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Correct processing of the fixed arc in PlaneGCS (issue #1280)
[modules/shaper.git] / src / SketchPlugin / SketchPlugin_Validators.cpp
index ee7121371bf94d53d0ac811250dfd9527adcd6a1..a29070b1f7e2f8b48834ebb1ef3133e7fe01cc29 100755 (executable)
 #include <ModelAPI_Validator.h>
 #include <ModelAPI_AttributeDouble.h>
 #include <ModelAPI_AttributeRefAttr.h>
+
+#include <ModelAPI_AttributeRefAttrList.h>
 #include <ModelAPI_AttributeRefList.h>
 #include <ModelAPI_AttributeSelectionList.h>
 #include <ModelAPI_AttributeString.h>
 #include <ModelAPI_Session.h>
+#include <ModelAPI_ResultConstruction.h>
 
-#include <GeomValidators_ShapeType.h>
-
+#include <GeomAPI_Vertex.h>
 #include <GeomDataAPI_Point2D.h>
 
+const double tolerance = 1.e-7;
 
 bool SketchPlugin_DistanceAttrValidator::isValid(const AttributePtr& theAttribute, 
                                                  const std::list<std::string>& theArguments,
@@ -56,7 +59,7 @@ bool SketchPlugin_DistanceAttrValidator::isValid(const AttributePtr& theAttribut
     ObjectPtr anObject = aRefAttr->object();
 
     const ModelAPI_AttributeValidator* aShapeValidator = 
-      dynamic_cast<const GeomValidators_ShapeType*>(aFactory->validator("GeomValidators_ShapeType"));
+      dynamic_cast<const ModelAPI_AttributeValidator*>(aFactory->validator("GeomValidators_ShapeType"));
     std::list<std::string> anArguments;
     anArguments.push_back("circle");
     std::string aCircleError;
@@ -90,6 +93,49 @@ bool SketchPlugin_DistanceAttrValidator::isValid(const AttributePtr& theAttribut
   return true;
 }
 
+
+static bool hasCoincidentPoint(FeaturePtr theFeature1, FeaturePtr theFeature2)
+{
+  FeaturePtr aConstrFeature;
+  std::list<AttributePtr> anAttrList;
+  if (theFeature1->getKind() == SketchPlugin_Circle::ID() ||
+      theFeature2->getKind() == SketchPlugin_Circle::ID())
+    return false;
+  if (theFeature2->getKind() == SketchPlugin_Line::ID()) {
+    anAttrList.push_back(theFeature2->attribute(SketchPlugin_Line::START_ID()));
+    anAttrList.push_back(theFeature2->attribute(SketchPlugin_Line::END_ID()));
+  } else if (theFeature2->getKind() == SketchPlugin_Arc::ID()) {
+    anAttrList.push_back(theFeature2->attribute(SketchPlugin_Arc::START_ID()));
+    anAttrList.push_back(theFeature2->attribute(SketchPlugin_Arc::END_ID()));
+  }
+
+  const std::set<AttributePtr>& aRefsList = theFeature1->data()->refsToMe();
+  std::set<AttributePtr>::const_iterator aRefIt = aRefsList.begin();
+  for (; aRefIt != aRefsList.end(); ++aRefIt) {
+    aConstrFeature = std::dynamic_pointer_cast<ModelAPI_Feature>((*aRefIt)->owner());
+    if (aConstrFeature->getKind() != SketchPlugin_ConstraintCoincidence::ID())
+      continue;
+    AttributeRefAttrPtr aRefAttr = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(*aRefIt);
+    AttributePtr anAttr = aRefAttr->attr();
+    if (anAttr->id() == SketchPlugin_Arc::CENTER_ID())
+      continue;
+
+    anAttr = aConstrFeature->attribute(SketchPlugin_Constraint::ENTITY_A());
+    if (anAttr == *aRefIt)
+      anAttr = aConstrFeature->attribute(SketchPlugin_Constraint::ENTITY_B());
+
+    aRefAttr = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(anAttr);
+    if (!aRefAttr)
+      continue;
+    anAttr = aRefAttr->attr();
+    for (std::list<AttributePtr>::const_iterator anIt = anAttrList.begin();
+         anIt != anAttrList.end(); ++anIt)
+      if (*anIt == anAttr)
+        return true;
+  }
+  return false;
+}
+
 bool SketchPlugin_TangentAttrValidator::isValid(const AttributePtr& theAttribute, 
                                                 const std::list<std::string>& theArguments,
                                                 std::string& theError) const
@@ -115,11 +161,19 @@ bool SketchPlugin_TangentAttrValidator::isValid(const AttributePtr& theAttribute
     AttributeRefAttrPtr aOtherAttr = anAttributeFeature->data()->refattr(aParamA);
     ObjectPtr aOtherObject = aOtherAttr->object();
     FeaturePtr aOtherFea = ModelAPI_Feature::feature(aOtherObject);
+    if (!aOtherFea)
+      return true;
+
+    if ((aRefFea->getKind() == SketchPlugin_Arc::ID() ||
+        aOtherFea->getKind() == SketchPlugin_Arc::ID()) &&
+        !hasCoincidentPoint(aRefFea, aOtherFea))
+      return false;
 
     if (aRefFea->getKind() == SketchPlugin_Line::ID()) {
-      if (aOtherFea->getKind() != SketchPlugin_Arc::ID()) {
-        theError = "It refers to a " + SketchPlugin_Line::ID() + ", but " + aParamA + " is not an "
-          + SketchPlugin_Arc::ID();
+      if (aOtherFea->getKind() != SketchPlugin_Arc::ID() &&
+          aOtherFea->getKind() != SketchPlugin_Circle::ID()) {
+        theError = "It refers to a " + SketchPlugin_Line::ID() + ", but " + aParamA + " is neither an "
+          + SketchPlugin_Arc::ID() + " nor " + SketchPlugin_Circle::ID();
         return false;
       }
     }
@@ -131,9 +185,16 @@ bool SketchPlugin_TangentAttrValidator::isValid(const AttributePtr& theAttribute
         return false;
       }
     }
+    else if (aRefFea->getKind() == SketchPlugin_Circle::ID()) {
+      if (aOtherFea->getKind() != SketchPlugin_Line::ID()) {
+        theError = "It refers to an " + SketchPlugin_Circle::ID() + ", but " + aParamA + " is not a "
+          + SketchPlugin_Line::ID();
+        return false;
+      }
+    }
     else {
-      theError = "It refers to " + aRefFea->getKind() + "but should refer to " + SketchPlugin_Line::ID()
-        + " or " + SketchPlugin_Arc::ID();
+      theError = "It refers to " + aRefFea->getKind() + "but should refer to " + SketchPlugin_Line::ID()
+        + " or " + SketchPlugin_Arc::ID() + " or " + SketchPlugin_Circle::ID();
       return false;
     }
     return true;
@@ -146,7 +207,7 @@ bool SketchPlugin_TangentAttrValidator::isValid(const AttributePtr& theAttribute
   return true;
 }
 
-bool SketchPlugin_NotFixedValidator::isValid(const AttributePtr& theAttribute, 
+bool SketchPlugin_NotFixedValidator::isValid(const AttributePtr& theAttribute,
                                              const std::list<std::string>& theArguments,
                                              std::string& theError) const
 {
@@ -280,7 +341,6 @@ bool SketchPlugin_MirrorAttrValidator::isValid(const AttributePtr& theAttribute,
   return true;
 }
 
-
 bool SketchPlugin_CoincidenceAttrValidator::isValid(const AttributePtr& theAttribute, 
                                                     const std::list<std::string>& theArguments,
                                                     std::string& theError) const
@@ -403,102 +463,231 @@ bool SketchPlugin_FilletVertexValidator::isValid(const AttributePtr& theAttribut
                                                  const std::list<std::string>& theArguments,
                                                  std::string& theError) const
 {
-  if(!theAttribute.get()) {
+  if(!theAttribute.get() || !theAttribute->isInitialized()) {
+    theError = "Error: List of points is not initialized.";
     return false;
   }
 
-  AttributeRefAttrPtr aBase = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(theAttribute);
-  if(aBase->isObject()) {
+  FeaturePtr aFilletFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(theAttribute->owner());
+  AttributeRefAttrListPtr aPointsRefList = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttrList>(theAttribute);
+  if(aPointsRefList->size() == 0) {
+    theError = "Error: List of points is empty.";
     return false;
   }
 
-  // If we alredy have some result then all ok
-  FeaturePtr aFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(theAttribute->owner());
-  AttributePtr aBaseLinesAttribute = aFeature->attribute(SketchPlugin_Constraint::ENTITY_C());
-  AttributeRefListPtr aRefListOfBaseLines = std::dynamic_pointer_cast<ModelAPI_AttributeRefList>(aBaseLinesAttribute);
-  if(aRefListOfBaseLines->list().size() == 2) {
-    return true;
-  }
+  AttributeRefAttrListPtr aBasePointsRefList = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttrList>(
+    aFilletFeature->attribute(SketchPlugin_Constraint::ENTITY_C()));
+  AttributeRefListPtr aResultEdgesRefList = std::dynamic_pointer_cast<ModelAPI_AttributeRefList>(
+    aFilletFeature->attribute(SketchPlugin_Constraint::ENTITY_B()));
+
+  std::list<std::pair<ObjectPtr, AttributePtr>> aPointsList = aPointsRefList->list();
+  for(std::list<std::pair<ObjectPtr, AttributePtr>>::const_iterator anIt = aPointsList.cbegin(); anIt != aPointsList.cend(); anIt++) {
+    ObjectPtr anObject = (*anIt).first;
+    AttributePtr aPointAttribute = (*anIt).second;
+
+    // If we alredy have some result then:
+    // - if it is the same point all ok, just skip it
+    // - if it is point on the fillet arc then it is not valid
+    if(aBasePointsRefList->size() > 0) {
+      if(aBasePointsRefList->isInList(aPointAttribute)) {
+        continue;
+      }
 
-  AttributePtr anAttrBase = aBase->attr();
-  const std::set<AttributePtr>& aRefsList = anAttrBase->owner()->data()->refsToMe();
-  std::set<AttributePtr>::const_iterator aIt;
-  FeaturePtr aCoincident;
-  for (aIt = aRefsList.cbegin(); aIt != aRefsList.cend(); ++aIt) {
-    std::shared_ptr<ModelAPI_Attribute> aAttr = (*aIt);
-    FeaturePtr aConstrFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(aAttr->owner());
-    if (aConstrFeature->getKind() == SketchPlugin_ConstraintCoincidence::ID()) {
-      AttributeRefAttrPtr anAttrRefA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
-        aConstrFeature->attribute(SketchPlugin_ConstraintCoincidence::ENTITY_A()));
-      AttributeRefAttrPtr anAttrRefB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
-        aConstrFeature->attribute(SketchPlugin_ConstraintCoincidence::ENTITY_B()));
-      if(anAttrRefA.get() && !anAttrRefA->isObject()) {
-        AttributePtr anAttrA = anAttrRefA->attr();
-        if(anAttrBase == anAttrA) {
-          aCoincident = aConstrFeature;
-          break;
+      // Check that selected point not on the one of the result fillet arc.
+      for(int anIndex = 0; anIndex < aBasePointsRefList->size(); anIndex++) {
+        if(aResultEdgesRefList->size() > 0) {
+          FeaturePtr aResultArc;
+          aResultArc = ModelAPI_Feature::feature(aResultEdgesRefList->object(anIndex * 3 + 2));
+          AttributePtr anArcStart = aResultArc->attribute(SketchPlugin_Arc::START_ID());
+          AttributePtr anArcEnd = aResultArc->attribute(SketchPlugin_Arc::END_ID());
+          std::shared_ptr<GeomAPI_Pnt2d> anArcStartPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(anArcStart)->pnt();
+          std::shared_ptr<GeomAPI_Pnt2d> anArcEndPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(anArcEnd)->pnt();
+          std::shared_ptr<GeomAPI_Pnt2d> aSelectedPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aPointAttribute)->pnt();
+          double aDistSelectedArcStart = aSelectedPnt->distance(anArcStartPnt);
+          double aDistSelectedArcEnd = aSelectedPnt->distance(anArcEndPnt);
+          if(aDistSelectedArcStart < tolerance || aDistSelectedArcEnd < tolerance) {
+            return false;
+          }
         }
       }
-      if(anAttrRefA.get() && !anAttrRefB->isObject()) {
-        AttributePtr anAttrB = anAttrRefB->attr();
-        if(anAttrBase == anAttrB) {
-          aCoincident = aConstrFeature;
-          break;
+    }
+
+    // Obtain constraint coincidence for the fillet point.
+    const std::set<AttributePtr>& aRefsList = aPointAttribute->owner()->data()->refsToMe();
+    FeaturePtr aConstraintCoincidence;
+    for(std::set<AttributePtr>::const_iterator anIt = aRefsList.cbegin(); anIt != aRefsList.cend(); ++anIt) {
+      std::shared_ptr<ModelAPI_Attribute> aAttr = (*anIt);
+      FeaturePtr aConstrFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(aAttr->owner());
+      if (aConstrFeature->getKind() == SketchPlugin_ConstraintCoincidence::ID()) {
+        AttributeRefAttrPtr anAttrRefA = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          aConstrFeature->attribute(SketchPlugin_ConstraintCoincidence::ENTITY_A()));
+        AttributeRefAttrPtr anAttrRefB = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(
+          aConstrFeature->attribute(SketchPlugin_ConstraintCoincidence::ENTITY_B()));
+        if(anAttrRefA.get() && !anAttrRefA->isObject()) {
+          AttributePtr anAttrA = anAttrRefA->attr();
+          if(aPointAttribute == anAttrA) {
+            aConstraintCoincidence = aConstrFeature;
+            break;
+          }
+        }
+        if(anAttrRefB.get() && !anAttrRefB->isObject()) {
+          AttributePtr anAttrB = anAttrRefB->attr();
+          if(aPointAttribute == anAttrB) {
+            aConstraintCoincidence = aConstrFeature;
+            break;
+          }
         }
       }
     }
-  }
 
-  if(!aCoincident.get()) {
-    return false;
+    if(!aConstraintCoincidence.get()) {
+      theError = "Error: one of the selected point does not have coicidence.";
+      return false;
+    }
+
+    // Get coincides from constraint.
+    std::set<FeaturePtr> aCoinsides;
+    SketchPlugin_Tools::findCoincidences(aConstraintCoincidence,
+                                         SketchPlugin_ConstraintCoincidence::ENTITY_A(),
+                                         aCoinsides);
+    SketchPlugin_Tools::findCoincidences(aConstraintCoincidence,
+                                         SketchPlugin_ConstraintCoincidence::ENTITY_B(),
+                                         aCoinsides);
+
+    // Remove points from set of coincides.
+    std::set<FeaturePtr> aNewSetOfCoincides;
+    for(std::set<FeaturePtr>::iterator anIt = aCoinsides.begin(); anIt != aCoinsides.end(); ++anIt) {
+      if((*anIt)->getKind() == SketchPlugin_Line::ID() ||
+         (*anIt)->getKind() == SketchPlugin_Arc::ID()) {
+        aNewSetOfCoincides.insert(*anIt);
+      }
+    }
+    aCoinsides = aNewSetOfCoincides;
+
+    // If we still have more than two coincides remove auxilary entities from set of coincides.
+    if(aCoinsides.size() > 2) {
+      aNewSetOfCoincides.clear();
+      for(std::set<FeaturePtr>::iterator anIt = aCoinsides.begin(); anIt != aCoinsides.end(); ++anIt) {
+        if(!(*anIt)->boolean(SketchPlugin_SketchEntity::AUXILIARY_ID())->value()) {
+          aNewSetOfCoincides.insert(*anIt);
+        }
+      }
+      aCoinsides = aNewSetOfCoincides;
+    }
+
+    if(aCoinsides.size() != 2) {
+      theError = ("Error: One of the selected points does not have two suitable edges for fillet.");
+      return false;
+    }
+
+    // Check that lines not collinear
+    std::set<FeaturePtr>::iterator anIt = aCoinsides.begin();
+    FeaturePtr aFirstFeature = *anIt++;
+    FeaturePtr aSecondFeature = *anIt;
+    if(aFirstFeature->getKind() == SketchPlugin_Line::ID() && aSecondFeature->getKind() == SketchPlugin_Line::ID()) {
+      std::string aStartAttr = SketchPlugin_Line::START_ID();
+      std::string anEndAttr = SketchPlugin_Line::END_ID();
+      std::shared_ptr<GeomAPI_Pnt2d> aFirstStartPnt, aFirstEndPnt, aSecondStartPnt, aSecondEndPnt;
+      aFirstStartPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aFirstFeature->attribute(aStartAttr))->pnt();
+      aFirstEndPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aFirstFeature->attribute(anEndAttr))->pnt();
+      aSecondStartPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aSecondFeature->attribute(aStartAttr))->pnt();
+      aSecondEndPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aSecondFeature->attribute(anEndAttr))->pnt();
+      double aCheck1 = abs((aFirstEndPnt->x() - aFirstStartPnt->x()) * (aSecondStartPnt->y() - aFirstStartPnt->y()) -
+        (aSecondStartPnt->x() - aFirstStartPnt->x()) * (aFirstEndPnt->y() - aFirstStartPnt->y()));
+      double aCheck2 = abs((aFirstEndPnt->x() - aFirstStartPnt->x()) * (aSecondEndPnt->y() - aFirstStartPnt->y()) -
+        (aSecondEndPnt->x() - aFirstStartPnt->x()) * (aFirstEndPnt->y() - aFirstStartPnt->y()));
+      if(aCheck1 < 1.e-7 && aCheck2 < 1.e-7) {
+        return false;
+      }
+    }
   }
 
-  std::set<FeaturePtr> aCoinsideLines;
-  SketchPlugin_Tools::findCoincidences(aCoincident,
-                                       SketchPlugin_ConstraintCoincidence::ENTITY_A(),
-                                       aCoinsideLines);
-  SketchPlugin_Tools::findCoincidences(aCoincident,
-                                       SketchPlugin_ConstraintCoincidence::ENTITY_B(),
-                                       aCoinsideLines);
-  if(aCoinsideLines.size() < 2) {
+  return true;
+}
+
+bool SketchPlugin_MiddlePointAttrValidator::isValid(const AttributePtr& theAttribute, 
+                                                    const std::list<std::string>& theArguments,
+                                                    std::string& theError) const
+{
+  if (theAttribute->attributeType() != ModelAPI_AttributeRefAttr::typeId()) {
+    theError = "The attribute with the " + theAttribute->attributeType() + " type is not processed";
     return false;
   }
 
-  // Remove auxilary lines
-  if(aCoinsideLines.size() > 2) {
-    std::set<FeaturePtr> aNewLines;
-    for(std::set<FeaturePtr>::iterator anIt = aCoinsideLines.begin(); anIt != aCoinsideLines.end(); ++anIt) {
-      if(!(*anIt)->boolean(SketchPlugin_SketchEntity::AUXILIARY_ID())->value()) {
-        aNewLines.insert(*anIt);
+  // there is a check whether the feature contains a point and a linear edge or two point values
+  std::string aParamA = theArguments.front();
+  SessionPtr aMgr = ModelAPI_Session::get();
+  ModelAPI_ValidatorsFactory* aFactory = aMgr->validators();
+
+  FeaturePtr anAttributeFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(theAttribute->owner());
+  AttributeRefAttrPtr aRefAttr = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(theAttribute);
+  AttributeRefAttrPtr anOtherAttr = anAttributeFeature->data()->refattr(aParamA);
+
+  AttributeRefAttrPtr aRefAttrs[2] = {aRefAttr, anOtherAttr};
+  int aNbPoints = 0;
+  int aNbLines = 0;
+  for (int i = 0; i < 2; ++i) {
+    if (!aRefAttrs[i]->isObject())
+      ++aNbPoints;
+    else {
+      FeaturePtr aFeature = ModelAPI_Feature::feature(aRefAttrs[i]->object());
+      if (!aFeature) {
+        if (aNbPoints + aNbLines != 0)
+          return true;
+        else continue;
       }
+
+      if (aFeature->getKind() == SketchPlugin_Point::ID())
+        ++aNbPoints;
+      else if (aFeature->getKind() == SketchPlugin_Line::ID())
+        ++aNbLines;
     }
-    aCoinsideLines = aNewLines;
   }
 
-  if(aCoinsideLines.size() != 2) {
+  if (aNbPoints != 1 || aNbLines != 1) {
+    theError = "Middle point constraint allows points and lines only";
+    return false;
+  }
+  return true;
+}
+
+bool SketchPlugin_ArcTangentPointValidator::isValid(const AttributePtr& theAttribute,
+                                                    const std::list<std::string>& /*theArguments*/,
+                                                    std::string& theError) const
+{
+  if (theAttribute->attributeType() != ModelAPI_AttributeRefAttr::typeId()) {
+    theError = "The attribute with the " + theAttribute->attributeType() + " type is not processed";
+    return false;
+  }
+  AttributeRefAttrPtr aRefAttr = std::dynamic_pointer_cast<ModelAPI_AttributeRefAttr>(theAttribute);
+  AttributePtr anAttr = aRefAttr->attr();
+  if (!anAttr) {
+    theError = "The attribute " + theAttribute->id() + " should be a point";
     return false;
   }
 
-  // Check that lines not collinear
-  std::set<FeaturePtr>::iterator anIt = aCoinsideLines.begin();
-  FeaturePtr aFirstFeature = *anIt++;
-  FeaturePtr aSecondFeature = *anIt;
-  if(aFirstFeature->getKind() == SketchPlugin_Line::ID() && aSecondFeature->getKind() == SketchPlugin_Line::ID()) {
-    std::string aStartAttr = SketchPlugin_Line::START_ID();
-    std::string anEndAttr = SketchPlugin_Line::END_ID();
-    std::shared_ptr<GeomAPI_Pnt2d> aFirstStartPnt, aFirstEndPnt, aSecondStartPnt, aSecondEndPnt;
-    aFirstStartPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aFirstFeature->attribute(aStartAttr))->pnt();
-    aFirstEndPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aFirstFeature->attribute(anEndAttr))->pnt();
-    aSecondStartPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aSecondFeature->attribute(aStartAttr))->pnt();
-    aSecondEndPnt = std::dynamic_pointer_cast<GeomDataAPI_Point2D>(aSecondFeature->attribute(anEndAttr))->pnt();
-    double aCheck1 = abs((aFirstEndPnt->x() - aFirstStartPnt->x()) * (aSecondStartPnt->y() - aFirstStartPnt->y()) -
-      (aSecondStartPnt->x() - aFirstStartPnt->x()) * (aFirstEndPnt->y() - aFirstStartPnt->y()));
-    double aCheck2 = abs((aFirstEndPnt->x() - aFirstStartPnt->x()) * (aSecondEndPnt->y() - aFirstStartPnt->y()) -
-      (aSecondEndPnt->x() - aFirstStartPnt->x()) * (aFirstEndPnt->y() - aFirstStartPnt->y()));
-    if(aCheck1 < 1.e-7 && aCheck2 < 1.e-7) {
+  FeaturePtr anAttrFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(anAttr->owner());
+  const std::string& aFeatureType = anAttrFeature->getKind();
+  if (aFeatureType == SketchPlugin_Arc::ID()) {
+    // selected point should not be a center of arc
+    const std::string& aPntId = anAttr->id();
+    if (aPntId != SketchPlugin_Arc::START_ID() && aPntId != SketchPlugin_Arc::END_ID()) {
+      theError = "The attribute " + aPntId + " is not supported";
+      return false;
+    }
+  }
+  else if (aFeatureType == SketchPlugin_Line::ID()) {
+    // selected point should be bound point of line
+    const std::string& aPntId = anAttr->id();
+    if (aPntId != SketchPlugin_Line::START_ID() && aPntId != SketchPlugin_Line::END_ID()) {
+      theError = "The attribute " + aPntId + " is not supported";
       return false;
     }
   }
+  else {
+    theError = "Unable to build tangent arc on " + anAttrFeature->getKind();
+    return false;
+  }
 
   return true;
 }