X-Git-Url: http://git.salome-platform.org/gitweb/?a=blobdiff_plain;f=src%2FSketchPlugin%2FSketchPlugin_Arc.cpp;h=c72230a16b5d0c438065061bbc6a2025a27121f7;hb=fc72d43b677baa05ae7fd317346fd8b723b799ed;hp=be7ad7dc72845ce56f0df6a86574181a88e2c311;hpb=5b6031b015602aa07f5a6fc668c13ac3faf7a8a9;p=modules%2Fshaper.git

diff --git a/src/SketchPlugin/SketchPlugin_Arc.cpp b/src/SketchPlugin/SketchPlugin_Arc.cpp
index be7ad7dc7..c72230a16 100644
--- a/src/SketchPlugin/SketchPlugin_Arc.cpp
+++ b/src/SketchPlugin/SketchPlugin_Arc.cpp
@@ -1,8 +1,21 @@
-// Copyright (C) 2014-20xx CEA/DEN, EDF R&D -->
-
-// File:        SketchPlugin_Arc.cpp
-// Created:     26 Apr 2014
-// Author:      Artem ZHIDKOV
+// Copyright (C) 2014-2023  CEA/DEN, EDF R&D
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+//
+// See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
+//
 
 #include "SketchPlugin_Arc.h"
 #include "SketchPlugin_Sketch.h"
@@ -37,302 +50,114 @@
 #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;
-
-namespace {
-  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 SketchPlugin_Arc::PASSED_POINT_ID();
-    }
-
-    static const std::string DUMMY;
-    return DUMMY;
-  }
-}
+#include <cmath>
 
+static const double tolerance = 1e-7;
+static const double paramTolerance = 1.e-4;
+static const double PI = 3.141592653589793238463;
 
 
 SketchPlugin_Arc::SketchPlugin_Arc()
-    : SketchPlugin_SketchEntity()
+: SketchPlugin_SketchEntity()
 {
-  myStartUpdate = false;
-  myEndUpdate = false;
-  // default values
-  myXEndBefore = 0;
-  myYEndBefore = 0;
-
-  myParamBefore = PI * 2.0;
+  myParamBefore = 0.0;
 }
 
 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(END_ID(), GeomDataAPI_Point2D::typeId());
+
   data()->addAttribute(EXTERNAL_ID(), ModelAPI_AttributeSelection::typeId());
   ModelAPI_Session::get()->validators()->registerNotObligatory(getKind(), EXTERNAL_ID());
 
-  AttributeBooleanPtr isInversed = std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(
-    data()->addAttribute(INVERSED_ID(), ModelAPI_AttributeBoolean::typeId()));
-
-  // get the initial values
-  if (anEndAttr->isInitialized()) {
-    myXEndBefore = anEndAttr->x();
-    myYEndBefore = anEndAttr->y();
-  }
-
-  AttributeStringPtr anArcType = std::dynamic_pointer_cast<ModelAPI_AttributeString>(
-    data()->addAttribute(ARC_TYPE(), ModelAPI_AttributeString::typeId()));
+  AttributeBooleanPtr isReversed = std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(
+    data()->addAttribute(REVERSED_ID(), ModelAPI_AttributeBoolean::typeId()));
 
-  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());
 
   // set after all to avoid in attributeChanged reference to not existing attributes
-  if (!isInversed->isInitialized())
-    isInversed->setValue(false);
-  anArcType->setValue(ARC_TYPE_CENTER_START_END());
+  if (!isReversed->isInitialized()) {
+    isReversed->setValue(false);
+  }
 }
 
 void SketchPlugin_Arc::execute()
 {
   SketchPlugin_Sketch* aSketch = sketch();
-  // 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()) {
-    bool hasResult = lastResult().get() != NULL;
-
-    // compute a circle point in 3D view
-    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::vertex(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()));
-
-    // compute and change the arc end point
-    std::shared_ptr<GeomDataAPI_Point2D> anEndAttr = std::dynamic_pointer_cast<
-        GeomDataAPI_Point2D>(data()->attribute(END_ID()));
+  if(!aSketch) {
+    return;
+  }
+
+  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()));
+  if(!aCenterAttr->isInitialized() || !aStartAttr->isInitialized() || !anEndAttr->isInitialized()) {
+    return;
+  }
+
+  // Make a visible point.
+  SketchPlugin_Sketch::createPoint2DResult(this, sketch(), CENTER_ID(), 0);
+
+  // Make a visible arc.
+  std::shared_ptr<GeomAPI_Pnt> aCenter(aSketch->to3D(aCenterAttr->x(), aCenterAttr->y()));
+  std::shared_ptr<GeomAPI_Pnt> aStart(aSketch->to3D(aStartAttr->x(), aStartAttr->y()));
+  std::shared_ptr<GeomAPI_Pnt> anEnd(aSketch->to3D(anEndAttr->x(), anEndAttr->y()));
+  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(new GeomAPI_Dir(aNDir->x(), aNDir->y(), aNDir->z()));
+
+  if (myParamBefore == 0) { // parameter has not been calculate yet
     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()));
-
-    // compute end parameter
     aCircleForArc->parameter(anEndAttr->pnt(), paramTolerance, myParamBefore);
+  }
 
-    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);
-    }
+  bool isReversed = boolean(REVERSED_ID())->value();
 
-    if (aCircleShape) {
-      std::shared_ptr<ModelAPI_ResultConstruction> aConstr2 = document()->createConstruction(
-          data(), 1);
-      aConstr2->setShape(aCircleShape);
-      aConstr2->setIsInHistory(false);
-      setResult(aConstr2, 1);
-    }
+  GeomEdgePtr anArcShape;
+  if (fabs(myParamBefore - 2.0 * PI) < paramTolerance) {
+    anArcShape = GeomAlgoAPI_EdgeBuilder::lineCircle(aCenter, aNormal, aStart->distance(aCenter));
+    myParamBefore = 0;
+  } else {
+    anArcShape = isReversed ?
+      GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, anEnd, aStart, aNormal)
+    : GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, aStart, anEnd, aNormal);
   }
-}
 
-AISObjectPtr SketchPlugin_Arc::getAISObject(AISObjectPtr 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()));
-
-      std::list<std::shared_ptr<GeomAPI_Shape> > aShapes;
-      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()) {
-              if (aEndAttr->isInitialized() && //
-                  aEndAttr->pnt()->distance(aStartAttr->pnt()) > tolerance) {
-                aEndPoint = aSketch->to3D(aEndAttr->x(), aEndAttr->y());
-                std::shared_ptr<GeomDataAPI_Point2D> aPassedAttr =
-                  std::dynamic_pointer_cast<GeomDataAPI_Point2D>(
-                  data()->attribute(PASSED_POINT_ID()));
-                if (!aPassedAttr->isInitialized()) {
-                  // calculate the appropriate center for the presentation
-                  // check that center is bad for the current start and end and must be recomputed
-                  std::shared_ptr<GeomAPI_Circ2d> aCircleForArc(new GeomAPI_Circ2d(
-                    aCenterAttr->pnt(), aStartAttr->pnt()));
-                  std::shared_ptr<GeomAPI_Pnt2d> aProjection =
-                    aCircleForArc->project(aEndAttr->pnt());
-                  if (!aProjection.get() || aEndAttr->pnt()->distance(aProjection) > tolerance) {
-                    std::shared_ptr<GeomAPI_XY> aDir =
-                      aEndAttr->pnt()->xy()->decreased(aStartAttr->pnt()->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> aCenterXY = aStartAttr->pnt()->xy()->added(aDir);
-                    aCenter = aSketch->to3D(aCenterXY->x(), aCenterXY->y());
-                  }
-                }
-              } else { // issue #1695: don't display circle if initialized only start point
-                return AISObjectPtr();
-              }
-            }
-            AttributeBooleanPtr isInversed =
-              std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(attribute(INVERSED_ID()));
-
-            std::shared_ptr<GeomAPI_Shape> aCircleShape =
-              (isInversed->isInitialized() && isInversed->value()) ?
-                GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, aEndPoint, aStartPoint, aNormal) :
-                GeomAlgoAPI_EdgeBuilder::lineCircleArc(aCenter, aStartPoint, aEndPoint, aNormal);
-
-            if (aCircleShape)
-              aShapes.push_back(aCircleShape);
-          }
-        }
-        // make a visible point
-        std::shared_ptr<GeomAPI_Shape> aCenterPointShape =
-          GeomAlgoAPI_PointBuilder::vertex(aCenter);
-        aShapes.push_back(aCenterPointShape);
-      }
-      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);
-        double aDeflection = Config_PropManager::real("Visualization", "construction_deflection",
-                                             ModelAPI_ResultConstruction::DEFAULT_DEFLECTION());
-        anAIS->setDeflection(aDeflection);
-        anAIS->setWidth(3);
-        return anAIS;
+  // calculate tolerances for start and end points of the arc and set them to the result shape
+  // (this is done to fix gaps which appear because of inaccurate computation of arcs in PlaneGCS,
+  // which leads to difference in SketchPlugin_Arc attributes and boundary points of result shape)
+  if (anArcShape) {
+    for (int ind = 0; ind < 2; ++ind) {
+      bool isFirst = ind == 0;
+      GeomPointPtr anArcBndPoint = isFirst == isReversed ? anEnd : aStart;
+      GeomPointPtr aShapePoint = isFirst ? anArcShape->firstPoint() : anArcShape->lastPoint();
+      double aDistance = anArcBndPoint->distance(aShapePoint);
+      // avoid setting too high tolerance because it may be caused by incomplete update of an arc
+      if (aDistance > tolerance && aDistance < 100. * tolerance) {
+        if (isFirst)
+          anArcShape->setFirstPointTolerance(aDistance);
+        else
+          anArcShape->setLastPointTolerance(aDistance);
       }
     }
   }
-  return AISObjectPtr();
-}
 
-void SketchPlugin_Arc::move(double theDeltaX, double theDeltaY)
-{
-  std::shared_ptr<ModelAPI_Data> aData = data();
-  if (!aData->isValid())
-    return;
-
-  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()));
-  if (aPoint2->isInitialized())
-    aPoint2->move(theDeltaX, theDeltaY);
-
-  std::shared_ptr<GeomDataAPI_Point2D> aPoint3 = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(
-      aData->attribute(SketchPlugin_Arc::END_ID()));
-  if (aPoint3->isInitialized())
-    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()));
-  if (aPoint1->isInitialized())
-    aPoint1->move(theDeltaX, theDeltaY);
-
-  std::shared_ptr<GeomDataAPI_Point2D> aPassedPoint =
-      std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aData->attribute(PASSED_POINT_ID()));
-  if (aPassedPoint->isInitialized())
-    aPassedPoint->move(theDeltaX, theDeltaY);
-  aData->blockSendAttributeUpdated(false);
-}
-
-bool SketchPlugin_Arc::isFixed() {
-  return data()->selection(EXTERNAL_ID())->context().get() != NULL;
+  std::shared_ptr<ModelAPI_ResultConstruction> aResult = document()->createConstruction(data(), 1);
+  aResult->setShape(anArcShape);
+  aResult->setIsInHistory(false);
+  setResult(aResult, 1);
 }
 
-bool SketchPlugin_Arc::isFeatureValid()
+bool SketchPlugin_Arc::isFixed()
 {
-  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;
+  return data()->selection(EXTERNAL_ID())->context().get() != NULL;
 }
 
 void SketchPlugin_Arc::attributeChanged(const std::string& theID)
@@ -343,96 +168,68 @@ void SketchPlugin_Arc::attributeChanged(const std::string& theID)
       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()) {
+
+  // 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();
-    if (!aSelection) {
+    if(!aSelection) {
       // empty shape in selection shows that the shape is equal to context
       ResultPtr anExtRes = selection(EXTERNAL_ID())->context();
-      if (anExtRes)
+      if(anExtRes) {
         aSelection = anExtRes->shape();
+      }
     }
     // update arguments due to the selection value
-    if (aSelection && !aSelection->isNull() && aSelection->isEdge()) {
+    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()) {
+      if(aCirc.get()) {
+        bool aWasBlocked = data()->blockSendAttributeUpdated(true);
+        aCenterAttr->setValue(sketch()->to2D(aCirc->center()));
         aStartAttr->setValue(sketch()->to2D(anEdge->firstPoint()));
         anEndAttr->setValue(sketch()->to2D(anEdge->lastPoint()));
-        aCenterAttr->setValue(sketch()->to2D(aCirc->center()));
-
-        data()->real(RADIUS_ID())->setValue(aCirc->radius());
-        double aStartAngle, aEndAngle;
-        anEdge->getRange(aStartAngle, aEndAngle);
-        data()->real(ANGLE_ID())->setValue(aEndAngle - aStartAngle);
-        myParamBefore = aEndAngle;
-        adjustPeriod(myParamBefore);
-      }
-    }
-    return;
-  }
-  AttributeStringPtr aTypeAttr =
-      std::dynamic_pointer_cast<ModelAPI_AttributeString>(attribute(ARC_TYPE()));
-
-  // this is before others since here end attribute may be changed, but with the special behavior
-  if (aTypeAttr->value() == 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()) {
-      // 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();
-      if (aTangPnt2d->isEqual(anEndAttr->pnt()))
-        return;
-      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) {
-        data()->blockSendAttributeUpdated(true);
-        aCenterAttr->setValue(aCenter);
-        aStartAttr->setValue(aTangPnt2d);
-        data()->blockSendAttributeUpdated(false);
+        data()->blockSendAttributeUpdated(aWasBlocked, false);
+
+        std::shared_ptr<GeomAPI_Circ2d> aCircle2d =
+          std::shared_ptr<GeomAPI_Circ2d>(new GeomAPI_Circ2d(aCenterAttr->pnt(),
+                                                             aStartAttr->pnt()));
+
+        double anEndParam = 0.0;
+        aCircle2d->parameter(anEndAttr->pnt(), paramTolerance, anEndParam);
+        myParamBefore = anEndParam;
+
+        double aMidParam  = anEndParam / 2.0;
+        std::shared_ptr<GeomAPI_Pnt2d> aMidPnt2d;
+        aCircle2d->D0(aMidParam, aMidPnt2d);
+        std::shared_ptr<GeomAPI_Pnt> aMinPnt = sketch()->to3D(aMidPnt2d->x(), aMidPnt2d->y());
+        double aStartParam = 0.0;
+        aCirc->parameter(anEdge->firstPoint(), paramTolerance, aStartParam);
+        aCirc->parameter(aMinPnt, paramTolerance, aMidParam);
+        aCirc->parameter(anEdge->lastPoint(), paramTolerance, anEndParam);
+
+        // adjust period
+        anEndParam -= aStartParam;
+        aMidParam -= aStartParam;
+        if (anEndParam < 0.0)
+          anEndParam += 2.0 * PI;
+        if (aMidParam < 0.0)
+          aMidParam += 2.0 * PI;
+
+        aWasBlocked = data()->blockSendAttributeUpdated(true);
+        if(aMidParam < anEndParam) {
+          setReversed(false);
+        } else {
+          setReversed(true);
+        }
+        data()->blockSendAttributeUpdated(aWasBlocked, false);
       }
-
-      tangencyArcConstraints();
     }
-    return;
-  }
-
-  // if changed the base attributes, update all other (is necessary) without recursion
-  if (theID == CENTER_ID() || theID == START_ID() || theID == END_ID() || theID == ARC_TYPE()) {
-    if (!isFeatureValid())
+  } else if(theID == CENTER_ID() || theID == START_ID() || theID == END_ID()) {
+    if(!aCenterAttr->isInitialized()
+      || !aStartAttr->isInitialized()
+      || !anEndAttr->isInitialized()) {
       return;
+    }
     std::shared_ptr<GeomAPI_Pnt2d> aCenter = aCenterAttr->pnt();
     std::shared_ptr<GeomAPI_Pnt2d> aStart = aStartAttr->pnt();
     std::shared_ptr<GeomAPI_Pnt2d> anEnd = anEndAttr->pnt();
@@ -441,326 +238,60 @@ void SketchPlugin_Arc::attributeChanged(const std::string& theID)
       return;
     std::shared_ptr<GeomAPI_Circ2d> aCircleForArc(new GeomAPI_Circ2d(aCenter, aStart));
 
-    data()->blockSendAttributeUpdated(true);
-    // The Arc end point is projected
-    // on the circle formed by center and start points
+    // Do not recalculate REVERSED flag if the arc is not consistent
     std::shared_ptr<GeomAPI_Pnt2d> aProjection = aCircleForArc->project(anEnd);
-    if (aProjection && anEnd->distance(aProjection) > tolerance) {
-      anEndAttr->setValue(aProjection);
-      anEnd = aProjection;
-    }
-    // update all other attributes due to the base attributes values
-    if (aTypeAttr->value() == ARC_TYPE_THREE_POINTS()) {
-      // update passed point due to start, end and center
-      if (aCenter->distance(aStart) > tolerance && aCenter->distance(anEnd) > tolerance) {
-        // project passed point t othe circle
-        std::shared_ptr<GeomDataAPI_Point2D> aPassedAttr =
-          std::dynamic_pointer_cast<GeomDataAPI_Point2D>(data()->attribute(PASSED_POINT_ID()));
-        if (aPassedAttr->isInitialized()) {
-          std::shared_ptr<GeomAPI_Pnt2d> aProjection = aCircleForArc->project(aPassedAttr->pnt());
-          if (aProjection && aPassedAttr->pnt()->distance(aProjection) > tolerance) {
-            aPassedAttr->setValue(aProjection);
+    if (aProjection && anEnd->distance(aProjection) <= tolerance) {
+      double aParameterNew = 0.0;
+      if(aCircleForArc->parameter(anEnd, paramTolerance, aParameterNew)) {
+        bool aWasBlocked = data()->blockSendAttributeUpdated(true);
+        if(myParamBefore <= PI / 2.0 && aParameterNew >= PI * 1.5) {
+          if(!boolean(REVERSED_ID())->value()) {
+            boolean(REVERSED_ID())->setValue(true);
           }
-        } else { // initialize it by some middle - value
-          std::shared_ptr<GeomAPI_Dir2d> aStartDir(new GeomAPI_Dir2d(
-            aStart->xy()->decreased(aCenter->xy())));
-          std::shared_ptr<GeomAPI_Dir2d> aEndDir(new GeomAPI_Dir2d(
-            anEnd->xy()->decreased(aCenter->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());
+        } else if(myParamBefore >= PI * 1.5 && aParameterNew <= PI / 2.0) {
+          if(boolean(REVERSED_ID())->value()) {
+            boolean(REVERSED_ID())->setValue(false);
           }
-          std::shared_ptr<GeomAPI_Dir2d> aMidDir(new GeomAPI_Dir2d(aMidDirXY));
-          if ((aStartDir->cross(aMidDir) > 0) ^ !isReversed())
-            aMidDir->reverse();
-          std::shared_ptr<GeomAPI_XY> aPassedPnt =
-            aCenter->xy()->added(aMidDir->xy()->multiplied(aCenter->distance(aStart)));
-          std::dynamic_pointer_cast<GeomDataAPI_Point2D>(data()->attribute(PASSED_POINT_ID()))->
-            setValue(aPassedPnt->x(), aPassedPnt->y());
         }
+        data()->blockSendAttributeUpdated(aWasBlocked, false);
       }
+      if (fabs(aParameterNew) < paramTolerance ||
+          fabs(aParameterNew - 2.0 * PI) < paramTolerance)
+        aParameterNew = 2.0 * PI;
+      myParamBefore = aParameterNew;
     }
-    // update radius and angle
-    AttributeDoublePtr aRadiusAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
-        data()->attribute(RADIUS_ID()));
-    aRadiusAttr->setValue(aRadius);
-    AttributeDoublePtr anAngleAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
-        data()->attribute(ANGLE_ID()));
-    std::shared_ptr<GeomAPI_Circ2d> aCircle(new GeomAPI_Circ2d(aCenter, aStart));
-    double aStartParam, aEndParam;
-    aCircle->parameter(aStart, paramTolerance, aStartParam);
-    aCircle->parameter(anEnd, paramTolerance, aEndParam);
-    adjustPeriod(aStartParam);
-    adjustPeriod(aEndParam);
-    // use the passed point for the angle calculation
-    if (aTypeAttr->value() == ARC_TYPE_THREE_POINTS()) {
-      std::shared_ptr<GeomDataAPI_Point2D> aPassedAttr =
-        std::dynamic_pointer_cast<GeomDataAPI_Point2D>(data()->attribute(PASSED_POINT_ID()));
-      double aPassedParam;
-      aCircle->parameter(aPassedAttr->pnt(), paramTolerance, aPassedParam);
-      adjustPeriod(aPassedParam);
-      double aNewAngle = aPassedParam >= aStartParam && aPassedParam <= aEndParam ?
-        ((aEndParam - aStartParam) * 180.0 / PI) :
-        ((aEndParam - aStartParam - 2.0 * PI) * 180.0 / PI);
-      if (!anAngleAttr->isInitialized() || fabs(aNewAngle - anAngleAttr->value()) > tolerance)
-        anAngleAttr->setValue(aNewAngle);
-    } else {
-      double aNewAngle = (aEndParam - aStartParam) * 180.0 / PI;
-      if (!anAngleAttr->isInitialized() || fabs(aNewAngle - anAngleAttr->value()) > tolerance)
-        anAngleAttr->setValue(aNewAngle);
-    }
-
-    // calculate arc aperture and change the Inversed flag if needed
-    AttributeBooleanPtr isInversed =
-        std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(attribute(INVERSED_ID()));
-    double aParameterNew = aEndParam - aStartParam;
-    if (((0 <= myParamBefore && myParamBefore <= PI / 2.0) || 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);
-    myParamBefore = aParameterNew;
-
-    // do not need to inform that other parameters were changed in this basis mode: these arguments
-    // change is enough
-    data()->blockSendAttributeUpdated(false, false);
-    return;
   }
 
-  if (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 == 3) {
-      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);
+  double aRadius = 0;
+  double anAngle = 0;
+  if(aCenterAttr->isInitialized() && aStartAttr->isInitialized()) {
+    aRadius = aCenterAttr->pnt()->distance(aStartAttr->pnt());
+    if(anEndAttr->isInitialized()) {
+      if(aStartAttr->pnt()->isEqual(anEndAttr->pnt())) {
+        anAngle = 360;
+      } else {
+        GeomAPI_Circ2d aCircleForArc(aCenterAttr->pnt(), aStartAttr->pnt());
+        double aStartParam, anEndParam;
+        aCircleForArc.parameter(aStartAttr->pnt(), paramTolerance, aStartParam);
+        aCircleForArc.parameter(anEndAttr->pnt(), paramTolerance, anEndParam);
+        anAngle = (anEndParam - aStartParam) / PI * 180.0;
+        if(isReversed()) anAngle = 360.0 - anAngle;
       }
     }
-    data()->blockSendAttributeUpdated(false);
-    return;
   }
 
-  if (theID == RADIUS_ID()) {
-    if (!aStartAttr->isInitialized() || !anEndAttr->isInitialized() ||
-        !aCenterAttr->isInitialized())
-      return;
-    // move center and passed point
-    std::shared_ptr<GeomAPI_Pnt2d> aStart = aStartAttr->pnt();
-    std::shared_ptr<GeomAPI_Pnt2d> anEnd = anEndAttr->pnt();
-    std::shared_ptr<GeomAPI_Pnt2d> aCenter = aCenterAttr->pnt();
-    if (aStart->distance(aCenter) < tolerance || anEnd->distance(aCenter) < tolerance)
-      return;
-    AttributeDoublePtr aRadiusAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
-        data()->attribute(RADIUS_ID()));
-    double aRadius = aRadiusAttr->value();
-
-    data()->blockSendAttributeUpdated(true);
-    std::shared_ptr<GeomAPI_Dir2d>
-      aStartDir(new GeomAPI_Dir2d(aStart->xy()->decreased(aCenter->xy())));
-    std::shared_ptr<GeomAPI_XY>
-      aNewStart = aStartDir->xy()->multiplied(aRadius)->added(aCenter->xy());
-    aStartAttr->setValue(aNewStart->x(), aNewStart->y());
-    std::shared_ptr<GeomAPI_Dir2d>
-      anEndDir(new GeomAPI_Dir2d(anEnd->xy()->decreased(aCenter->xy())));
-    std::shared_ptr<GeomAPI_XY>
-      aNewEnd = anEndDir->xy()->multiplied(aRadius)->added(aCenter->xy());
-    anEndAttr->setValue(aNewEnd->x(), aNewEnd->y());
-    data()->blockSendAttributeUpdated(false);
-    return;
-  }
-  if (theID == ANGLE_ID()) {
-    if (!aStartAttr->isInitialized() || !aCenterAttr->isInitialized())
-      return;
-    AttributeDoublePtr anAngleAttr = std::dynamic_pointer_cast<ModelAPI_AttributeDouble>(
-        data()->attribute(ANGLE_ID()));
-    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());
-    data()->blockSendAttributeUpdated(false);
-    return;
-  }
+  bool aWasBlocked = data()->blockSendAttributeUpdated(true);
+  real(RADIUS_ID())->setValue(aRadius);
+  real(ANGLE_ID())->setValue(anAngle);
+  data()->blockSendAttributeUpdated(aWasBlocked, false);
 }
 
 void SketchPlugin_Arc::setReversed(bool isReversed)
 {
-  std::dynamic_pointer_cast<ModelAPI_AttributeBoolean>(
-    attribute(INVERSED_ID()))->setValue(isReversed);
-  myParamBefore = 0.0;
+  boolean(REVERSED_ID())->setValue(isReversed);
 }
 
 bool SketchPlugin_Arc::isReversed()
 {
-  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();
-      FeaturePtr anOtherFeature = ModelAPI_Feature::feature(anOtherObject);
-      if (anOtherPoint->owner() == anOtherFeature) {
-        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();
-    std::set<FeaturePtr> aFeaturesToBeRemoved;
-    for (aCIt = aCoincidence.begin(); aCIt != aCoincidence.end(); ++aCIt)
-      aFeaturesToBeRemoved.insert(*aCIt);
-    for (aTIt = aTangency.begin(); aTIt != aTangency.end(); ++aTIt)
-      aFeaturesToBeRemoved.insert(*aTIt);
-    ModelAPI_Tools::removeFeaturesAndReferences(aFeaturesToBeRemoved);
-    // 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 aCreateEvent = Events_Loop::eventByName(EVENT_OBJECT_CREATED);
-    bool isCreateFlushed = Events_Loop::loop()->isFlushed(aCreateEvent);
-    if (isCreateFlushed)
-      Events_Loop::loop()->setFlushed(aCreateEvent, 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, aCreateEvent);
-
-    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, aCreateEvent);
-
-    // Send events to update the sub-features by the solver.
-    if(isCreateFlushed)
-      Events_Loop::loop()->setFlushed(aCreateEvent, true);
-    else
-      Events_Loop::loop()->flush(aCreateEvent);
-  }
+  return boolean(REVERSED_ID())->value();
 }