X-Git-Url: http://git.salome-platform.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2FSketchPlugin%2FSketchPlugin_Arc.cpp;h=ac9981b002ce4684a3a5921d617f1d7c321bec49;hb=1d23063e3fd8241ef440f0de41d12a03c669aff7;hp=e166608d14d5c0347845dad6aa07d0c79ab6a376;hpb=6b437d84d92c29ba8c2c843735fa2feb4f0664c7;p=modules%2Fshaper.git

diff --git a/src/SketchPlugin/SketchPlugin_Arc.cpp b/src/SketchPlugin/SketchPlugin_Arc.cpp
index e166608d1..ac9981b00 100644
--- a/src/SketchPlugin/SketchPlugin_Arc.cpp
+++ b/src/SketchPlugin/SketchPlugin_Arc.cpp
@@ -1,135 +1,809 @@
+// Copyright (C) 2014-20xx CEA/DEN, EDF R&D -->
+
 // File:        SketchPlugin_Arc.cpp
 // Created:     26 Apr 2014
 // Author:      Artem ZHIDKOV
 
 #include "SketchPlugin_Arc.h"
 #include "SketchPlugin_Sketch.h"
+#include <SketchPlugin_ConstraintCoincidence.h>
+#include <SketchPlugin_ConstraintTangent.h>
+
+#include <Events_Loop.h>
 #include <ModelAPI_Data.h>
+#include <ModelAPI_ResultConstruction.h>
+#include <ModelAPI_AttributeDouble.h>
+#include <ModelAPI_AttributeRefAttr.h>
+#include <ModelAPI_AttributeSelection.h>
+#include <ModelAPI_AttributeString.h>
+#include <ModelAPI_Events.h>
+#include <ModelAPI_Validator.h>
+#include <ModelAPI_Session.h>
 
+#include <GeomAPI_Ax2.h>
 #include <GeomAPI_Circ2d.h>
+#include <GeomAPI_Circ.h>
+#include <GeomAPI_Dir2d.h>
+#include <GeomAPI_Dir.h>
+#include <GeomAPI_Lin2d.h>
+#include <GeomAPI_Lin.h>
 #include <GeomAPI_Pnt2d.h>
-
+#include <GeomAPI_XY.h>
 #include <GeomDataAPI_Point2D.h>
 #include <GeomDataAPI_Dir.h>
-
 #include <GeomAlgoAPI_PointBuilder.h>
 #include <GeomAlgoAPI_EdgeBuilder.h>
 #include <GeomAlgoAPI_CompoundBuilder.h>
+// for sqrt on Linux
+#include <math.h>
 
 const double tolerance = 1e-7;
+const double paramTolerance = 1.e-4;
+const double PI =3.141592653589793238463;
 
-SketchPlugin_Arc::SketchPlugin_Arc()
-  : SketchPlugin_Feature()
-{
+namespace {
+  /*static const std::string& ARC_TYPE()
+  {
+    static const std::string TYPE("ArcType");
+    return TYPE;
+  }*/
+  static const std::string& ARC_TYPE_CENTER_START_END()
+  {
+    static const std::string TYPE("CenterStartEnd");
+    return TYPE;
+  }
+  static const std::string& ARC_TYPE_THREE_POINTS()
+  {
+    static const std::string TYPE("ThreePoints");
+    return TYPE;
+  }
+  /*static const std::string& ARC_TYPE_TANGENT()
+  {
+    static const std::string TYPE("Tangent");
+    return TYPE;
+  }*/
+
+  static const std::string& PASSED_POINT_ID()
+  {
+    static const std::string PASSED_PNT("ArcPassedPoint");
+    return PASSED_PNT;
+  }
+  static const std::string& TANGENT_POINT_ID()
+  {
+    static const std::string TANGENT_PNT("ArcTangentPoint");
+    return TANGENT_PNT;
+  }
+  static const std::string& RADIUS_ID()
+  {
+    static const std::string RADIUS("ArcRadius");
+    return RADIUS;
+  }
+  static const std::string& ANGLE_ID()
+  {
+    static const std::string ANGLE("ArcAngle");
+    return ANGLE;
+  }
+
+  static const std::string& POINT_ID(int theIndex)
+  {
+    switch (theIndex) {
+    case 1: return SketchPlugin_Arc::START_ID();
+    case 2: return SketchPlugin_Arc::END_ID();
+    case 3: return PASSED_POINT_ID();
+    }
+
+    static const std::string DUMMY;
+    return DUMMY;
+  }
 }
 
-void SketchPlugin_Arc::initAttributes()
+
+
+SketchPlugin_Arc::SketchPlugin_Arc()
+    : SketchPlugin_SketchEntity()
 {
-  data()->addAttribute(ARC_ATTR_CENTER, GeomDataAPI_Point2D::type());
-  data()->addAttribute(ARC_ATTR_START,  GeomDataAPI_Point2D::type());
-  data()->addAttribute(ARC_ATTR_END,    GeomDataAPI_Point2D::type());
+  myStartUpdate = false;
+  myEndUpdate = false;
+  // default values
+  myXEndBefore = 0;
+  myYEndBefore = 0;
+
+  myParamBefore = 0;
 }
 
-void SketchPlugin_Arc::execute() 
+void SketchPlugin_Arc::initDerivedClassAttributes()
 {
+  data()->addAttribute(CENTER_ID(), GeomDataAPI_Point2D::typeId());
+  data()->addAttribute(START_ID(), GeomDataAPI_Point2D::typeId());
+  std::shared_ptr<GeomDataAPI_Point2D> anEndAttr = std::dynamic_pointer_cast<
+    GeomDataAPI_Point2D>(data()->addAttribute(END_ID(), GeomDataAPI_Point2D::typeId()));
+  data()->addAttribute(EXTERNAL_ID(), ModelAPI_AttributeSelection::typeId());
+  ModelAPI_Session::get()->validators()->registerNotObligatory(getKind(), EXTERNAL_ID());
+
+  data()->addAttribute(INVERSED_ID(), ModelAPI_AttributeBoolean::typeId());
+  AttributeBooleanPtr isInversed =
+      std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(attribute(INVERSED_ID()));
+  if (!isInversed->isInitialized())
+    isInversed->setValue(false);
+
+  // get the initial values
+  if (anEndAttr->isInitialized()) {
+    myXEndBefore = anEndAttr->x();
+    myYEndBefore = anEndAttr->y();
+  }
+
+  data()->addAttribute(ARC_TYPE(), ModelAPI_AttributeString::typeId());
+  std::dynamic_pointer_cast<ModelAPI_AttributeString>(
+      data()->attribute(ARC_TYPE()))->setValue(ARC_TYPE_CENTER_START_END());
+
+  data()->addAttribute(PASSED_POINT_ID(), GeomDataAPI_Point2D::typeId());
+  data()->addAttribute(TANGENT_POINT_ID(), ModelAPI_AttributeRefAttr::typeId());
+  data()->addAttribute(RADIUS_ID(), ModelAPI_AttributeDouble::typeId());
+  data()->addAttribute(ANGLE_ID(), ModelAPI_AttributeDouble::typeId());
+
+  ModelAPI_Session::get()->validators()->registerNotObligatory(getKind(), RADIUS_ID());
+  ModelAPI_Session::get()->validators()->registerNotObligatory(getKind(), ANGLE_ID());
 }
 
-const boost::shared_ptr<GeomAPI_Shape>& SketchPlugin_Arc::preview()
+void SketchPlugin_Arc::execute()
 {
   SketchPlugin_Sketch* aSketch = sketch();
-  if (aSketch) {
-    std::list<boost::shared_ptr<GeomAPI_Shape> > aShapes;
+  // result for the arc is set only when all obligatory attributes are initialized,
+  // otherwise AIS object is used to visualize the arc's preview
+  if (aSketch && isFeatureValid()) {
+    ResultPtr aLastResult = lastResult();
+    bool hasResult = aLastResult && aLastResult.get();
 
     // compute a circle point in 3D view
-    boost::shared_ptr<GeomDataAPI_Point2D> aCenterAttr = 
-      boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(data()->attribute(ARC_ATTR_CENTER));
-      // compute the arc start point
-      boost::shared_ptr<GeomDataAPI_Point2D> aStartAttr = 
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(data()->attribute(ARC_ATTR_START));
-      if (aCenterAttr->isInitialized() && aStartAttr->isInitialized()) {
-      boost::shared_ptr<GeomAPI_Pnt> aCenter(aSketch->to3D(aCenterAttr->x(), aCenterAttr->y()));
-      // make a visible point
-      boost::shared_ptr<GeomAPI_Shape> aCenterPointShape = GeomAlgoAPI_PointBuilder::point(aCenter);
-      aShapes.push_back(aCenterPointShape);
-
-      // make a visible circle
-      boost::shared_ptr<GeomDataAPI_Dir> aNDir = 
-        boost::dynamic_pointer_cast<GeomDataAPI_Dir>(aSketch->data()->attribute(SKETCH_ATTR_NORM));
-      bool aHasPlane = aNDir && !(aNDir->x() == 0 && aNDir->y() == 0 && aNDir->z() == 0);
-      if (aHasPlane) {
-        boost::shared_ptr<GeomAPI_Dir> aNormal = aNDir->dir();
-        boost::shared_ptr<GeomAPI_Pnt> aStartPoint(aSketch->to3D(aStartAttr->x(), aStartAttr->y()));
-
-        // compute and change the arc end point
-        boost::shared_ptr<GeomDataAPI_Point2D> anEndAttr = 
-          boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(data()->attribute(ARC_ATTR_END));
-        if (anEndAttr->isInitialized())
-        {
-          boost::shared_ptr<GeomAPI_Circ2d> aCircleForArc(
-            new GeomAPI_Circ2d(aCenterAttr->pnt(), aStartAttr->pnt()));
-          boost::shared_ptr<GeomAPI_Pnt2d> aProjection = aCircleForArc->project(anEndAttr->pnt());
-          if (aProjection && anEndAttr->pnt()->distance(aProjection) > tolerance)
-            anEndAttr->setValue(aProjection);
-        }
-        boost::shared_ptr<GeomAPI_Pnt> aEndPoint(aSketch->to3D(anEndAttr->x(), anEndAttr->y()));
+    std::shared_ptr<GeomDataAPI_Point2D> aCenterAttr = std::dynamic_pointer_cast<
+        GeomDataAPI_Point2D>(data()->attribute(CENTER_ID()));
+    // compute the arc start point
+    std::shared_ptr<GeomDataAPI_Point2D> aStartAttr = std::dynamic_pointer_cast<
+        GeomDataAPI_Point2D>(data()->attribute(START_ID()));
+
+    std::shared_ptr<GeomAPI_Pnt> aCenter(aSketch->to3D(aCenterAttr->x(), aCenterAttr->y()));
+    // make a visible point
+    std::shared_ptr<GeomAPI_Shape> aCenterPointShape = GeomAlgoAPI_PointBuilder::point(aCenter);
+    std::shared_ptr<ModelAPI_ResultConstruction> aConstr1 = document()->createConstruction(
+        data(), 0);
+    aConstr1->setShape(aCenterPointShape);
+    aConstr1->setIsInHistory(false);
+    setResult(aConstr1, 0);
+
+    // make a visible circle
+    std::shared_ptr<GeomDataAPI_Dir> aNDir = std::dynamic_pointer_cast<GeomDataAPI_Dir>(
+        aSketch->data()->attribute(SketchPlugin_Sketch::NORM_ID()));
+    std::shared_ptr<GeomAPI_Dir> aNormal = aNDir->dir();
+    std::shared_ptr<GeomAPI_Pnt> aStartPoint(aSketch->to3D(aStartAttr->x(), aStartAttr->y()));
 
-        boost::shared_ptr<GeomAPI_Shape> aCircleShape = 
-                   GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, aStartPoint, aEndPoint, aNormal);
-        if (aCircleShape)
-          aShapes.push_back(aCircleShape);
+    // compute and change the arc end point
+    std::shared_ptr<GeomDataAPI_Point2D> anEndAttr = std::dynamic_pointer_cast<
+        GeomDataAPI_Point2D>(data()->attribute(END_ID()));
+    std::shared_ptr<GeomAPI_Circ2d> aCircleForArc(
+        new GeomAPI_Circ2d(aCenterAttr->pnt(), aStartAttr->pnt()));
+    std::shared_ptr<GeomAPI_Pnt2d> aProjection = aCircleForArc->project(anEndAttr->pnt());
+    if (aProjection && anEndAttr->pnt()->distance(aProjection) > tolerance)
+      anEndAttr->setValue(aProjection);
+    std::shared_ptr<GeomAPI_Pnt> aEndPoint(aSketch->to3D(anEndAttr->x(), anEndAttr->y()));
+    AttributeBooleanPtr isInversed =
+        std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(attribute(INVERSED_ID()));
+
+    std::shared_ptr<GeomAPI_Dir> anXDir(new GeomAPI_Dir(aStartPoint->xyz()->decreased(aCenter->xyz())));
+    std::shared_ptr<GeomAPI_Ax2> anAx2(new GeomAPI_Ax2(aCenter, aNormal, anXDir));
+    std::shared_ptr<GeomAPI_Circ> aCirc(new GeomAPI_Circ(anAx2, aCenter->distance(aStartPoint)));
+    double aParameterNew = 0.0;
+    if(aCirc->parameter(aEndPoint, paramTolerance, aParameterNew)) {
+      if(0 <= myParamBefore && myParamBefore <= PI / 2.0
+        && PI * 1.5 <= aParameterNew && aParameterNew <= PI * 2.0) {
+          isInversed->setValue(true);
+      } else if(PI * 1.5 <= myParamBefore && myParamBefore <= PI * 2.0
+        && 0 <= aParameterNew && aParameterNew <= PI / 2.0) {
+          isInversed->setValue(false);
       }
-      boost::shared_ptr<GeomAPI_Shape> aCompound = GeomAlgoAPI_CompoundBuilder::compound(aShapes);
-      setPreview(aCompound);
     }
+    myParamBefore = aParameterNew;
+
+    std::shared_ptr<GeomAPI_Shape> aCircleShape;
+    if(!isInversed->value()) {
+      aCircleShape = GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, aStartPoint, aEndPoint, aNormal);
+    } else {
+      aCircleShape = GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, aEndPoint, aStartPoint, aNormal);
+    }
+
+    if (aCircleShape) {
+      std::shared_ptr<ModelAPI_ResultConstruction> aConstr2 = document()->createConstruction(
+          data(), 1);
+      aConstr2->setShape(aCircleShape);
+      aConstr2->setIsInHistory(false);
+      setResult(aConstr2, 1);
+    }
+
+    AttributeRefAttrPtr aTangentPoint = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        attribute(TANGENT_POINT_ID()));
+    if (!hasResult && aTangentPoint->attr())
+      tangencyArcConstraints();
   }
-  return getPreview();
 }
 
-boost::shared_ptr<GeomAPI_AISObject> SketchPlugin_Arc::getAISObject(
-                                boost::shared_ptr<GeomAPI_AISObject> thePrevious)
+AISObjectPtr SketchPlugin_Arc::getAISObject(AISObjectPtr thePrevious)
 {
-  return prepareAISShape(thePrevious);
+  SketchPlugin_Sketch* aSketch = sketch();
+  if (aSketch) {
+    // if the feature is valid, the execute() method should be performed, AIS object is empty
+    if (!isFeatureValid()) {
+      // compute a circle point in 3D view
+      std::shared_ptr<GeomDataAPI_Point2D> aCenterAttr = std::dynamic_pointer_cast<
+          GeomDataAPI_Point2D>(data()->attribute(CENTER_ID()));
+      if (aCenterAttr->isInitialized()) {
+        std::shared_ptr<GeomAPI_Pnt> aCenter(aSketch->to3D(aCenterAttr->x(), aCenterAttr->y()));
+
+        std::shared_ptr<GeomDataAPI_Point2D> aStartAttr = std::dynamic_pointer_cast<
+            GeomDataAPI_Point2D>(data()->attribute(SketchPlugin_Arc::START_ID()));
+        std::shared_ptr<GeomDataAPI_Point2D> aEndAttr = std::dynamic_pointer_cast<
+            GeomDataAPI_Point2D>(data()->attribute(SketchPlugin_Arc::END_ID()));
+        AttributeStringPtr aTypeAttr = std::dynamic_pointer_cast<ModelAPI_AttributeString>(
+            data()->attribute(ARC_TYPE()));
+
+        if (aStartAttr->isInitialized()) {
+          // make a visible circle
+          std::shared_ptr<GeomDataAPI_Dir> aNDir = std::dynamic_pointer_cast<GeomDataAPI_Dir>(
+              aSketch->data()->attribute(SketchPlugin_Sketch::NORM_ID()));
+          bool aHasPlane = aNDir && !(aNDir->x() == 0 && aNDir->y() == 0 && aNDir->z() == 0);
+          if (aHasPlane) {
+            std::shared_ptr<GeomAPI_Dir> aNormal = aNDir->dir();
+            std::shared_ptr<GeomAPI_Pnt> aStartPoint(aSketch->to3D(aStartAttr->x(), aStartAttr->y()));
+            std::shared_ptr<GeomAPI_Pnt> aEndPoint = aStartPoint;
+            if (aTypeAttr && aTypeAttr->isInitialized() &&
+                aTypeAttr->value() == ARC_TYPE_THREE_POINTS() && aEndAttr->isInitialized())
+              aEndPoint = aSketch->to3D(aEndAttr->x(), aEndAttr->y());
+            std::shared_ptr<GeomAPI_Shape> aCircleShape = GeomAlgoAPI_EdgeBuilder::lineCircleArc(
+                                                            aCenter, aStartPoint, aEndPoint, aNormal);
+            if (aCircleShape) {
+              std::list<std::shared_ptr<GeomAPI_Shape> > aShapes;
+              // make a visible point
+              std::shared_ptr<GeomAPI_Shape> aCenterPointShape = GeomAlgoAPI_PointBuilder::point(aCenter);
+              aShapes.push_back(aCenterPointShape);
+
+              aShapes.push_back(aCircleShape);
+              if (!aShapes.empty())
+              {
+                std::shared_ptr<GeomAPI_Shape> aCompound = GeomAlgoAPI_CompoundBuilder::compound(aShapes);
+                AISObjectPtr anAIS = thePrevious;
+                if (!anAIS)
+                  anAIS = AISObjectPtr(new GeomAPI_AISObject);
+                anAIS->createShape(aCompound);
+                anAIS->setWidth(3);
+                return anAIS;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+  return AISObjectPtr();
 }
 
 void SketchPlugin_Arc::move(double theDeltaX, double theDeltaY)
 {
-  boost::shared_ptr<ModelAPI_Data> aData = data();
+  std::shared_ptr<ModelAPI_Data> aData = data();
   if (!aData->isValid())
     return;
 
-  boost::shared_ptr<GeomDataAPI_Point2D> aPoint1 =
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(ARC_ATTR_CENTER));
-  aPoint1->setValue(aPoint1->x() + theDeltaX, aPoint1->y() + theDeltaY);
+  aData->blockSendAttributeUpdated(true);
+
+  myStartUpdate = true;
+  myEndUpdate = true;
+  std::shared_ptr<GeomDataAPI_Point2D> aPoint2 = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(
+      aData->attribute(SketchPlugin_Arc::START_ID()));
+  aPoint2->move(theDeltaX, theDeltaY);
+
+  std::shared_ptr<GeomDataAPI_Point2D> aPoint3 = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(
+      aData->attribute(SketchPlugin_Arc::END_ID()));
+  aPoint3->move(theDeltaX, theDeltaY);
+  myStartUpdate = false;
+  myEndUpdate = false;
+
+  std::shared_ptr<GeomDataAPI_Point2D> aPoint1 = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(
+      aData->attribute(SketchPlugin_Arc::CENTER_ID()));
+  aPoint1->move(theDeltaX, theDeltaY);
+
+  std::shared_ptr<GeomDataAPI_Point2D> aPassedPoint =
+      std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(PASSED_POINT_ID()));
+  aPassedPoint->move(theDeltaX, theDeltaY);
+  aData->blockSendAttributeUpdated(false);
+}
+
+bool SketchPlugin_Arc::isFixed() {
+  return data()->selection(EXTERNAL_ID())->context().get() != NULL;
+}
+
+bool SketchPlugin_Arc::isFeatureValid()
+{
+  AttributeStringPtr anArcTypeAttr =
+      std::dynamic_pointer_cast<ModelAPI_AttributeString>(data()->attribute(ARC_TYPE()));
+  if (!anArcTypeAttr)
+    return false;
+  std::string anArcType = anArcTypeAttr->value();
+
+  std::shared_ptr<GeomDataAPI_Point2D> aCenterAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(SketchPlugin_Arc::CENTER_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> aStartAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(SketchPlugin_Arc::START_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> anEndAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(SketchPlugin_Arc::END_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> aPassedAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(PASSED_POINT_ID()));
+
+  bool isValid = false;
+  if (anArcType == ARC_TYPE_THREE_POINTS())
+    isValid = aStartAttr->isInitialized() && anEndAttr->isInitialized() && aPassedAttr->isInitialized();
+  else
+    isValid = aCenterAttr->isInitialized() && aStartAttr->isInitialized() && anEndAttr->isInitialized();
+
+  return isValid;
+}
+
+static inline void adjustPeriod(double& theParam)
+{
+  static const double PERIOD = 2.0 * PI;
+  while (theParam < 0.0) theParam += PERIOD;
+  while (theParam >= PERIOD) theParam -= PERIOD;
+}
+
+static inline void calculateArcAngleRadius(
+    const std::shared_ptr<GeomAPI_Circ2d>& theCircle,
+    const std::shared_ptr<GeomAPI_Pnt2d>& theStartPoint,
+    const std::shared_ptr<GeomAPI_Pnt2d>& theEndPoint,
+    const std::shared_ptr<GeomAPI_Pnt2d>& thePassedPoint,
+    AttributeDoublePtr theAngleAttr,
+    AttributeDoublePtr theRadiusAttr)
+{
+  double aStartParam, aEndParam, aPassedParam;
+  theCircle->parameter(theStartPoint, paramTolerance, aStartParam);
+  theCircle->parameter(theEndPoint, paramTolerance, aEndParam);
+  theCircle->parameter(thePassedPoint, paramTolerance, aPassedParam);
+  adjustPeriod(aStartParam);
+  adjustPeriod(aEndParam);
+  adjustPeriod(aPassedParam);
+
+  if (aPassedParam >= aStartParam && aPassedParam <= aEndParam)
+    theAngleAttr->setValue((aEndParam - aStartParam) * 180.0 / PI);
+  else
+    theAngleAttr->setValue((aEndParam - aStartParam - 2.0 * PI) * 180.0 / PI);
+  theRadiusAttr->setValue(theCircle->radius());
+}
+
+static inline void calculatePassedPoint(
+    const std::shared_ptr<GeomAPI_Pnt2d>& theCenter,
+    const std::shared_ptr<GeomAPI_Pnt2d>& theStartPoint,
+    const std::shared_ptr<GeomAPI_Pnt2d>& theEndPoint,
+    bool theArcReversed,
+    std::shared_ptr<GeomDataAPI_Point2D> thePassedPoint)
+{
+  std::shared_ptr<GeomAPI_Dir2d> aStartDir(new GeomAPI_Dir2d(
+      theStartPoint->xy()->decreased(theCenter->xy())));
+  std::shared_ptr<GeomAPI_Dir2d> aEndDir(new GeomAPI_Dir2d(
+      theEndPoint->xy()->decreased(theCenter->xy())));
+  std::shared_ptr<GeomAPI_XY> aMidDirXY = aStartDir->xy()->added(aEndDir->xy());
+  if (aMidDirXY->dot(aMidDirXY) < tolerance * tolerance) {
+    // start and end directions are opposite, so middle direction will be orthogonal
+    aMidDirXY->setX(-aStartDir->y());
+    aMidDirXY->setY(aStartDir->x());
+  }
+  std::shared_ptr<GeomAPI_Dir2d> aMidDir(new GeomAPI_Dir2d(aMidDirXY));
+  if ((aStartDir->cross(aMidDir) > 0) ^ !theArcReversed)
+    aMidDir->reverse();
+
+  double aRadius = theCenter->distance(theStartPoint);
+  std::shared_ptr<GeomAPI_XY> aPassedPnt = theCenter->xy()->added( aMidDir->xy()->multiplied(aRadius) );
+  thePassedPoint->setValue(aPassedPnt->x(), aPassedPnt->y());
+}
+
+void SketchPlugin_Arc::updateDependentAttributes()
+{
+  std::shared_ptr<GeomDataAPI_Point2D> aCenterAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(CENTER_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> aStartAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(START_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> anEndAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(END_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> aPassedPoint =
+      std::dynamic_pointer_cast<GeomDataAPI_Point2D>(attribute(PASSED_POINT_ID()));
+  AttributeDoublePtr aRadiusAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
+      data()->attribute(RADIUS_ID()));
+  AttributeDoublePtr anAngleAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
+      data()->attribute(ANGLE_ID()));
+
+  if (!aPassedPoint)
+    return;
+
+  data()->blockSendAttributeUpdated(true);
+
+  calculatePassedPoint(aCenterAttr->pnt(), aStartAttr->pnt(), anEndAttr->pnt(),
+                       isReversed(), aPassedPoint);
+  if (aRadiusAttr && anAngleAttr) {
+    std::shared_ptr<GeomAPI_Circ2d> aCircle(
+        new GeomAPI_Circ2d(aStartAttr->pnt(), anEndAttr->pnt(), aPassedPoint->pnt()));
+    calculateArcAngleRadius(aCircle, aStartAttr->pnt(), anEndAttr->pnt(), aPassedPoint->pnt(),
+                            anAngleAttr, aRadiusAttr);
+  }
+  data()->blockSendAttributeUpdated(false);
+}
+
+
+void SketchPlugin_Arc::attributeChanged(const std::string& theID)
+{
+  std::shared_ptr<GeomDataAPI_Point2D> aCenterAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(CENTER_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> aStartAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(START_ID()));
+  std::shared_ptr<GeomDataAPI_Point2D> anEndAttr = std::dynamic_pointer_cast<
+      GeomDataAPI_Point2D>(data()->attribute(END_ID()));
+  // the second condition for unability to move external segments anywhere
+  if (theID == EXTERNAL_ID() || isFixed()) {
+    std::shared_ptr<GeomAPI_Shape> aSelection = data()->selection(EXTERNAL_ID())->value();
+    // update arguments due to the selection value
+    if (aSelection && !aSelection->isNull() && aSelection->isEdge()) {
+      std::shared_ptr<GeomAPI_Edge> anEdge( new GeomAPI_Edge(aSelection));
+      std::shared_ptr<GeomAPI_Circ> aCirc = anEdge->circle();
+      if (aCirc.get()) {
+        aStartAttr->setValue(sketch()->to2D(anEdge->firstPoint()));
+        anEndAttr->setValue(sketch()->to2D(anEdge->lastPoint()));
+        aCenterAttr->setValue(sketch()->to2D(aCirc->center()));
+      }
+    }
+    return;
+  }
+
+  AttributeDoublePtr aRadiusAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
+      data()->attribute(RADIUS_ID()));
+  AttributeDoublePtr anAngleAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
+      data()->attribute(ANGLE_ID()));
+
+  if (theID == RADIUS_ID()) {
+    if (!aStartAttr->isInitialized() || !anEndAttr->isInitialized())
+      return;
+    // move center and passed point
+    std::shared_ptr<GeomAPI_Pnt2d> aStartPnt = aStartAttr->pnt();
+    std::shared_ptr<GeomAPI_Pnt2d> aEndPnt = anEndAttr->pnt();
+    double aDist = aStartPnt->distance(aEndPnt);
+    if (fabs(aDist) < tolerance)
+      return;
+    std::shared_ptr<GeomAPI_XY> aDir = aEndPnt->xy()->decreased(aStartPnt->xy());
+    std::shared_ptr<GeomAPI_Dir2d> aMidPerpDir(new GeomAPI_Dir2d(-aDir->y(), aDir->x()));
+    std::shared_ptr<GeomAPI_XY> aMidPnt = aStartPnt->xy()->added(aEndPnt->xy())->multiplied(0.5);
+
+    double anAngle = anAngleAttr->value() * PI / 180.0;
+    adjustPeriod(anAngle);
+    if (anAngle > PI)
+      aMidPerpDir->reverse();
+
+    double aRadius = aRadiusAttr->value();
+    aDist = sqrt(aRadius * aRadius - aDist * aDist / 4.0);
+
+    std::shared_ptr<GeomAPI_XY> aCenter = aMidPnt->added(aMidPerpDir->xy()->multiplied(aDist));
+
+    data()->blockSendAttributeUpdated(true);
+    aCenterAttr->setValue(aCenter->x(), aCenter->y());
+    updateDependentAttributes();
+    data()->blockSendAttributeUpdated(false);
+    return;
+  }
+  if (theID == ANGLE_ID()) {
+    if (!aStartAttr->isInitialized() || !aCenterAttr->isInitialized())
+      return;
+    data()->blockSendAttributeUpdated(true);
+    // move end point and passed point
+    std::shared_ptr<GeomAPI_XY> aCenter = aCenterAttr->pnt()->xy();
+    double anAngle = anAngleAttr->value() * PI / 180.0;
+    double sinA = sin(anAngle);
+    double cosA = cos(anAngle);
+    std::shared_ptr<GeomAPI_XY> aStartDir = aStartAttr->pnt()->xy()->decreased(aCenter);
+    std::shared_ptr<GeomAPI_XY> aDir(new GeomAPI_XY(
+        aStartDir->x() * cosA - aStartDir->y() * sinA,
+        aStartDir->x() * sinA + aStartDir->y() * cosA));
+    anEndAttr->setValue(aCenter->x() + aDir->x(), aCenter->y() + aDir->y());
+
+    anAngle /= 2.0;
+    sinA = sin(anAngle);
+    cosA = cos(anAngle);
+    aDir = std::shared_ptr<GeomAPI_XY>(new GeomAPI_XY(
+        aStartDir->x() * cosA - aStartDir->y() * sinA,
+        aStartDir->x() * sinA + aStartDir->y() * cosA));
+    std::shared_ptr<GeomDataAPI_Point2D> aPassedPoint =
+        std::dynamic_pointer_cast<GeomDataAPI_Point2D>(attribute(PASSED_POINT_ID()));
+    aPassedPoint->setValue(aCenter->x() + aDir->x(), aCenter->y() + aDir->y());
+
+    std::shared_ptr<GeomAPI_Circ2d> aCircle(
+        new GeomAPI_Circ2d(aStartAttr->pnt(), anEndAttr->pnt(), aPassedPoint->pnt()));
+    calculateArcAngleRadius(aCircle, aStartAttr->pnt(), anEndAttr->pnt(), aPassedPoint->pnt(),
+                            anAngleAttr, aRadiusAttr);
+    data()->blockSendAttributeUpdated(false);
+    return;
+  }
+
+  if (theID == CENTER_ID()) {
+    if (!isFeatureValid())
+      return;
+    if (aCenterAttr->pnt()->distance(aStartAttr->pnt()) < tolerance)
+      return;
+    data()->blockSendAttributeUpdated(true);
+    // compute and change the arc end point
+    std::shared_ptr<GeomAPI_Circ2d> aCircleForArc(
+        new GeomAPI_Circ2d(aCenterAttr->pnt(), aStartAttr->pnt()));
+    std::shared_ptr<GeomAPI_Pnt2d> aProjection = aCircleForArc->project(anEndAttr->pnt());
+    if (aProjection && anEndAttr->pnt()->distance(aProjection) > tolerance)
+      anEndAttr->setValue(aProjection);
+    updateDependentAttributes();
+    data()->blockSendAttributeUpdated(false);
+    return;
+  }
+
+  AttributeStringPtr aTypeAttr =
+      std::dynamic_pointer_cast<ModelAPI_AttributeString>(attribute(ARC_TYPE()));
+  if (!aTypeAttr)
+    return;
+  std::string anArcType = aTypeAttr->value();
+
+  // update the points in accordance to the changed point changes
+  if (anArcType == ARC_TYPE_CENTER_START_END()) {
+    if (!isFeatureValid())
+      return;
+    updateDependentAttributes();
+  }
+  else if (anArcType == ARC_TYPE_THREE_POINTS() &&
+          (theID == START_ID() || theID == END_ID() || theID == PASSED_POINT_ID())) {
+    data()->blockSendAttributeUpdated(true);
+
+    std::shared_ptr<GeomAPI_Pnt2d> aPoints[3];
+    int aNbInitialized = 0;
+    for (int i = 1; i <= 3; ++i) {
+      std::shared_ptr<GeomDataAPI_Point2D> aCurPnt =
+          std::dynamic_pointer_cast<GeomDataAPI_Point2D>(attribute(POINT_ID(i)));
+      if (aCurPnt->isInitialized())
+        aPoints[aNbInitialized++] = aCurPnt->pnt();
+    }
+
+    if (aNbInitialized == 1)
+      aCenterAttr->setValue(aPoints[0]->x(), aPoints[0]->y());
+    else if (aNbInitialized == 2) {
+      // calculate center point, which gives a quarter of circle for the given start and end points
+      std::shared_ptr<GeomAPI_Pnt2d> aStartPnt = aPoints[0];
+      std::shared_ptr<GeomAPI_Pnt2d> aEndPnt = aPoints[1];
+      std::shared_ptr<GeomAPI_XY> aDir = aEndPnt->xy()->decreased(aStartPnt->xy())->multiplied(0.5);
+      double x = aDir->x();
+      double y = aDir->y();
+      aDir->setX(x - y);
+      aDir->setY(y + x);
+      std::shared_ptr<GeomAPI_XY> aCenter = aStartPnt->xy()->added(aDir);
+      double aRadius = sqrt(aDir->dot(aDir));
+
+      aCenterAttr->setValue(aCenter->x(), aCenter->y());
+      aRadiusAttr->setValue(aRadius);
+      anAngleAttr->setValue(90.0);
+    }
+    else {
+      std::shared_ptr<GeomAPI_Circ2d> aCircle(
+          new GeomAPI_Circ2d(aPoints[0], aPoints[1], aPoints[2]));
+
+      std::shared_ptr<GeomAPI_Pnt2d> aCenter = aCircle->center();
+      if (aCenter) {
+        aCenterAttr->setValue(aCenter);
+        if (theID == START_ID() || theID == END_ID())
+          updateDependentAttributes();
+        else
+          calculateArcAngleRadius(aCircle, aPoints[0], aPoints[1], aPoints[2],
+                                  anAngleAttr, aRadiusAttr);
+      }
+    }
+
+    data()->blockSendAttributeUpdated(false);
+  }
+  else if (anArcType == ARC_TYPE_TANGENT() && (theID == TANGENT_POINT_ID() || theID == END_ID())) {
+    SketchPlugin_Sketch* aSketch = sketch();
+    AttributeRefAttrPtr aTangPtAttr = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        data()->attribute(TANGENT_POINT_ID()));
+
+    if (aTangPtAttr->isInitialized() && anEndAttr->isInitialized()) {
+      data()->blockSendAttributeUpdated(true);
+      // compute orthogonal direction
+      std::shared_ptr<GeomAPI_Dir2d> anOrthoDir;
+      std::shared_ptr<GeomDataAPI_Point2D> aTangentPoint =
+          std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aTangPtAttr->attr());
+      std::shared_ptr<GeomAPI_Pnt2d> aTangPnt2d = aTangentPoint->pnt();
+      FeaturePtr aTangFeature = ModelAPI_Feature::feature(aTangentPoint->owner());
+      std::shared_ptr<GeomAPI_Edge> aTangEdge = std::dynamic_pointer_cast<GeomAPI_Edge>(
+          aTangFeature->lastResult()->shape());
+      if (aTangEdge->isLine()) {
+        std::shared_ptr<GeomAPI_Dir> aDir = aTangEdge->line()->direction();
+        std::shared_ptr<GeomAPI_Pnt> aPnt(new GeomAPI_Pnt(aDir->x(), aDir->y(), aDir->z()));
+        std::shared_ptr<GeomAPI_Pnt2d> aPnt2d = aSketch->to2D(aPnt);
+        anOrthoDir = std::shared_ptr<GeomAPI_Dir2d>(new GeomAPI_Dir2d(-aPnt2d->y(), aPnt2d->x()));
+      }
+      else if (aTangEdge->isArc()) {
+        std::shared_ptr<GeomAPI_Pnt> aCenter = aTangEdge->circle()->center();
+        std::shared_ptr<GeomAPI_Pnt2d> aCenter2d = aSketch->to2D(aCenter);
+        anOrthoDir = std::shared_ptr<GeomAPI_Dir2d>(
+            new GeomAPI_Dir2d(aTangPnt2d->xy()->decreased(aCenter2d->xy())));
+      }
+
+      // compute parameters of the middle perpendicular
+      std::shared_ptr<GeomAPI_XY> aEndPntCoord = anEndAttr->pnt()->xy();
+      std::shared_ptr<GeomAPI_XY> aTempDir = aEndPntCoord->decreased(aTangPnt2d->xy());
+      std::shared_ptr<GeomAPI_Dir2d> aMidDir(new GeomAPI_Dir2d(-aTempDir->y(), aTempDir->x()));
+      std::shared_ptr<GeomAPI_Pnt2d> aMidPnt(
+          new GeomAPI_Pnt2d(aEndPntCoord->added(aTangPnt2d->xy())->multiplied(0.5)));
+
+      // compute center of arc by calculating intersection of orthogonal line and middle perpendicular
+      std::shared_ptr<GeomAPI_Lin2d> anOrthoLine(new GeomAPI_Lin2d(aTangPnt2d, anOrthoDir));
+      std::shared_ptr<GeomAPI_Lin2d> aMiddleLine(new GeomAPI_Lin2d(aMidPnt, aMidDir));
+      std::shared_ptr<GeomAPI_Pnt2d> aCenter = anOrthoLine->intersect(aMiddleLine);
+      if (aCenter) {
+        aCenterAttr->setValue(aCenter);
+        aStartAttr->setValue(aTangPnt2d);
+        updateDependentAttributes();
+      }
 
-  boost::shared_ptr<GeomDataAPI_Point2D> aPoint2 =
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(ARC_ATTR_START));
-  aPoint2->setValue(aPoint2->x() + theDeltaX, aPoint2->y() + theDeltaY);
+      data()->blockSendAttributeUpdated(false);
 
-  boost::shared_ptr<GeomDataAPI_Point2D> aPoint3 =
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(ARC_ATTR_END));
-  aPoint3->setValue(aPoint3->x() + theDeltaX, aPoint3->y() + theDeltaY);
+      if (theID == TANGENT_POINT_ID())
+        tangencyArcConstraints();
+    }
+  }
+}
+
+void SketchPlugin_Arc::setReversed(bool isReversed)
+{
+  std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(attribute(INVERSED_ID()))->setValue(isReversed);
+  myParamBefore = 0.0;
 }
 
-double SketchPlugin_Arc::distanceToPoint(const boost::shared_ptr<GeomAPI_Pnt2d>& thePoint)
+bool SketchPlugin_Arc::isReversed()
 {
-  double aDelta = 0;
-  boost::shared_ptr<ModelAPI_Data> aData = data();
-
-  boost::shared_ptr<GeomDataAPI_Point2D> aPoint1 =
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(ARC_ATTR_CENTER));
-  aDelta = aPoint1->pnt()->distance(thePoint);
-
-  boost::shared_ptr<GeomDataAPI_Point2D> aPoint2 =
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(ARC_ATTR_START));
-  double aDistance = aPoint2->pnt()->distance(thePoint);
-  if (aDelta < aDistance)
-    aDelta = aDistance;
-
-  boost::shared_ptr<GeomDataAPI_Point2D> aPoint3 =
-        boost::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(ARC_ATTR_END));
-  aDistance = aPoint3->pnt()->distance(thePoint);
-  if (aDelta < aDistance)
-    aDelta = aDistance;
-
-  return aDelta;
+  return std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(attribute(INVERSED_ID()))->value();
+}
+
+void SketchPlugin_Arc::tangencyArcConstraints()
+{
+  if (!lastResult())
+    return;
+
+  std::shared_ptr<GeomDataAPI_Point2D> aStartAttr =
+      std::dynamic_pointer_cast<GeomDataAPI_Point2D>(attribute(START_ID()));
+  AttributeRefAttrPtr aTangPtAttr = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+      attribute(TANGENT_POINT_ID()));
+  if (!aTangPtAttr->attr())
+    return;
+
+  FeaturePtr aFeature = ModelAPI_Feature::feature(aStartAttr->owner());
+  ObjectPtr aThisArc = aFeature->lastResult();
+  aFeature = ModelAPI_Feature::feature(aTangPtAttr->attr()->owner());
+  ObjectPtr aTangFeature = aFeature->lastResult();
+
+  // trying to find constraints to fix the tangency of the arc
+  std::set<FeaturePtr> aCoincidence;
+  std::set<FeaturePtr> aTangency;
+
+  AttributeRefAttrPtr aRefAttrA, aRefAttrB;
+  std::set<AttributePtr> aRefs = data()->refsToMe();
+  const std::set<AttributePtr>& aRefsToResult = lastResult()->data()->refsToMe();
+  aRefs.insert(aRefsToResult.begin(), aRefsToResult.end());
+  std::set<AttributePtr>::const_iterator aRefIt = aRefs.begin();
+  for (; aRefIt != aRefs.end(); ++aRefIt) {
+    FeaturePtr aConstrFeature = ModelAPI_Feature::feature((*aRefIt)->owner());
+    if (aConstrFeature->getKind() == SketchPlugin_ConstraintCoincidence::ID()) {
+      aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          aConstrFeature->attribute(SketchPlugin_Constraint::ENTITY_A()));
+      aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          aConstrFeature->attribute(SketchPlugin_Constraint::ENTITY_B()));
+      if ((aRefAttrA && aRefAttrA->attr() == aStartAttr) ||
+          (aRefAttrB && aRefAttrB->attr() == aStartAttr))
+        aCoincidence.insert(aConstrFeature);
+    }
+    else if (aConstrFeature->getKind() == SketchPlugin_ConstraintTangent::ID()) {
+      aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          aConstrFeature->attribute(SketchPlugin_Constraint::ENTITY_A()));
+      aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          aConstrFeature->attribute(SketchPlugin_Constraint::ENTITY_B()));
+      if ((aRefAttrA && aRefAttrA->object() == aThisArc) ||
+          (aRefAttrB && aRefAttrB->object() == aThisArc))
+        aTangency.insert(aConstrFeature);
+    }
+  }
+  // search applicable pair of constraints
+  bool isFound = false;
+  FeaturePtr aPrevCoincidence, aPrevTangency;
+  std::set<FeaturePtr>::const_iterator aCIt, aTIt;
+  for (aCIt = aCoincidence.begin(); aCIt != aCoincidence.end() && !isFound; ++aCIt) {
+    aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        (*aCIt)->attribute(SketchPlugin_Constraint::ENTITY_A()));
+    aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        (*aCIt)->attribute(SketchPlugin_Constraint::ENTITY_B()));
+    AttributePtr anOtherPoint =
+        aRefAttrA->attr() == aStartAttr ? aRefAttrB->attr() : aRefAttrA->attr();
+    for (aTIt = aTangency.begin(); aTIt != aTangency.end() && !isFound; ++aTIt) {
+      aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          (*aTIt)->attribute(SketchPlugin_Constraint::ENTITY_A()));
+      aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          (*aTIt)->attribute(SketchPlugin_Constraint::ENTITY_B()));
+      ObjectPtr anOtherObject = aRefAttrA->object() == aThisArc ?
+          aRefAttrB->object() : aRefAttrA->object();
+      if (anOtherPoint->owner() == anOtherObject) {
+        isFound = true;
+        aPrevCoincidence = *aCIt;
+        aPrevTangency = *aTIt;
+      }
+    }
+  }
+
+  if (isFound) {
+    // update previous constraints
+    aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aPrevCoincidence->attribute(SketchPlugin_Constraint::ENTITY_A()));
+    aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aPrevCoincidence->attribute(SketchPlugin_Constraint::ENTITY_B()));
+    if (aRefAttrA->attr() == aStartAttr)
+      aRefAttrB->setAttr(aTangPtAttr->attr());
+    else
+      aRefAttrA->setAttr(aTangPtAttr->attr());
+
+    aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aPrevTangency->attribute(SketchPlugin_Constraint::ENTITY_A()));
+    aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aPrevTangency->attribute(SketchPlugin_Constraint::ENTITY_B()));
+    if (aRefAttrA->object() == aThisArc)
+      aRefAttrB->setObject(aTangFeature);
+    else
+      aRefAttrA->setObject(aTangFeature);
+  } else {
+    // Wait all constraints being removed, then send update events
+    static Events_ID aDeleteEvent = Events_Loop::eventByName(EVENT_OBJECT_DELETED);
+    bool isDeleteFlushed = Events_Loop::loop()->isFlushed(aDeleteEvent);
+    if (isDeleteFlushed)
+      Events_Loop::loop()->setFlushed(aDeleteEvent, false);
+    // Remove all obtained constraints which use current arc, because
+    // there is no information which of them were used to build tangency arc.
+    DocumentPtr aDoc = sketch()->document();
+    for (aCIt = aCoincidence.begin(); aCIt != aCoincidence.end(); ++aCIt)
+      aDoc->removeFeature(*aCIt);
+    for (aTIt = aTangency.begin(); aTIt != aTangency.end(); ++aTIt)
+      aDoc->removeFeature(*aTIt);
+    // Send events to update the sub-features by the solver.
+    if (isDeleteFlushed)
+      Events_Loop::loop()->setFlushed(aDeleteEvent, true);
+    else
+      Events_Loop::loop()->flush(aDeleteEvent);
+
+    // Wait all constraints being created, then send update events
+    static Events_ID anUpdateEvent = Events_Loop::eventByName(EVENT_OBJECT_UPDATED);
+    bool isUpdateFlushed = Events_Loop::loop()->isFlushed(anUpdateEvent);
+    if (isUpdateFlushed)
+      Events_Loop::loop()->setFlushed(anUpdateEvent, false);
+
+    // Create new constraints
+    FeaturePtr aConstraint = sketch()->addFeature(SketchPlugin_ConstraintCoincidence::ID());
+    aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aConstraint->attribute(SketchPlugin_Constraint::ENTITY_A()));
+    aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aConstraint->attribute(SketchPlugin_Constraint::ENTITY_B()));
+    aRefAttrA->setAttr(aStartAttr);
+    aRefAttrB->setAttr(aTangPtAttr->attr());
+    aConstraint->execute();
+    ModelAPI_EventCreator::get()->sendUpdated(aConstraint, anUpdateEvent);
+
+    aConstraint = sketch()->addFeature(SketchPlugin_ConstraintTangent::ID());
+    aRefAttrA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aConstraint->attribute(SketchPlugin_Constraint::ENTITY_A()));
+    aRefAttrB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+        aConstraint->attribute(SketchPlugin_Constraint::ENTITY_B()));
+    aRefAttrA->setObject(aThisArc);
+    aRefAttrB->setObject(aTangFeature);
+    aConstraint->execute();
+    ModelAPI_EventCreator::get()->sendUpdated(aConstraint, anUpdateEvent);
+
+    // Send events to update the sub-features by the solver.
+    if(isUpdateFlushed)
+      Events_Loop::loop()->setFlushed(anUpdateEvent, true);
+  }
 }