Visualize OCC shape in Open Inventor

Hello,
I’ve tried to visualize a TopoDS_Shape in Open Inventor, transforming every face of my shape in a nurbs surface. I used the following code to do that, and it works if my shape is a prism, while if my shape is a sphere or a cone, it doesn’t work. I get a strange surface.
What’s wrong? Please help me.

I get this code from “OpenCASCADE BRep viewer” project (http://projects.opencascade.org/projects/graphperf/coin3d.htm).

In this code there's also an algorithm to mesh every surface of the shape, but I need to transform the shape in a set of nurbs surface. So I can check if the surface is flat, checkig if the control points are complanar...

This is the shape2nurbs code:

void occShape2OIVNurbs(TopoDS_Shape myShape, SoSeparator *solidSep) {

//-----------------------
// Use OpenGL NURBS
//-----------------------

TopExp_Explorer ex;
for (ex.Init(myShape, TopAbs_FACE); ex.More(); ex.Next()) {

float* mySurfaceVKnots;
float* mySurfaceUKnots;
int myNbVKnots;
int myNbUKnots;

const TopoDS_Face& aFace = TopoDS::Face(ex.Current());
Handle(Geom_Surface) aGeomSurface = BRep_Tool::Surface(aFace);
Handle(Geom_BSplineSurface) aBSplineSurface;
Standard_Boolean ok = false;
if(aGeomSurface->DynamicType() != STANDARD_TYPE(Geom_BSplineSurface)) {
// try to convert into nurbs
BRepBuilderAPI_NurbsConvert nbscv;
nbscv.Perform(aFace);
if (nbscv.IsDone()){
aGeomSurface = BRep_Tool::Surface(TopoDS::Face(nbscv.Shape()));
ok = true;
}
}
else ok = true;

if(ok) {
aBSplineSurface = Handle(Geom_BSplineSurface)::DownCast(aGeomSurface);

int myNbUPoles = aBSplineSurface->NbUPoles();
int myNbVPoles = aBSplineSurface->NbVPoles();

TColgp_Array2OfPnt aPoles(1, myNbVPoles, 1, myNbUPoles);

TColStd_Array1OfReal aVKnots(1, aBSplineSurface->NbVKnots());
TColStd_Array1OfReal aUKnots(1, aBSplineSurface->NbUKnots());

aBSplineSurface->Poles(aPoles);
aBSplineSurface->UKnots(aUKnots);
aBSplineSurface->VKnots(aVKnots);

//Push the nurbs in Coin3d

// Control Point
Standard_Integer i, j, aCounter;
int aLength = myNbVPoles*myNbUPoles; //Create array of control points and their weights

SbVec4f* mySurfaceCtrlPoints = new SbVec4f[aLength];
if(mySurfaceCtrlPoints == NULL) return;

aCounter = -1;

for(j = 1; j for(i = 1; i const gp_Pnt& aPoint = aBSplineSurface->Pole(i, j); //Control point (U,V)
mySurfaceCtrlPoints[++aCounter].setValue((float)(aPoint.X()),(float)(aPoint.Y()),(float)(aPoint.Z()),(float)(aBSplineSurface->Weight(i, j)));
}
}

TColStd_ListOfReal aListOfKnot;
TColStd_ListIteratorOfListOfReal aListOfKnotIterator;

try {
//Fill the knot`s array taking into account multiplicities
// VKnots
for(i = aVKnots.Lower(); i for(j = 1; jVMultiplicity(i); j++)
aListOfKnot.Append(aVKnots(i));
}

mySurfaceVKnots = new float[aListOfKnot.Extent()];
if(mySurfaceVKnots == NULL) return;

aCounter = -1;
for(aListOfKnotIterator.Initialize(aListOfKnot); aListOfKnotIterator.More(); aListOfKnotIterator.Next()) {
mySurfaceVKnots[++aCounter] = (float)(aListOfKnotIterator.Value());
}
myNbVKnots = aCounter+1;

// UKnots
aListOfKnot.Clear();
for(i = aUKnots.Lower(); i for(j = 1; jUMultiplicity(i); j++)
aListOfKnot.Append(aUKnots(i));
}

mySurfaceUKnots = new float[aListOfKnot.Extent()];
if(mySurfaceUKnots == NULL) return;

aCounter = -1;
for(aListOfKnotIterator.Initialize(aListOfKnot); aListOfKnotIterator.More(); aListOfKnotIterator.Next()) {
mySurfaceUKnots[++aCounter] = (float)(aListOfKnotIterator.Value());
}
myNbUKnots = aCounter+1;
}
catch(Standard_Failure) {
continue;
}

//Nurbs definition
SoNurbsSurface* surface = new SoNurbsSurface;
SoCoordinate4 *controlPts = new SoCoordinate4;
SoComplexity *comp = new SoComplexity;
comp->type.setValue(SoComplexity::OBJECT_SPACE);
comp->value = 0.5;
controlPts->point.setValues(0,aLength,mySurfaceCtrlPoints);
surface->numUControlPoints.setValue(myNbUPoles);
surface->numVControlPoints.setValue(myNbVPoles);
surface->uKnotVector.setValues(0, myNbUKnots, mySurfaceUKnots);
surface->vKnotVector.setValues(0, myNbVKnots, mySurfaceVKnots);
solidSep->addChild(comp);
solidSep->addChild(controlPts);
solidSep->addChild(surface);

delete [] mySurfaceVKnots;
delete [] mySurfaceUKnots;

}
}
}