000_1

@@ -1,4 +1,4 @@
 restore [locate_data_file bug27000_1.brep] shape
 unifysamedom result shape
 checkshape result
-checknbshapes result -vertex 60 -edge 87 -wire 35 -face 33 -shell 2 -solid 2 -compsolid 0 -compound 1 -shape 220
+checknbshapes result -vertex 62 -edge 90 -wire 36 -face 34 -shell 2 -solid 2 -compsolid 0 -compound 1 -shape 227

tests/bugs/modalg_6/bug27271

@@ -0,0 +1,11 @@
+puts "============"
+puts "OCC27271"
+puts "============"
+puts ""
+###########################################################################################################
+# Unifysamedomain invalid result
+###########################################################################################################
+
+restore [locate_data_file bug27271_Shape.brep] a
+unifysamedom result a
+checkshape result