diff --git a/src/ShapeUpgrade/ShapeUpgrade_UnifySameDomain.cxx b/src/ShapeUpgrade/ShapeUpgrade_UnifySameDomain.cxx
index 2dc4fefca0..5b1d742945 100644
--- a/src/ShapeUpgrade/ShapeUpgrade_UnifySameDomain.cxx
+++ b/src/ShapeUpgrade/ShapeUpgrade_UnifySameDomain.cxx
@@ -614,24 +614,48 @@ static Standard_Boolean MergeSubSeq(const TopTools_SequenceOfShape& aChain, Topo
     Handle(Geom_Circle) Cir = Handle(Geom_Circle)::DownCast(c3d);
 
     TopoDS_Vertex V1 = sae.FirstVertex(FE);
-    gp_Pnt PV1 = BRep_Tool::Pnt(V1);
     TopoDS_Vertex V2 = sae.LastVertex(TopoDS::Edge(aChain.Last()));
-    gp_Pnt PV2 = BRep_Tool::Pnt(V2);
-    TopoDS_Vertex VM = sae.LastVertex(FE);
-    gp_Pnt PVM = BRep_Tool::Pnt(VM);
-    GC_MakeCircle MC (PV1,PVM,PV2);
     TopoDS_Edge E;
-    if (!MC.IsDone() || MC.Value().IsNull()) {
-      // jfa for Mantis issue 0020228
-      if (PV1.Distance(PV2) > Precision::Confusion())
-        return Standard_False;
+    if (V1.IsSame(V2)) {
       // closed chain
-      B.MakeEdge (E,Cir,Precision::Confusion());
-      B.Add(E,V1);
-      B.Add(E,V2);
-      E.Orientation(FE.Orientation());
+      BRepAdaptor_Curve adef(FE);
+      Handle(Geom_Circle) Cir1;
+      double FP, LP;
+      if ( FE.Orientation() == TopAbs_FORWARD)
+      {
+        FP = adef.FirstParameter();
+        LP = adef.LastParameter();
+      }
+      else
+      {
+        FP = adef.LastParameter();
+        LP = adef.FirstParameter();
+      }
+      if (Abs(FP) < Precision::PConfusion())
+      {
+        B.MakeEdge (E,Cir, Precision::Confusion());
+        B.Add(E,V1);
+        B.Add(E,V2);
+        E.Orientation(FE.Orientation());
+      }
+      else
+      {
+        GC_MakeCircle MC1 (adef.Value(FP), adef.Value((FP + LP) * 0.5), adef.Value(LP));
+        if (MC1.IsDone())
+          Cir1 = MC1.Value();
+        else
+          return Standard_False;
+        B.MakeEdge (E, Cir1, Precision::Confusion());
+        B.Add(E,V1);
+        B.Add(E,V2);
+      }
     }
     else {
+      gp_Pnt PV1 = BRep_Tool::Pnt(V1);
+      gp_Pnt PV2 = BRep_Tool::Pnt(V2);
+      TopoDS_Vertex VM = sae.LastVertex(FE);
+      gp_Pnt PVM = BRep_Tool::Pnt(VM);
+      GC_MakeCircle MC (PV1,PVM,PV2);
       Handle(Geom_Circle) C = MC.Value();
       gp_Pnt P0 = C->Location();
       gp_Dir D1(gp_Vec(P0,PV1));
diff --git a/tests/bugs/heal/bug26244 b/tests/bugs/heal/bug26244
new file mode 100644
index 0000000000..2d8385e783
--- /dev/null
+++ b/tests/bugs/heal/bug26244
@@ -0,0 +1,286 @@
+puts "=========="
+puts "OCC26244"
+puts "=========="
+puts ""
+###########################################
+# Destructive results of simplification with DRAW command 'unifysamedom' after intersection of two complex models
+###########################################
+
+set my_pi 3.1415926535897931
+set aModelHeight 178.25
+set aPlatformLength 426.25
+set aPlatformWidth 201.5
+set aPlatformHeight 58.9
+set aPrismLength 279
+set aPrismWidth 155
+set aPrismHeight [expr $aModelHeight - $aPlatformHeight]
+set aPrismXOffset [expr $aPlatformLength - $aPrismLength - 69.75]
+set aPrismYOffset [expr ($aPlatformWidth - $aPrismWidth)/2]
+
+#================================================================================
+# A base of the model
+box _platform $aPlatformLength $aPlatformWidth $aPlatformHeight
+
+# Make screw holes on the platform
+set aScrewHoleRadius [expr 26.2/2]
+set aScrewHoleOffset 31
+pcylinder _screwhole $aScrewHoleRadius $aPlatformHeight
+ttranslate _screwhole $aScrewHoleOffset $aScrewHoleOffset 0
+bcut _platform _platform _screwhole
+reset _screwhole
+ttranslate _screwhole [expr $aPlatformLength - $aScrewHoleOffset] $aScrewHoleOffset 0
+bcut _platform _platform _screwhole
+reset _screwhole
+ttranslate _screwhole [expr $aPlatformLength - $aScrewHoleOffset] [expr $aPlatformWidth - $aScrewHoleOffset] 0
+bcut _platform _platform _screwhole
+reset _screwhole
+ttranslate _screwhole $aScrewHoleOffset [expr $aPlatformWidth - $aScrewHoleOffset] 0
+bcut _platform _platform _screwhole
+reset _screwhole
+
+# Back side cave
+set aCaveLength 81.38
+set aCaveDepth 10
+set aCaveWidth 19.38
+set aBottomLevel [expr $aPlatformHeight/2 - $aCaveWidth/2]
+set aTopLevel [expr $aPlatformHeight/2 + $aCaveWidth/2]
+beziercurve t_bcurve 4  0 $aCaveLength $aBottomLevel  3  0 [expr $aCaveLength + $aCaveWidth/2] $aBottomLevel 6  0 [expr $aCaveLength + $aCaveWidth/2] $aTopLevel 6  0 $aCaveLength $aTopLevel 3
+vertex t_v1 0 $aCaveLength $aBottomLevel
+vertex t_v2 0 $aCaveLength $aTopLevel
+mkedge t_e1 t_bcurve
+edge t_e2 t_v1 t_v2
+wire t_w t_e1 t_e2
+mkplane t_f1 t_w
+prism t_s1 t_f1 $aCaveDepth 0 0
+box t_s2 0 0 $aBottomLevel $aCaveDepth $aCaveLength $aCaveWidth
+bfuse _backcave t_s1 t_s2
+bcut _platform _platform _backcave
+
+# Right side cave
+set aRCaveRadius 26.2
+set aRCaveDistToSection 15.5
+set aCurveParam [expr ($my_pi - acos($aRCaveDistToSection/$aRCaveRadius))]
+set aRCaveCenterX [expr $aPlatformLength - 162.75]
+set aRCaveCenterZ [expr $aPlatformHeight/2]
+circle t_circle $aRCaveCenterX 0 $aRCaveCenterZ 0 1 0 1 0 0 $aRCaveRadius
+trim t_curve t_circle -$aCurveParam $aCurveParam
+mkedge t_e1 t_curve
+cvalue t_curve -$aCurveParam t_x t_y t_z
+vertex t_v1 t_x t_y t_z
+cvalue t_curve $aCurveParam t_x t_y t_z
+vertex t_v2 t_x t_y t_z
+edge t_e2 t_v1 t_v2
+wire t_w t_e1 t_e2
+mkplane t_f t_w
+prism t_s t_f 0 $aCaveDepth 0
+bcut _platform _platform t_s
+
+# Caves on front side
+set aFCaveCirclesRadius 4.65
+set aFCaveBottomWidth 37.8
+set aFCaveHeight 38.75
+set aFCaveTopWidth 27
+set aFCaveSmallCircleRadius 9.3
+circle t_circle1 [expr $aFCaveTopWidth/2] [expr $aFCaveHeight/2] $aFCaveCirclesRadius
+circle t_circle2 [expr -$aFCaveTopWidth/2] [expr $aFCaveHeight/2] $aFCaveCirclesRadius
+circle t_circle3 [expr -$aFCaveBottomWidth/2] [expr -$aFCaveHeight/2] $aFCaveCirclesRadius
+circle t_circle4 [expr $aFCaveBottomWidth/2] [expr -$aFCaveHeight/2] $aFCaveCirclesRadius
+
+lintan t_l t_circle1 t_circle2
+trim t_side1 t_l_1 0 $aFCaveTopWidth
+
+lintan t_l t_circle2 t_circle3
+trim t_side2 t_l_1 0 39.058577803089555
+
+lintan t_l t_circle3 t_circle4
+trim t_side3 t_l_1 0 $aFCaveBottomWidth
+
+lintan t_l t_circle4 t_circle1
+trim t_side4 t_l_1 0 39.196587861700415
+
+trim t_circle1 t_circle1 0.15109758878146562 1.5707963267948966 
+trim t_circle2 t_circle2 1.5707963267948966 3.0158086349284448
+trim t_circle3 t_circle3 3.0158086349284448 4.7123889803846897 
+trim t_circle4 t_circle4 4.7123889803846897 0.15109758878146562 
+
+plane t_plane 0 0 0 1 0 0 0 1 0
+
+to3d t_circle1 t_circle1 t_plane
+to3d t_circle2 t_circle2 t_plane
+to3d t_circle3 t_circle3 t_plane
+to3d t_circle4 t_circle4 t_plane
+to3d t_side1 t_side1 t_plane
+to3d t_side2 t_side2 t_plane
+to3d t_side3 t_side3 t_plane
+to3d t_side4 t_side4 t_plane
+
+mkedge t_e1 t_circle1
+mkedge t_e2 t_side1
+mkedge t_e3 t_circle2
+mkedge t_e4 t_side2
+mkedge t_e5 t_circle3
+mkedge t_e6 t_side3
+mkedge t_e7 t_circle4
+mkedge t_e8 t_side4
+
+wire t_w t_e1 t_e2 t_e3 t_e4 t_e5 t_e6 t_e7 t_e8
+mkplane t_f t_w
+prism t_s1 t_f -$aCaveDepth 0 0
+
+circle t_circle 0 [expr $aFCaveTopWidth/2 + $aFCaveBottomWidth/2] 0 1 0 0 $aFCaveSmallCircleRadius
+mkedge t_e t_circle
+wire t_w t_e
+mkplane t_f t_w
+prism t_s2 t_f [expr -$aCaveDepth/2] 0 0
+
+box t_s3 0 0 -$aFCaveSmallCircleRadius  [expr -$aCaveDepth/2] [expr $aFCaveTopWidth/2 + $aFCaveBottomWidth/2] [expr $aFCaveSmallCircleRadius*2]
+
+# Compile elements
+bfuse t_s2 t_s2 t_s3
+bfuse _frontcave t_s1 t_s2
+unifysamedom _frontcave _frontcave
+
+# Cut this cave from the platform
+ttranslate _frontcave $aPlatformLength [expr $aPlatformWidth*2/3] [expr $aPlatformHeight/2]
+bcut _platform _platform _frontcave
+
+tmirror _frontcave $aPlatformLength [expr $aPlatformWidth/2] [expr $aPlatformHeight/2] 0 1 0
+bcut _platform _platform _frontcave
+
+#================================================================================
+# A wedge on the platform
+box t_box  $aPrismXOffset $aPrismYOffset $aPlatformHeight $aPrismLength $aPrismWidth $aPrismHeight
+
+set aCutwedgeLength [expr $aPrismHeight/0.57735]
+wedge _cutwedge $aPlatformLength [expr $aPrismYOffset + $aPrismWidth] $aModelHeight 0 -1 0 -1 0 0 $aCutwedgeLength $aPrismHeight $aPrismWidth 0
+
+bcut _prism t_box _cutwedge
+
+# Make 9 small holes on a top side
+set aWedgeSmallHolesRadius 7.68
+set aWedgeSmallHolesOrbit 67.81
+set aWedgeHoleXPos [expr $aPrismXOffset + 77.5]
+set aWedgeHoleYPos [expr $aPrismYOffset + 77.5]
+
+plane t_plane $aWedgeHoleXPos $aWedgeHoleYPos [expr $aPlatformHeight + $aPrismHeight/2] 0 0 1 1 0 0
+pcylinder t_cyl t_plane $aWedgeSmallHolesRadius [expr $aPrismHeight/2]
+
+set i 2
+while {$i <= 10} {ttranslate t_cyl [expr $aWedgeSmallHolesOrbit*cos($i*$my_pi/6)] [expr $aWedgeSmallHolesOrbit*sin($i*$my_pi/6)] 0; bcut _prism _prism t_cyl; reset t_cyl; incr i}
+
+# Make a cylinder on a canted side
+set aWedgeCylinderRadius 38.75
+set aWedgeCylinderHeight 38.75
+set aWedgeCantedHeight [expr tan($my_pi/6)*($aCutwedgeLength - 69.75)]
+set aWedgeCylinderZPos [expr $aModelHeight - $aWedgeCantedHeight/2]
+plane t_plane [expr $aPrismXOffset + $aPrismLength*3/4] [expr $aPrismYOffset + $aPrismWidth/2] $aWedgeCylinderZPos cos($my_pi/3) 0 sin($my_pi/3) 0 1 0
+pcylinder t_cyl t_plane $aWedgeCylinderRadius $aWedgeCylinderHeight
+explode t_cyl e
+blend t_cyl t_cyl 3 t_cyl_1
+bfuse _prism _prism t_cyl
+unifysamedom _prism _prism
+
+# Make a hole in the cylinder on the wedge
+pcylinder t_cyl t_plane [expr $aWedgeCylinderRadius/2] 100
+ttranslate t_cyl [expr -60*cos($my_pi/3)] 0 [expr -60*sin($my_pi/3)]
+bcut _prism _prism t_cyl
+
+# Make a hole on a right side of the wedge
+plane t_plane [expr $aPlatformLength - 162.75] $aPrismYOffset [expr $aModelHeight - $aWedgeCantedHeight] 0 1 0 1 0 0
+pcylinder t_cyl t_plane 13.1 [expr $aPrismWidth/2]
+bcut _prism _prism t_cyl
+
+# Fuse the platform and the prism
+bfuse _model _platform _prism
+
+# Make a pass-through hole
+set aWedgeHoleInnerRadius 38.77
+set aWedgeHoleOuterRadius 58.13
+set aWedgeHoleBottomInnerRadius 50.38
+
+# Cylinders from bottom to top
+plane t_plane $aWedgeHoleXPos $aWedgeHoleYPos 0
+pcylinder t_cyl1 t_plane $aWedgeHoleOuterRadius 10
+pcylinder t_cyl2 t_plane $aWedgeHoleBottomInnerRadius 10
+pcylinder t_cyl3 t_plane $aWedgeHoleInnerRadius [expr $aModelHeight - 30]
+pcylinder t_cyl4 t_plane $aWedgeHoleOuterRadius 10
+
+ttranslate t_cyl2 0 0 10
+ttranslate t_cyl3 0 0 20
+ttranslate t_cyl4 0 0 [expr $aModelHeight - 10]
+
+bfuse _cutCylindricShape t_cyl1 t_cyl2
+bfuse _cutCylindricShape _cutCylindricShape t_cyl3
+bfuse _cutCylindricShape _cutCylindricShape t_cyl4
+
+bcut _model _model _cutCylindricShape
+
+# Add a block on left side
+circle t_circle1 0 0 38.75
+circle t_circle2 [expr 38.75 + 9.3] [expr -57.35 + 9.3] 9.3
+circle t_circle3 [expr -38.75 - 9.3] [expr -57.35 + 9.3] 9.3
+
+lintan t_l t_circle1 t_circle2
+trim t_line12 t_l_2 0 48.050000000000004
+
+lintan t_l t_circle2 t_circle3
+trim t_line23 t_l_3 0 96.099999999999994
+
+lintan t_l t_circle3 t_circle1
+trim t_line31 t_l_4 0 48.050000000000004
+
+trim t_circle1 t_circle1 0 $my_pi
+trim t_circle2 t_circle2 $my_pi 4.7123889803846897
+trim t_circle3 t_circle3 4.7123889803846897 6.2831853071795862
+
+reverse t_circle1
+
+plane t_plane [expr $aPrismXOffset + 77.5] [expr $aPrismYOffset + $aPrismWidth] [expr $aPlatformHeight + 57.35] 0 1 0 -1 0 0
+
+to3d t_circle1 t_circle1 t_plane
+to3d t_circle2 t_circle2 t_plane
+to3d t_circle3 t_circle3 t_plane
+to3d t_line12 t_line12 t_plane
+to3d t_line23 t_line23 t_plane
+to3d t_line31 t_line31 t_plane
+
+mkedge t_e1 t_circle1
+mkedge t_e2 t_line31
+mkedge t_e3 t_circle3
+mkedge t_e4 t_line23
+mkedge t_e5 t_circle2
+mkedge t_e6 t_line12
+
+wire t_w t_e1 t_e2 t_e3 t_e4 t_e5 t_e6
+mkplane t_f t_w
+prism t_s t_f 0 $aCaveDepth 0
+
+bfuse _model _model t_s
+
+############# Analyse #############
+
+tcopy _model _copy
+trotate _copy $aWedgeHoleXPos $aWedgeHoleYPos 0 0 0 1 90
+bcommon res _model _copy
+checkshape res
+
+unifysamedom r res
+incmesh r 0.1
+trinfo r
+
+set info [trinfo r]
+regexp { +([-0-9.+eE]+) +triangles} $info full tr
+regexp { +([-0-9.+eE]+) +nodes} $info full nd
+regexp { +([-0-9.+eE]+) +nodes} $info full nd
+regexp {Maximal deflection +([-0-9.+eE]+)} $info full defl
+
+set expected_defl 0.04
+set tol_abs_defl 0.01
+set tol_rel_defl 0.01
+checkreal "Maximal deflection" ${defl} ${expected_defl} ${tol_abs_defl} ${tol_rel_defl}
+
+vinit
+vsetdispmode 1
+vdisplay r
+vfit
+set only_screen 1