0025591: Command mkshell produces wrong shell

The functionality to decide, whether the edge is degenerated, was shared via BRepLib_MakeFace. The verification of producing degenerated edges was added to BRepLib_MakeShell.

Test case for issue CR25591

src/BRepLib/BRepLib_MakeFace.cdl

@@ -48,6 +48,7 @@ uses
     Cone      from gp,
     Sphere    from gp,
     Torus     from gp,
+    Curve     from Geom,
     Surface   from Geom,
     Face      from TopoDS,
     Wire      from TopoDS,
@@ -258,6 +259,18 @@ is
     	NotDone from StdFail
     is static;
     
+
+    IsDegenerated (myclass;
+                   theCurve  :        Curve from Geom;
+                   theMaxTol :        Real  from Standard;
+                   theActTol : in out Real  from Standard)
+    returns Boolean;
+        --- Purpose: Checks the specified curve is degenerated 
+        --           according to specified tolerance.
+        --           Returns <theActTol> less than <theMaxTol>, which shows
+        --           actual tolerance to decide the curve is degenerated.
+        --  Warning: For internal use of BRepLib_MakeFace and BRepLib_MakeShell.
+
 fields
     myError    : FaceError from BRepLib;
 end MakeFace;

src/BRepLib/BRepLib_MakeFace.cxx

@@ -427,7 +427,8 @@ void  BRepLib_MakeFace::Init(const Handle(Geom_Surface)& S,
 //           passed tolerance value
 //=======================================================================
 
-static Standard_Boolean IsDegenerated(const Handle(Geom_Curve)& theCurve,
+Standard_Boolean BRepLib_MakeFace::IsDegenerated(
+    const Handle(Geom_Curve)& theCurve,
     const Standard_Real       theMaxTol,
           Standard_Real&      theActTol)
 {

src/BRepLib/BRepLib_MakeShell.cxx

@@ -17,6 +17,7 @@
 #include <BRepLib_MakeShell.ixx>
 
 #include <BRepLib.hxx>
+#include <BRepLib_MakeFace.hxx>
 #include <Precision.hxx>
 #include <TColStd_Array1OfReal.hxx>
 
@@ -35,6 +36,8 @@
 #include <TopTools_Array1OfShape.hxx>
 #include <BRep_Builder.hxx>
 
+#include <TopExp_Explorer.hxx>
+
 
 //=======================================================================
 //function : BRepLib_MakeShell
@@ -355,6 +358,20 @@ void BRepLib_MakeShell::Init(const Handle(Geom_Surface)& S,
   BRepLib::EncodeRegularity(myShape);
   myShape.Closed (BRep_Tool::IsClosed (myShape));
 
+  // Additional checking for degenerated edges
+  Standard_Boolean isDegenerated;
+  Standard_Real aFirst, aLast;
+  Standard_Real aTol = Precision::Confusion();
+  Standard_Real anActTol;
+  TopExp_Explorer anExp(myShape, TopAbs_EDGE);
+  for ( ; anExp.More(); anExp.Next())
+  {
+    const TopoDS_Edge& anEdge = TopoDS::Edge(anExp.Current());
+    Handle(Geom_Curve) aCurve = BRep_Tool::Curve(anEdge, aFirst, aLast);
+    isDegenerated = BRepLib_MakeFace::IsDegenerated(aCurve, aTol, anActTol);
+    B.Degenerated(anEdge, isDegenerated);
+  }
+  
   myError = BRepLib_ShellDone;
   Done();
 }

tests/bugs/modalg_5/bug25591

@@ -0,0 +1,18 @@
+puts "============"
+puts "OCC25591"
+puts "============"
+puts ""
+#################################
+# Command mkshell produces wrong shell
+#################################
+
+sphere surf 100
+mkshell sh surf 1 
+explode sh e
+catch {mkcurve csh_2 sh_2}
+
+if { [llength [dump csh_2]] > 0 } {
+  puts "Error: Command mkshell produces wrong shell"
+} else {
+  puts "OK: Command mkshell produces good shell"
+}