some optimization ( StdPrs_ToolRFace)

instead of

void StdPrs_ToolRFace::Next()
{
myExplorer.Next();

if (myExplorer.More()) {
// skip INTERNAL and EXTERNAL edges
if (myExplorer.Current().Orientation() == TopAbs_INTERNAL) Next();
if (myExplorer.Current().Orientation() == TopAbs_EXTERNAL) Next();
if (myExplorer.More()) {
Standard_Real U1,U2;
const Handle(Geom2d_Curve)& C =
BRep_Tool::CurveOnSurface(TopoDS::Edge(myExplorer.Current()),
myFace,
U1,U2);
#ifdef OCC316
if ( !C.IsNull() )
#endif
DummyCurve.Load(C,U1,U2);
}
}
}

it looks much better as: (less stack usage)

void StdPrs_ToolRFace::Next()
{
myExplorer.Next();

if (myExplorer.More()) {
// skip INTERNAL and EXTERNAL edges
while (myExpolrer.More() && (myExplorer.Current().Orientation() == TopAbs_INTERNAL || myExplorer.Current().Orientation() == TopAbs_EXTERNAL)) myExplorer.Next();
if (myExplorer.More()) {
Standard_Real U1,U2;
const Handle(Geom2d_Curve)& C =
BRep_Tool::CurveOnSurface(TopoDS::Edge(myExplorer.Current()),
myFace,
U1,U2);
#ifdef OCC316
if ( !C.IsNull() )
#endif
DummyCurve.Load(C,U1,U2);
}
}
}

at least i'd prefer the second code.