src/GeomAPI/GeomAPI_Circ2d.cpp

   1 // Copyright (C) 2014-20xx CEA/DEN, EDF R&D
   2
   3 // File:        GeomAPI_Circ2d.cpp
   4 // Created:     29 May 2014
   5 // Author:      Artem ZHIDKOV
   6
   7 #include <GeomAPI_Circ2d.h>
   8 #include <GeomAPI_Ax3.h>
   9 #include <GeomAPI_Pnt2d.h>
  10 #include <GeomAPI_Dir2d.h>
  11 #include <GeomAPI_Shape.h>
  12
  13 #include <BRep_Tool.hxx>
  14 #include <gp_Dir2d.hxx>
  15 #include <gp_Circ2d.hxx>
  16 #include <gp_Lin2d.hxx>
  17 #include <gp_Pnt2d.hxx>
  18 #include <gp_Ax2d.hxx>
  19 #include <GccAna_Circ2d3Tan.hxx>
  20 #include <GccAna_Circ2dTanCen.hxx>
  21 #include <GccEnt.hxx>
  22 #include <GccEnt_QualifiedCirc.hxx>
  23 #include <GccEnt_QualifiedLin.hxx>
  24 #include <GeomLib_Tool.hxx>
  25 #include <Geom2d_Circle.hxx>
  26 #include <Geom2dAPI_ProjectPointOnCurve.hxx>
  27 #include <Geom_Plane.hxx>
  28 #include <IntAna2d_AnaIntersection.hxx>
  29 #include <Precision.hxx>
  30 #include <TopoDS.hxx>
  31 #include <TopoDS_Edge.hxx>
  32
  33 #include <vector>
  34
  35 #define MY_CIRC2D implPtr<gp_Circ2d>()
  36
  37 typedef std::shared_ptr<Geom2dAdaptor_Curve>  CurveAdaptorPtr;
  38
  39 class CircleBuilder
  40 {
  41 public:
  42   CircleBuilder(const std::shared_ptr<GeomAPI_Ax3>& theBasePlane)
  43     : myPlane(new Geom_Plane(theBasePlane->impl<gp_Ax3>()))
  44   {}
  45
  46   void addCenter(const std::shared_ptr<GeomAPI_Pnt2d>& theCenter)
  47   { myCenter = theCenter; }
  48
  49   void addPassingEntity(const std::shared_ptr<GeomAPI_Interface>& theEntity)
  50   {
  51     std::shared_ptr<GeomAPI_Pnt2d> aPoint = std::dynamic_pointer_cast<GeomAPI_Pnt2d>(theEntity);
  52     if (aPoint)
  53       addPassingPoint(aPoint);
  54     else {
  55       std::shared_ptr<GeomAPI_Shape> aShape = std::dynamic_pointer_cast<GeomAPI_Shape>(theEntity);
  56       if (aShape)
  57         addTangentCurve(aShape);
  58     }
  59   }
  60
  61   void addTangentCurve(const std::shared_ptr<GeomAPI_Shape>& theEdge)
  62   {
  63     if (!theEdge->isEdge())
  64       return;
  65
  66     const TopoDS_Edge& anEdge = TopoDS::Edge(theEdge->impl<TopoDS_Shape>());
  67
  68     double aFirst, aLast;
  69     TopLoc_Location aLoc;
  70     CurveAdaptorPtr aCurve(new Geom2dAdaptor_Curve(
  71         BRep_Tool::CurveOnSurface(anEdge, myPlane, aLoc, aFirst, aLast)));
  72
  73     myTangentShapes.push_back(aCurve);
  74   }
  75
  76   void addPassingPoint(const std::shared_ptr<GeomAPI_Pnt2d>& thePoint)
  77   {
  78     myPassingPoints.push_back(thePoint->impl<gp_Pnt2d>());
  79   }
  80
  81   gp_Circ2d* circle()
  82   {
  83     gp_Circ2d* aResult = 0;
  84     if (myCenter) {
  85       if (myPassingPoints.size() == 1)
  86         aResult = circleByCenterAndPassingPoint();
  87       else if (myTangentShapes.size() == 1)
  88         aResult = circleByCenterAndTangent();
  89     } else {
  90       switch (myPassingPoints.size()) {
  91       case 0:
  92         aResult = circleByThreeTangentCurves();
  93         break;
  94       case 1:
  95         aResult = circleByPointAndTwoTangentCurves();
  96         break;
  97       case 2:
  98         aResult = circleByTwoPointsAndTangentCurve();
  99         break;
 100       case 3:
 101         aResult = circleByThreePassingPoints();
 102         break;
 103       default:
 104         break;
 105       }
 106     }
 107     return aResult;
 108   }
 109
 110 private:
 111   gp_Circ2d* circleByCenterAndPassingPoint()
 112   {
 113     const gp_Pnt2d& aCenter = myCenter->impl<gp_Pnt2d>();
 114     GccAna_Circ2dTanCen aBuilder(myPassingPoints[0], aCenter);
 115     if (aBuilder.NbSolutions() > 0)
 116       return new gp_Circ2d(aBuilder.ThisSolution(1));
 117     return 0;
 118   }
 119
 120   gp_Circ2d* circleByCenterAndTangent()
 121   {
 122     const gp_Pnt2d& aCenter = myCenter->impl<gp_Pnt2d>();
 123     CurveAdaptorPtr aCurve = myTangentShapes[0];
 124
 125     std::shared_ptr<GccAna_Circ2dTanCen> aCircleBuilder;
 126     if (aCurve->GetType() == GeomAbs_Line) {
 127       aCircleBuilder = std::shared_ptr<GccAna_Circ2dTanCen>(
 128           new GccAna_Circ2dTanCen(aCurve->Line(), aCenter));
 129     } else if (aCurve->GetType() == GeomAbs_Circle) {
 130       aCircleBuilder = std::shared_ptr<GccAna_Circ2dTanCen>(new GccAna_Circ2dTanCen(
 131           GccEnt::Unqualified(aCurve->Circle()), aCenter, Precision::Confusion()));
 132     }
 133
 134     return getProperCircle(aCircleBuilder);
 135   }
 136
 137   gp_Circ2d* getProperCircle(const std::shared_ptr<GccAna_Circ2dTanCen>& theBuilder) const
 138   {
 139     if (!theBuilder)
 140       return 0;
 141
 142     CurveAdaptorPtr aCurve = myTangentShapes[0];
 143
 144     gp_Circ2d* aResult = 0;
 145     int aNbSol = theBuilder->NbSolutions();
 146     double aParSol, aPonTgCurve;
 147     gp_Pnt2d aTgPnt;
 148     for (int i = 1; i <= aNbSol && aCurve; ++i) {
 149       theBuilder->Tangency1(i, aParSol, aPonTgCurve, aTgPnt);
 150       if (aPonTgCurve >= aCurve->FirstParameter() && aPonTgCurve <= aCurve->LastParameter()) {
 151         aResult = new gp_Circ2d(theBuilder->ThisSolution(i));
 152         break;
 153       }
 154     }
 155     // unable to build circle passing through the tangent curve,
 156     // so get a circle passing any tangent point
 157     if (!aResult && aNbSol > 0)
 158       aResult =  new gp_Circ2d(theBuilder->ThisSolution(1));
 159     return aResult;
 160   }
 161
 162
 163   gp_Circ2d* circleByThreeTangentCurves()
 164   {
 165     std::shared_ptr<GccEnt_QualifiedCirc> aTgCirc[3];
 166     std::shared_ptr<GccEnt_QualifiedLin>  aTgLine[3];
 167     int aNbTgCirc = 0;
 168     int aNbTgLine = 0;
 169
 170     std::vector<CurveAdaptorPtr>::iterator anIt = myTangentShapes.begin();
 171     for (; anIt != myTangentShapes.end(); ++anIt) {
 172       switch ((*anIt)->GetType()) {
 173       case GeomAbs_Line:
 174         aTgLine[aNbTgLine++] = std::shared_ptr<GccEnt_QualifiedLin>(
 175             new GccEnt_QualifiedLin((*anIt)->Line(), GccEnt_unqualified));
 176         break;
 177       case GeomAbs_Circle:
 178         aTgCirc[aNbTgCirc++] = std::shared_ptr<GccEnt_QualifiedCirc>(
 179             new GccEnt_QualifiedCirc((*anIt)->Circle(), GccEnt_unqualified));
 180         break;
 181       default:
 182         break;
 183       }
 184     }
 185     if (aNbTgCirc + aNbTgLine != 3)
 186       return 0;
 187
 188     std::shared_ptr<GccAna_Circ2d3Tan> aCircleBuilder;
 189     switch (aNbTgLine) {
 190     case 0:
 191       aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(new GccAna_Circ2d3Tan(
 192           *aTgCirc[0], *aTgCirc[1], *aTgCirc[2], Precision::Confusion()));
 193       break;
 194     case 1:
 195       aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(new GccAna_Circ2d3Tan(
 196           *aTgCirc[0], *aTgCirc[1], *aTgLine[0], Precision::Confusion()));
 197       break;
 198     case 2:
 199       aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(new GccAna_Circ2d3Tan(
 200           *aTgCirc[0], *aTgLine[0], *aTgLine[1], Precision::Confusion()));
 201       break;
 202     case 3:
 203       aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(new GccAna_Circ2d3Tan(
 204           *aTgLine[0], *aTgLine[1], *aTgLine[0], Precision::Confusion()));
 205       break;
 206     default:
 207       break;
 208     }
 209
 210     return getProperCircle(aCircleBuilder);
 211   }
 212
 213   gp_Circ2d* circleByPointAndTwoTangentCurves()
 214   {
 215     const gp_Pnt2d& aPoint = myPassingPoints[0];
 216     CurveAdaptorPtr aCurve1 = myTangentShapes[0];
 217     CurveAdaptorPtr aCurve2 = myTangentShapes[1];
 218     if (!aCurve1 || !aCurve2)
 219       return 0;
 220
 221     std::shared_ptr<GccAna_Circ2d3Tan> aCircleBuilder;
 222     if (aCurve1->GetType() == GeomAbs_Line) {
 223       if (aCurve2->GetType() == GeomAbs_Line) {
 224         aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(
 225             new GccAna_Circ2d3Tan(GccEnt::Unqualified(aCurve1->Line()),
 226                                   GccEnt::Unqualified(aCurve2->Line()),
 227                                   aPoint, Precision::Confusion()));
 228       } else if (aCurve2->GetType() == GeomAbs_Circle) {
 229         aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(
 230             new GccAna_Circ2d3Tan(GccEnt::Unqualified(aCurve2->Circle()),
 231                                   GccEnt::Unqualified(aCurve1->Line()),
 232                                   aPoint, Precision::Confusion()));
 233       }
 234     } else if (aCurve1->GetType() == GeomAbs_Circle) {
 235       if (aCurve2->GetType() == GeomAbs_Line) {
 236         aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(
 237             new GccAna_Circ2d3Tan(GccEnt::Unqualified(aCurve1->Circle()),
 238                                   GccEnt::Unqualified(aCurve2->Line()),
 239                                   aPoint, Precision::Confusion()));
 240       } else if (aCurve2->GetType() == GeomAbs_Circle) {
 241         aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(
 242             new GccAna_Circ2d3Tan(GccEnt::Unqualified(aCurve2->Circle()),
 243                                   GccEnt::Unqualified(aCurve1->Circle()),
 244                                   aPoint, Precision::Confusion()));
 245       }
 246     }
 247
 248     return getProperCircle(aCircleBuilder);
 249   }
 250
 251   gp_Circ2d* circleByTwoPointsAndTangentCurve()
 252   {
 253     const gp_Pnt2d& aPoint1 = myPassingPoints[0];
 254     const gp_Pnt2d& aPoint2 = myPassingPoints[1];
 255     CurveAdaptorPtr aCurve = myTangentShapes[0];
 256     if (!aCurve)
 257       return 0;
 258
 259     std::shared_ptr<GccAna_Circ2d3Tan> aCircleBuilder;
 260     if (aCurve->GetType() == GeomAbs_Line) {
 261       aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(new GccAna_Circ2d3Tan(
 262         GccEnt::Unqualified(aCurve->Line()), aPoint1, aPoint2, Precision::Confusion()));
 263     } else if (aCurve->GetType() == GeomAbs_Circle) {
 264       aCircleBuilder = std::shared_ptr<GccAna_Circ2d3Tan>(new GccAna_Circ2d3Tan(
 265           GccEnt::Unqualified(aCurve->Circle()), aPoint1, aPoint2, Precision::Confusion()));
 266     }
 267
 268     return getProperCircle(aCircleBuilder);
 269   }
 270
 271   gp_Circ2d* circleByThreePassingPoints()
 272   {
 273     GccAna_Circ2d3Tan aCircleBuilder(myPassingPoints[0],
 274                                      myPassingPoints[1],
 275                                      myPassingPoints[2],
 276                                      Precision::Confusion());
 277     if (aCircleBuilder.NbSolutions() > 0)
 278       return new gp_Circ2d(aCircleBuilder.ThisSolution(1));
 279     return 0;
 280   }
 281
 282
 283   gp_Circ2d* getProperCircle(const std::shared_ptr<GccAna_Circ2d3Tan>& theBuilder) const
 284   {
 285     if (!theBuilder)
 286       return 0;
 287
 288     gp_Circ2d* aResult = 0;
 289     int aNbSol = theBuilder->NbSolutions();
 290     double aParSol, aPonTgCurve;
 291     gp_Pnt2d aTgPnt;
 292     for (int i = 1; i <= aNbSol; ++i) {
 293       bool isApplicable = false;
 294       if (myTangentShapes.size() >= 1) {
 295         theBuilder->Tangency1(i, aParSol, aPonTgCurve, aTgPnt);
 296         isApplicable = aPonTgCurve >= myTangentShapes[0]->FirstParameter() &&
 297                        aPonTgCurve <= myTangentShapes[0]->LastParameter();
 298       }
 299       if (myTangentShapes.size() >= 2 && isApplicable) {
 300         theBuilder->Tangency2(i, aParSol, aPonTgCurve, aTgPnt);
 301         isApplicable = aPonTgCurve >= myTangentShapes[1]->FirstParameter() &&
 302                        aPonTgCurve <= myTangentShapes[1]->LastParameter();
 303       }
 304       if (myTangentShapes.size() >= 3 && isApplicable) {
 305         theBuilder->Tangency3(i, aParSol, aPonTgCurve, aTgPnt);
 306         isApplicable = aPonTgCurve >= myTangentShapes[2]->FirstParameter() &&
 307                        aPonTgCurve <= myTangentShapes[2]->LastParameter();
 308       }
 309
 310       if (isApplicable) {
 311         aResult = new gp_Circ2d(theBuilder->ThisSolution(i));
 312         break;
 313       }
 314     }
 315     // unable to build circle passing through the tangent curve => get any tangent point
 316     if (!aResult && aNbSol > 0)
 317       aResult =  new gp_Circ2d(theBuilder->ThisSolution(1));
 318     return aResult;
 319   }
 320
 321 private:
 322   Handle(Geom_Plane) myPlane;
 323   std::shared_ptr<GeomAPI_Pnt2d> myCenter;
 324   std::vector<gp_Pnt2d> myPassingPoints;
 325   std::vector<CurveAdaptorPtr> myTangentShapes;
 326 };
 327
 328 typedef std::shared_ptr<CircleBuilder> CircleBuilderPtr;
 329
 330
 331 static gp_Circ2d* newCirc2d(const double theCenterX, const double theCenterY, const gp_Dir2d theDir,
 332                             const double theRadius)
 333 {
 334   gp_Pnt2d aCenter(theCenterX, theCenterY);
 335   return new gp_Circ2d(gp_Ax2d(aCenter, theDir), theRadius);
 336 }
 337
 338 static gp_Circ2d* newCirc2d(const double theCenterX, const double theCenterY,
 339                             const double thePointX, const double thePointY)
 340 {
 341   gp_Pnt2d aCenter(theCenterX, theCenterY);
 342   gp_Pnt2d aPoint(thePointX, thePointY);
 343
 344   double aRadius = aCenter.Distance(aPoint);
 345
 346   if (aCenter.IsEqual(aPoint, Precision::Confusion()))
 347     return NULL;
 348
 349   gp_Dir2d aDir(thePointX - theCenterX, thePointY - theCenterY);
 350
 351   return newCirc2d(theCenterX, theCenterY, aDir, aRadius);
 352 }
 353
 354 static gp_Circ2d* newCirc2d(const std::shared_ptr<GeomAPI_Pnt2d>& theFirstPoint,
 355                             const std::shared_ptr<GeomAPI_Pnt2d>& theSecondPoint,
 356                             const std::shared_ptr<GeomAPI_Pnt2d>& theThirdPoint)
 357 {
 358   gp_XY aFirstPnt(theFirstPoint->x(), theFirstPoint->y());
 359   gp_XY aSecondPnt(theSecondPoint->x(), theSecondPoint->y());
 360   gp_XY aThirdPnt(theThirdPoint->x(), theThirdPoint->y());
 361
 362   gp_XY aVec12 = aSecondPnt - aFirstPnt;
 363   gp_XY aVec23 = aThirdPnt - aSecondPnt;
 364   gp_XY aVec31 = aFirstPnt - aThirdPnt;
 365
 366   // coefficients to calculate center
 367   double aCoeff1, aCoeff2, aCoeff3;
 368
 369   // square of parallelogram
 370   double aSquare2 = aVec12.Crossed(aVec23);
 371   aSquare2 *= aSquare2 * 2.0;
 372   if (aSquare2 < 1.e-20) {
 373     // if two points are equal, build a circle on two different points as on diameter
 374     double aSqLen12 = aVec12.SquareModulus();
 375     double aSqLen23 = aVec23.SquareModulus();
 376     double aSqLen31 = aVec31.SquareModulus();
 377     if (aSqLen12 < Precision::SquareConfusion() &&
 378         aSqLen23 < Precision::SquareConfusion() &&
 379         aSqLen31 < Precision::SquareConfusion())
 380       return NULL;
 381     aCoeff1 = aCoeff2 = aCoeff3 = 1.0 / 3.0;
 382   }
 383   else {
 384     aCoeff1 = aVec23.Dot(aVec23) / aSquare2 * aVec12.Dot(aVec31.Reversed());
 385     aCoeff2 = aVec31.Dot(aVec31) / aSquare2 * aVec23.Dot(aVec12.Reversed());
 386     aCoeff3 = aVec12.Dot(aVec12) / aSquare2 * aVec31.Dot(aVec23.Reversed());
 387   }
 388   // center
 389   gp_XY aCenter = aFirstPnt * aCoeff1 + aSecondPnt * aCoeff2 + aThirdPnt * aCoeff3;
 390   // radius
 391   double aRadius = (aFirstPnt - aCenter).Modulus();
 392
 393   gp_Dir2d aDir(aFirstPnt - aCenter);
 394   return newCirc2d(aCenter.X(), aCenter.Y(), aDir, aRadius);
 395 }
 396
 397
 398
 399 GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theCenter,
 400                                const std::shared_ptr<GeomAPI_Pnt2d>& theCirclePoint)
 401     : GeomAPI_Interface(
 402         newCirc2d(theCenter->x(), theCenter->y(), theCirclePoint->x(), theCirclePoint->y()))
 403 {
 404 }
 405
 406 GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theCenter,
 407                                const std::shared_ptr<GeomAPI_Dir2d>& theDir, double theRadius)
 408     : GeomAPI_Interface(
 409         newCirc2d(theCenter->x(), theCenter->y(), theDir->impl<gp_Dir2d>(), theRadius))
 410 {
 411 }
 412
 413 GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theFirstPoint,
 414                                const std::shared_ptr<GeomAPI_Pnt2d>& theSecondPoint,
 415                                const std::shared_ptr<GeomAPI_Pnt2d>& theThirdPoint)
 416     : GeomAPI_Interface(newCirc2d(theFirstPoint, theSecondPoint, theThirdPoint))
 417 {
 418 }
 419
 420 GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theCenter,
 421                                const std::shared_ptr<GeomAPI_Shape>& theTangent,
 422                                const std::shared_ptr<GeomAPI_Ax3>&   thePlane)
 423 {
 424   CircleBuilderPtr aBuilder(new CircleBuilder(thePlane));
 425   aBuilder->addCenter(theCenter);
 426   aBuilder->addTangentCurve(theTangent);
 427   setImpl(aBuilder->circle());
 428 }
 429
 430 GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Interface>& theEntity1,
 431                                const std::shared_ptr<GeomAPI_Interface>& theEntity2,
 432                                const std::shared_ptr<GeomAPI_Interface>& theEntity3,
 433                                const std::shared_ptr<GeomAPI_Ax3>&       thePlane)
 434 {
 435   CircleBuilderPtr aBuilder(new CircleBuilder(thePlane));
 436   aBuilder->addPassingEntity(theEntity1);
 437   aBuilder->addPassingEntity(theEntity2);
 438   aBuilder->addPassingEntity(theEntity3);
 439   setImpl(aBuilder->circle());
 440 }
 441
 442
 443 const std::shared_ptr<GeomAPI_Pnt2d> GeomAPI_Circ2d::project(
 444     const std::shared_ptr<GeomAPI_Pnt2d>& thePoint) const
 445 {
 446   std::shared_ptr<GeomAPI_Pnt2d> aResult;
 447   if (!MY_CIRC2D)
 448     return aResult;
 449
 450   const gp_Pnt2d& aCenter = MY_CIRC2D->Location();
 451   const gp_Pnt2d& aPoint = thePoint->impl<gp_Pnt2d>();
 452
 453   double aDist = aCenter.Distance(aPoint);
 454   if (aDist < Precision::Confusion())
 455     return aResult;
 456
 457   if (Abs(aDist - MY_CIRC2D->Radius()) < Precision::Confusion()) {
 458     // Point on the circle
 459     aResult = std::shared_ptr<GeomAPI_Pnt2d>(
 460         new GeomAPI_Pnt2d(thePoint->x(), thePoint->y()));
 461   } else {
 462     gp_Dir2d aDir(aPoint.XY() - aCenter.XY());
 463     gp_XY aNewPoint = aCenter.XY() + aDir.XY() * MY_CIRC2D->Radius();
 464     aResult = std::shared_ptr<GeomAPI_Pnt2d>(
 465         new GeomAPI_Pnt2d(aNewPoint.X(), aNewPoint.Y()));
 466   }
 467
 468   return aResult;
 469 }
 470
 471 const std::shared_ptr<GeomAPI_Pnt2d> GeomAPI_Circ2d::center() const
 472 {
 473   if (!MY_CIRC2D)
 474     return std::shared_ptr<GeomAPI_Pnt2d>();
 475   const gp_Pnt2d& aCenter = MY_CIRC2D->Location();
 476   return std::shared_ptr<GeomAPI_Pnt2d>(new GeomAPI_Pnt2d(aCenter.X(), aCenter.Y()));
 477 }
 478
 479 double GeomAPI_Circ2d::radius() const
 480 {
 481   if (!MY_CIRC2D)
 482     return 0.0;
 483   return MY_CIRC2D->Radius();
 484 }
 485
 486 //=================================================================================================
 487 const bool GeomAPI_Circ2d::parameter(const std::shared_ptr<GeomAPI_Pnt2d> thePoint,
 488                                    const double theTolerance,
 489                                    double& theParameter) const
 490 {
 491   Handle(Geom2d_Circle) aCurve = new Geom2d_Circle(*MY_CIRC2D);
 492   return GeomLib_Tool::Parameter(aCurve, thePoint->impl<gp_Pnt2d>(),
 493                                  theTolerance, theParameter) == Standard_True;
 494 }
 495
 496 //=================================================================================================
 497 void GeomAPI_Circ2d::D0(const double theU, std::shared_ptr<GeomAPI_Pnt2d>& thePoint)
 498 {
 499   Handle(Geom2d_Circle) aCurve = new Geom2d_Circle(*MY_CIRC2D);
 500   gp_Pnt2d aPnt;
 501   aCurve->D0(theU, aPnt);
 502   thePoint.reset(new GeomAPI_Pnt2d(aPnt.X(), aPnt.Y()));
 503 }
 504