diff --git a/src/Contap/Contap_Contour.cxx b/src/Contap/Contap_Contour.cxx
index 1b071f9351..0bcc1c6302 100644
--- a/src/Contap/Contap_Contour.cxx
+++ b/src/Contap/Contap_Contour.cxx
@@ -308,9 +308,14 @@ static void LineConstructor(Contap_TheSequenceOfLine& slin,
                                       //-- cout<<"ContapWLine      : firtsp="<<firstp<<" lastp="<<lastp<<" Vtx:"<<i<<","<<i+1<<endl;
                                       Handle(IntSurf_LineOn2S) LineOn2S = new IntSurf_LineOn2S();
                                       Contap_Line Line;
+                                      Standard_Real aLen = 0.;
                                       for(Standard_Integer j=firstp; j<=lastp; j++) { 
                                         LineOn2S->Add(L.Point(j));
+                                        if (j > firstp)
+                                          aLen += L.Point(j).Value().Distance(L.Point(j - 1).Value());
                                       }
+                                      if (aLen < Precision::Confusion())
+                                        continue;
                                       Line.SetLineOn2S(LineOn2S);
                                       Contap_Point pvtx = L.Vertex(i);
                                       pvtx.SetParameter(1);
diff --git a/tests/bugs/modalg_6/bug27720_5 b/tests/bugs/modalg_6/bug27720_5
index 167ba2a564..b90f52e510 100644
--- a/tests/bugs/modalg_6/bug27720_5
+++ b/tests/bugs/modalg_6/bug27720_5
@@ -21,6 +21,6 @@ build3d result
 fit
 
 checkprops result -l 0.841499
-checknbshapes result -vertex 92 -edge 46
+checknbshapes result -vertex 94 -edge 47
 
 checkview -screenshot -2d -path ${imagedir}/${test_image}.png