diff --git a/src/Mod/Sketcher/App/SketchObject.h b/src/Mod/Sketcher/App/SketchObject.h
index c3386cabda..66050695a0 100644
--- a/src/Mod/Sketcher/App/SketchObject.h
+++ b/src/Mod/Sketcher/App/SketchObject.h
@@ -353,9 +353,23 @@ public:
     inline const std::vector<int> &getLastConflicting(void) const { return lastConflicting; }
     /// gets the redundant constraints of last solver execution
     inline const std::vector<int> &getLastRedundant(void) const { return lastRedundant; }
-    /// gets the solved sketch as a reference
-    inline Sketch &getSolvedSketch(void) {return solvedSketch;}
 
+public: /* Solver exposed interface */
+    /// gets the solved sketch as a reference
+    inline const Sketch &getSolvedSketch(void) const {return solvedSketch;}
+    /// enables/disables solver initial solution recalculation when moving point mode (useful for dragging)
+    inline void setRecalculateInitialSolutionWhileMovingPoint(bool recalculateInitialSolutionWhileMovingPoint)
+        {solvedSketch.setRecalculateInitialSolutionWhileMovingPoint(recalculateInitialSolutionWhileMovingPoint);}
+    /// Forwards a request for a temporary initMove to the solver using the current sketch state as a reference (enables dragging)
+    inline int initTemporaryMove(int geoId, PointPos pos, bool fine=true)
+        { return solvedSketch.initMove(geoId,pos,fine);}
+    /// Forwards a request for point or curve temporary movement to the solver using the current state as a reference (enables dragging)
+    inline int moveTemporaryPoint(int geoId, PointPos pos, Base::Vector3d toPoint, bool relative=false)
+        { return solvedSketch.movePoint(geoId, pos, toPoint, relative);}
+    inline void updateSolverExtension(int geoId, std::unique_ptr<Part::GeometryExtension> && ext)
+        { return solvedSketch.updateExtension(geoId, std::move(ext));}
+
+public:
     /// returns the geometric elements/vertex which the solver detects as having dependent parameters.
     /// these parameters relate to not fully constraint edges/vertices.
     void getGeometryWithDependentParameters(std::vector<std::pair<int,PointPos>>& geometrymap);
diff --git a/src/Mod/Sketcher/Gui/TaskSketcherSolverAdvanced.cpp b/src/Mod/Sketcher/Gui/TaskSketcherSolverAdvanced.cpp
index cf6769a11a..c5f6b4edb3 100644
--- a/src/Mod/Sketcher/Gui/TaskSketcherSolverAdvanced.cpp
+++ b/src/Mod/Sketcher/Gui/TaskSketcherSolverAdvanced.cpp
@@ -132,9 +132,12 @@ void TaskSketcherSolverAdvanced::updateDefaultMethodParameters(void)
             ui->lineEditSolverParam1->setText(QString::number(eps).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditSolverParam2->setText(QString::number(eps1).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditSolverParam3->setText(QString::number(tau).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
-            sketchView->getSketchObject()->getSolvedSketch().setLM_eps(eps);
-            sketchView->getSketchObject()->getSolvedSketch().setLM_eps1(eps1);
-            sketchView->getSketchObject()->getSolvedSketch().setLM_tau(tau);
+            // SketchObject has encapsulated write-access. The current use of const_cast just for configuration is
+            // deemed acceptable. Eventually this dialog should be rewritten to include only useful information and the configuration
+            // centralised in an individual configuration object, possibly compatible with several solvers (e.g. DeepSOIC's ConstraintSolver)
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_eps(eps);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_eps1(eps1);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_tau(tau);
             break;
         }
         case 2: // DogLeg
@@ -151,9 +154,9 @@ void TaskSketcherSolverAdvanced::updateDefaultMethodParameters(void)
             ui->lineEditSolverParam1->setText(QString::number(tolg).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditSolverParam2->setText(QString::number(tolx).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditSolverParam3->setText(QString::number(tolf).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolg(tolg);
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolf(tolf);
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolx(tolx);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolg(tolg);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolf(tolf);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolx(tolx);
             break;
         }
     }
@@ -198,9 +201,9 @@ void TaskSketcherSolverAdvanced::updateRedundantMethodParameters(void)
             ui->lineEditRedundantSolverParam1->setText(QString::number(eps).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditRedundantSolverParam2->setText(QString::number(eps1).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditRedundantSolverParam3->setText(QString::number(tau).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
-            sketchView->getSketchObject()->getSolvedSketch().setLM_epsRedundant(eps);
-            sketchView->getSketchObject()->getSolvedSketch().setLM_eps1Redundant(eps1);
-            sketchView->getSketchObject()->getSolvedSketch().setLM_tauRedundant(eps1);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_epsRedundant(eps);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_eps1Redundant(eps1);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_tauRedundant(eps1);
             break;
         }
         case 2: // DogLeg
@@ -217,9 +220,9 @@ void TaskSketcherSolverAdvanced::updateRedundantMethodParameters(void)
             ui->lineEditRedundantSolverParam1->setText(QString::number(tolg).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditRedundantSolverParam2->setText(QString::number(tolx).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
             ui->lineEditRedundantSolverParam3->setText(QString::number(tolf).remove(QString::fromLatin1("+").replace(QString::fromLatin1("e0"),QString::fromLatin1("E")).toUpper()));
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolgRedundant(tolg);
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolfRedundant(tolf);
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolxRedundant(tolx);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolgRedundant(tolg);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolfRedundant(tolf);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolxRedundant(tolx);
             break;
         }
     }
@@ -238,14 +241,14 @@ void TaskSketcherSolverAdvanced::on_lineEditSolverParam1_editingFinished()
     {
         case 1: // LM
         {
-            sketchView->getSketchObject()->getSolvedSketch().setLM_eps(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_eps(val);
             ui->lineEditSolverParam1->setEntryName("LM_eps");
             ui->lineEditSolverParam1->onSave();
             break;
         }
         case 2: // DogLeg
         {
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolg(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolg(val);
             ui->lineEditSolverParam1->setEntryName("DL_tolg");
             ui->lineEditSolverParam1->onSave();
             break;
@@ -266,14 +269,14 @@ void TaskSketcherSolverAdvanced::on_lineEditRedundantSolverParam1_editingFinishe
     {
         case 1: // LM
         {
-            sketchView->getSketchObject()->getSolvedSketch().setLM_epsRedundant(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_epsRedundant(val);
             ui->lineEditRedundantSolverParam1->setEntryName("Redundant_LM_eps");
             ui->lineEditRedundantSolverParam1->onSave();
             break;
         }
         case 2: // DogLeg
         {
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolgRedundant(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolgRedundant(val);
             ui->lineEditRedundantSolverParam1->setEntryName("Redundant_DL_tolg");
             ui->lineEditRedundantSolverParam1->onSave();
             break;
@@ -294,14 +297,14 @@ void TaskSketcherSolverAdvanced::on_lineEditSolverParam2_editingFinished()
     {
         case 1: // LM
         {
-            sketchView->getSketchObject()->getSolvedSketch().setLM_eps1(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_eps1(val);
             ui->lineEditSolverParam2->setEntryName("LM_eps1");
             ui->lineEditSolverParam2->onSave();
             break;
         }
         case 2: // DogLeg
         {
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolx(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolx(val);
             ui->lineEditSolverParam2->setEntryName("DL_tolx");
             ui->lineEditSolverParam2->onSave();
             break;
@@ -322,14 +325,14 @@ void TaskSketcherSolverAdvanced::on_lineEditRedundantSolverParam2_editingFinishe
     {
         case 1: // LM
         {
-            sketchView->getSketchObject()->getSolvedSketch().setLM_eps1Redundant(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_eps1Redundant(val);
             ui->lineEditRedundantSolverParam2->setEntryName("Redundant_LM_eps1");
             ui->lineEditRedundantSolverParam2->onSave();
             break;
         }
         case 2: // DogLeg
         {
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolxRedundant(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolxRedundant(val);
             ui->lineEditRedundantSolverParam2->setEntryName("Redundant_DL_tolx");
             ui->lineEditRedundantSolverParam2->onSave();
             break;
@@ -350,14 +353,14 @@ void TaskSketcherSolverAdvanced::on_lineEditSolverParam3_editingFinished()
     {
         case 1: // LM
         {
-            sketchView->getSketchObject()->getSolvedSketch().setLM_tau(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_tau(val);
             ui->lineEditSolverParam3->setEntryName("LM_tau");
             ui->lineEditSolverParam3->onSave();
             break;
         }
         case 2: // DogLeg
         {
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolf(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolf(val);
             ui->lineEditSolverParam3->setEntryName("DL_tolf");
             ui->lineEditSolverParam3->onSave();
             break;
@@ -378,14 +381,14 @@ void TaskSketcherSolverAdvanced::on_lineEditRedundantSolverParam3_editingFinishe
     {
         case 1: // LM
         {
-            sketchView->getSketchObject()->getSolvedSketch().setLM_tauRedundant(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setLM_tauRedundant(val);
             ui->lineEditRedundantSolverParam3->setEntryName("Redundant_LM_tau");
             ui->lineEditRedundantSolverParam3->onSave();
             break;
         }
         case 2: // DogLeg
         {
-            sketchView->getSketchObject()->getSolvedSketch().setDL_tolfRedundant(val);
+            const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDL_tolfRedundant(val);
             ui->lineEditRedundantSolverParam3->setEntryName("Redundant_DL_tolf");
             ui->lineEditRedundantSolverParam3->onSave();
             break;
@@ -396,32 +399,32 @@ void TaskSketcherSolverAdvanced::on_lineEditRedundantSolverParam3_editingFinishe
 void TaskSketcherSolverAdvanced::on_comboBoxDefaultSolver_currentIndexChanged(int index)
 {
     ui->comboBoxDefaultSolver->onSave();
-    sketchView->getSketchObject()->getSolvedSketch().defaultSolver=(GCS::Algorithm) index;
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).defaultSolver=(GCS::Algorithm) index;
     updateDefaultMethodParameters();
 }
 
 void TaskSketcherSolverAdvanced::on_comboBoxDogLegGaussStep_currentIndexChanged(int index)
 {
     ui->comboBoxDogLegGaussStep->onSave();
-    sketchView->getSketchObject()->getSolvedSketch().setDogLegGaussStep((GCS::DogLegGaussStep) index);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDogLegGaussStep((GCS::DogLegGaussStep) index);
     updateDefaultMethodParameters();
 }
 
 void TaskSketcherSolverAdvanced::on_spinBoxMaxIter_valueChanged(int i)
 {
     ui->spinBoxMaxIter->onSave();
-    sketchView->getSketchObject()->getSolvedSketch().setMaxIter(i);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setMaxIter(i);
 }
 
 void TaskSketcherSolverAdvanced::on_checkBoxSketchSizeMultiplier_stateChanged(int state)
 {
     if(state==Qt::Checked) {
         ui->checkBoxSketchSizeMultiplier->onSave();
-        sketchView->getSketchObject()->getSolvedSketch().setSketchSizeMultiplier(true);
+        const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setSketchSizeMultiplier(true);
     }
     else if (state==Qt::Unchecked) {
         ui->checkBoxSketchSizeMultiplier->onSave();
-        sketchView->getSketchObject()->getSolvedSketch().setSketchSizeMultiplier(false);
+        const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setSketchSizeMultiplier(false);
     }
 }
 
@@ -436,7 +439,7 @@ void TaskSketcherSolverAdvanced::on_lineEditQRPivotThreshold_editingFinished()
 
     ui->lineEditQRPivotThreshold->onSave();
 
-    sketchView->getSketchObject()->getSolvedSketch().setQRPivotThreshold(val);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setQRPivotThreshold(val);
 }
 
 void TaskSketcherSolverAdvanced::on_lineEditConvergence_editingFinished()
@@ -450,7 +453,7 @@ void TaskSketcherSolverAdvanced::on_lineEditConvergence_editingFinished()
 
     ui->lineEditConvergence->onSave();
 
-    sketchView->getSketchObject()->getSolvedSketch().setConvergence(val);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setConvergence(val);
 }
 
 void TaskSketcherSolverAdvanced::on_lineEditRedundantConvergence_editingFinished()
@@ -464,44 +467,44 @@ void TaskSketcherSolverAdvanced::on_lineEditRedundantConvergence_editingFinished
 
     ui->lineEditRedundantConvergence->onSave();
 
-    sketchView->getSketchObject()->getSolvedSketch().setConvergenceRedundant(val);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setConvergenceRedundant(val);
 }
 
 void TaskSketcherSolverAdvanced::on_comboBoxQRMethod_currentIndexChanged(int index)
 {
-    sketchView->getSketchObject()->getSolvedSketch().setQRAlgorithm((GCS::QRAlgorithm) index);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setQRAlgorithm((GCS::QRAlgorithm) index);
     ui->comboBoxQRMethod->onSave();
 }
 
 void TaskSketcherSolverAdvanced::on_comboBoxRedundantDefaultSolver_currentIndexChanged(int index)
 {
     ui->comboBoxRedundantDefaultSolver->onSave();
-    sketchView->getSketchObject()->getSolvedSketch().defaultSolverRedundant=(GCS::Algorithm) index;
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).defaultSolverRedundant=(GCS::Algorithm) index;
     updateRedundantMethodParameters();
 }
 
 void TaskSketcherSolverAdvanced::on_spinBoxRedundantSolverMaxIterations_valueChanged(int i)
 {
     ui->spinBoxRedundantSolverMaxIterations->onSave();
-    sketchView->getSketchObject()->getSolvedSketch().setMaxIterRedundant(i);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setMaxIterRedundant(i);
 }
 
 void TaskSketcherSolverAdvanced::on_checkBoxRedundantSketchSizeMultiplier_stateChanged(int state)
 {
     if(state==Qt::Checked) {
         ui->checkBoxRedundantSketchSizeMultiplier->onSave();
-        sketchView->getSketchObject()->getSolvedSketch().setSketchSizeMultiplierRedundant(true);
+        const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setSketchSizeMultiplierRedundant(true);
     }
     else if (state==Qt::Unchecked) {
         ui->checkBoxRedundantSketchSizeMultiplier->onSave();
-        sketchView->getSketchObject()->getSolvedSketch().setSketchSizeMultiplierRedundant(true);
+        const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setSketchSizeMultiplierRedundant(true);
     }
 }
 
 void TaskSketcherSolverAdvanced::on_comboBoxDebugMode_currentIndexChanged(int index)
 {
     ui->comboBoxDebugMode->onSave();
-    sketchView->getSketchObject()->getSolvedSketch().setDebugMode((GCS::DebugMode) index);
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDebugMode((GCS::DebugMode) index);
 }
 
 void TaskSketcherSolverAdvanced::on_pushButtonSolve_clicked(bool checked/* = false*/)
@@ -560,18 +563,18 @@ void TaskSketcherSolverAdvanced::on_pushButtonDefaults_clicked(bool checked/* =
 
 void TaskSketcherSolverAdvanced::updateSketchObject(void)
 {
-    sketchView->getSketchObject()->getSolvedSketch().setDebugMode((GCS::DebugMode) ui->comboBoxDebugMode->currentIndex());
-    sketchView->getSketchObject()->getSolvedSketch().setSketchSizeMultiplierRedundant(ui->checkBoxRedundantSketchSizeMultiplier->isChecked());
-    sketchView->getSketchObject()->getSolvedSketch().setMaxIterRedundant(ui->spinBoxRedundantSolverMaxIterations->value());
-    sketchView->getSketchObject()->getSolvedSketch().defaultSolverRedundant=(GCS::Algorithm) ui->comboBoxRedundantDefaultSolver->currentIndex();
-    sketchView->getSketchObject()->getSolvedSketch().setQRAlgorithm((GCS::QRAlgorithm) ui->comboBoxQRMethod->currentIndex());
-    sketchView->getSketchObject()->getSolvedSketch().setQRPivotThreshold(ui->lineEditQRPivotThreshold->text().toDouble());
-    sketchView->getSketchObject()->getSolvedSketch().setConvergenceRedundant(ui->lineEditRedundantConvergence->text().toDouble());
-    sketchView->getSketchObject()->getSolvedSketch().setConvergence(ui->lineEditConvergence->text().toDouble());
-    sketchView->getSketchObject()->getSolvedSketch().setSketchSizeMultiplier(ui->checkBoxSketchSizeMultiplier->isChecked());
-    sketchView->getSketchObject()->getSolvedSketch().setMaxIter(ui->spinBoxMaxIter->value());
-    sketchView->getSketchObject()->getSolvedSketch().defaultSolver=(GCS::Algorithm) ui->comboBoxDefaultSolver->currentIndex();
-    sketchView->getSketchObject()->getSolvedSketch().setDogLegGaussStep((GCS::DogLegGaussStep) ui->comboBoxDogLegGaussStep->currentIndex());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDebugMode((GCS::DebugMode) ui->comboBoxDebugMode->currentIndex());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setSketchSizeMultiplierRedundant(ui->checkBoxRedundantSketchSizeMultiplier->isChecked());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setMaxIterRedundant(ui->spinBoxRedundantSolverMaxIterations->value());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).defaultSolverRedundant=(GCS::Algorithm) ui->comboBoxRedundantDefaultSolver->currentIndex();
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setQRAlgorithm((GCS::QRAlgorithm) ui->comboBoxQRMethod->currentIndex());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setQRPivotThreshold(ui->lineEditQRPivotThreshold->text().toDouble());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setConvergenceRedundant(ui->lineEditRedundantConvergence->text().toDouble());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setConvergence(ui->lineEditConvergence->text().toDouble());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setSketchSizeMultiplier(ui->checkBoxSketchSizeMultiplier->isChecked());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setMaxIter(ui->spinBoxMaxIter->value());
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).defaultSolver=(GCS::Algorithm) ui->comboBoxDefaultSolver->currentIndex();
+    const_cast<Sketcher::Sketch &>(sketchView->getSketchObject()->getSolvedSketch()).setDogLegGaussStep((GCS::DogLegGaussStep) ui->comboBoxDogLegGaussStep->currentIndex());
 
     updateDefaultMethodParameters();
     updateRedundantMethodParameters();
diff --git a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
index 1abe2c1608..1b0c49080e 100644
--- a/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
+++ b/src/Mod/Sketcher/Gui/ViewProviderSketch.cpp
@@ -189,7 +189,7 @@ struct EditData {
     MarkerSize(7),
     blockedPreselection(false),
     FullyConstrained(false),
-    //ActSketch(0), // if you are wondering, it went to SketchObject, accessible via getSketchObject()->getSolvedSketch()
+    //ActSketch(0), // if you are wondering, it went to SketchObject, accessible via getSolvedSketch() and via SketchObject interface as appropriate
     EditRoot(0),
     PointsMaterials(0),
     CurvesMaterials(0),
@@ -1139,7 +1139,7 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
             }
             return false;
         case STATUS_SELECT_Point:
-            if (!getSketchObject()->getSolvedSketch().hasConflicts() &&
+            if (!getSolvedSketch().hasConflicts() &&
                 edit->PreselectPoint != -1 && edit->DragPoint != edit->PreselectPoint) {
                 Mode = STATUS_SKETCH_DragPoint;
                 edit->DragPoint = edit->PreselectPoint;
@@ -1147,7 +1147,7 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
                 Sketcher::PointPos PosId;
                 getSketchObject()->getGeoVertexIndex(edit->DragPoint, GeoId, PosId);
                 if (GeoId != Sketcher::Constraint::GeoUndef && PosId != Sketcher::none) {
-                    getSketchObject()->getSolvedSketch().initMove(GeoId, PosId, false);
+                    getSketchObject()->initTemporaryMove(GeoId, PosId, false);
                     relative = false;
                     xInit = 0;
                     yInit = 0;
@@ -1161,7 +1161,7 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
             edit->PreselectConstraintSet.clear();
             return true;
         case STATUS_SELECT_Edge:
-            if (!getSketchObject()->getSolvedSketch().hasConflicts() &&
+            if (!getSolvedSketch().hasConflicts() &&
                 edit->PreselectCurve != -1 && edit->DragCurve != edit->PreselectCurve) {
                 Mode = STATUS_SKETCH_DragCurve;
                 edit->DragCurve = edit->PreselectCurve;
@@ -1183,7 +1183,7 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
 
                         // The B-Spline is constrained to be non-rational (equal weights), moving produces a bad effect
                         // because OCCT will normalize the values of the weights.
-                        auto grp = getSketchObject()->getSolvedSketch().getDependencyGroup(edit->DragCurve, Sketcher::none);
+                        auto grp = getSolvedSketch().getDependencyGroup(edit->DragCurve, Sketcher::none);
 
                         int bsplinegeoid = -1;
 
@@ -1231,7 +1231,7 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
 
                 }
 
-                getSketchObject()->getSolvedSketch().initMove(edit->DragCurve, Sketcher::none, false);
+                getSketchObject()->initTemporaryMove(edit->DragCurve, Sketcher::none, false);
 
                 if (geo->getTypeId() == Part::GeomLineSegment::getClassTypeId() ||
                     geo->getTypeId() == Part::GeomBSplineCurve::getClassTypeId()) {
@@ -1273,12 +1273,12 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
                 getSketchObject()->getGeoVertexIndex(edit->DragPoint, GeoId, PosId);
                 Base::Vector3d vec(x,y,0);
                 if (GeoId != Sketcher::Constraint::GeoUndef && PosId != Sketcher::none) {
-                    if (getSketchObject()->getSolvedSketch().movePoint(GeoId, PosId, vec, false) == 0) {
+                    if (getSketchObject()->moveTemporaryPoint(GeoId, PosId, vec, false) == 0) {
                         setPositionText(Base::Vector2d(x,y));
                         draw(true,false);
-                        signalSolved(QString::fromLatin1("Solved in %1 sec").arg(getSketchObject()->getSolvedSketch().getSolveTime()));
+                        signalSolved(QString::fromLatin1("Solved in %1 sec").arg(getSolvedSketch().getSolveTime()));
                     } else {
-                        signalSolved(QString::fromLatin1("Unsolved (%1 sec)").arg(getSketchObject()->getSolvedSketch().getSolveTime()));
+                        signalSolved(QString::fromLatin1("Unsolved (%1 sec)").arg(getSolvedSketch().getSolveTime()));
                         //Base::Console().Log("Error solving:%d\n",ret);
                     }
                 }
@@ -1314,12 +1314,12 @@ bool ViewProviderSketch::mouseMove(const SbVec2s &cursorPos, Gui::View3DInventor
                     vec = center + dir / scalefactor;
                 }
 
-                if (getSketchObject()->getSolvedSketch().movePoint(edit->DragCurve, Sketcher::none, vec, relative) == 0) {
+                if (getSketchObject()->moveTemporaryPoint(edit->DragCurve, Sketcher::none, vec, relative) == 0) {
                     setPositionText(Base::Vector2d(x,y));
                     draw(true,false);
-                    signalSolved(QString::fromLatin1("Solved in %1 sec").arg(getSketchObject()->getSolvedSketch().getSolveTime()));
+                    signalSolved(QString::fromLatin1("Solved in %1 sec").arg(getSolvedSketch().getSolveTime()));
                 } else {
-                    signalSolved(QString::fromLatin1("Unsolved (%1 sec)").arg(getSketchObject()->getSolvedSketch().getSolveTime()));
+                    signalSolved(QString::fromLatin1("Unsolved (%1 sec)").arg(getSolvedSketch().getSolveTime()));
                 }
             }
             return true;
@@ -1380,7 +1380,7 @@ void ViewProviderSketch::moveConstraint(int constNum, const Base::Vector2d &toPo
 #endif
 
     // with memory allocation
-    const std::vector<Part::Geometry *> geomlist = getSketchObject()->getSolvedSketch().extractGeometry(true, true);
+    const std::vector<Part::Geometry *> geomlist = getSolvedSketch().extractGeometry(true, true);
 
 #ifdef _DEBUG
     assert(int(geomlist.size()) == extGeoCount + intGeoCount);
@@ -1393,10 +1393,10 @@ void ViewProviderSketch::moveConstraint(int constNum, const Base::Vector2d &toPo
 
         Base::Vector3d p1(0.,0.,0.), p2(0.,0.,0.);
         if (Constr->SecondPos != Sketcher::none) { // point to point distance
-            p1 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
-            p2 = getSketchObject()->getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
+            p1 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+            p2 = getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
         } else if (Constr->Second != Constraint::GeoUndef) { // point to line distance
-            p1 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+            p1 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
             const Part::Geometry *geo = GeoById(geomlist, Constr->Second);
             if (geo->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
                 const Part::GeomLineSegment *lineSeg = static_cast<const Part::GeomLineSegment *>(geo);
@@ -1408,7 +1408,7 @@ void ViewProviderSketch::moveConstraint(int constNum, const Base::Vector2d &toPo
             } else
                 return;
         } else if (Constr->FirstPos != Sketcher::none) {
-            p2 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+            p2 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
         } else if (Constr->First != Constraint::GeoUndef) {
             const Part::Geometry *geo = GeoById(geomlist, Constr->First);
             if (geo->getTypeId() == Part::GeomLineSegment::getClassTypeId()) {
@@ -1534,11 +1534,11 @@ void ViewProviderSketch::moveConstraint(int constNum, const Base::Vector2d &toPo
                     factor = factor * Base::sgn<double>((dir1+dir2) * vec);
                 }
             } else {//angle-via-point
-                Base::Vector3d p = getSketchObject()->getSolvedSketch().getPoint(Constr->Third, Constr->ThirdPos);
+                Base::Vector3d p = getSolvedSketch().getPoint(Constr->Third, Constr->ThirdPos);
                 p0 = Base::Vector3d(p.x, p.y, 0);
-                dir1 = getSketchObject()->getSolvedSketch().calculateNormalAtPoint(Constr->First, p.x, p.y);
+                dir1 = getSolvedSketch().calculateNormalAtPoint(Constr->First, p.x, p.y);
                 dir1.RotateZ(-M_PI/2);//convert to vector of tangency by rotating
-                dir2 = getSketchObject()->getSolvedSketch().calculateNormalAtPoint(Constr->Second, p.x, p.y);
+                dir2 = getSolvedSketch().calculateNormalAtPoint(Constr->Second, p.x, p.y);
                 dir2.RotateZ(-M_PI/2);
 
                 Base::Vector3d vec = Base::Vector3d(toPos.x, toPos.y, 0) - p0;
@@ -3032,7 +3032,7 @@ void ViewProviderSketch::updateColor(void)
             } else if (type == Sketcher::Coincident) {
                 auto selectpoint = [this, pcolor, PtNum](int geoid, Sketcher::PointPos pos){
                     if(geoid >= 0) {
-                        int index = getSketchObject()->getSolvedSketch().getPointId(geoid, pos) + 1;
+                        int index = getSolvedSketch().getPointId(geoid, pos) + 1;
                         if (index >= 0 && index < PtNum)
                             pcolor[index] = SelectColor;
                     }
@@ -3060,7 +3060,7 @@ void ViewProviderSketch::updateColor(void)
                     case EllipseFocus1:
                     case EllipseFocus2:
                     {
-                        int index = getSketchObject()->getSolvedSketch().getPointId(constraint->First, constraint->FirstPos) + 1;
+                        int index = getSolvedSketch().getPointId(constraint->First, constraint->FirstPos) + 1;
                         if (index >= 0 && index < PtNum) pcolor[index] = SelectColor;
                     }
                     break;
@@ -3760,7 +3760,7 @@ void ViewProviderSketch::draw(bool temp /*=false*/, bool rebuildinformationlayer
     const std::vector<Part::Geometry *> *geomlist;
     std::vector<Part::Geometry *> tempGeo;
     if (temp)
-        tempGeo = getSketchObject()->getSolvedSketch().extractGeometry(true, true); // with memory allocation
+        tempGeo = getSolvedSketch().extractGeometry(true, true); // with memory allocation
     else
         tempGeo = getSketchObject()->getCompleteGeometry(); // without memory allocation
     geomlist = &tempGeo;
@@ -3880,7 +3880,7 @@ void ViewProviderSketch::draw(bool temp /*=false*/, bool rebuildinformationlayer
                                 auto vpext = std::make_unique<SketcherGui::ViewProviderSketchGeometryExtension>();
                                 vpext->setRepresentationFactor(scalefactor);
 
-                                getSketchObject()->getSolvedSketch().updateExtension(GeoId, std::move(vpext));
+                                getSketchObject()->updateSolverExtension(GeoId, std::move(vpext));
                             }
 
                             if(!circle->hasExtension(SketcherGui::ViewProviderSketchGeometryExtension::getClassTypeId()))
@@ -4881,12 +4881,12 @@ Restart:
                             Base::Vector3d midpos2, dir2, norm2;
 
                             if (temp)
-                                midpos1 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+                                midpos1 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
                             else
                                 midpos1 = getSketchObject()->getPoint(Constr->First, Constr->FirstPos);
 
                             if (temp)
-                                midpos2 = getSketchObject()->getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
+                                midpos2 = getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
                             else
                                 midpos2 = getSketchObject()->getPoint(Constr->Second, Constr->SecondPos);
 
@@ -4938,11 +4938,11 @@ Restart:
                                 assert(0);//no point found!
                             } while (false);
                             if (temp)
-                                midpos1 = getSketchObject()->getSolvedSketch().getPoint(ptGeoId, ptPosId);
+                                midpos1 = getSolvedSketch().getPoint(ptGeoId, ptPosId);
                             else
                                 midpos1 = getSketchObject()->getPoint(ptGeoId, ptPosId);
 
-                            norm1 = getSketchObject()->getSolvedSketch().calculateNormalAtPoint(Constr->Second, midpos1.x, midpos1.y);
+                            norm1 = getSolvedSketch().calculateNormalAtPoint(Constr->Second, midpos1.x, midpos1.y);
                             norm1.Normalize();
                             dir1 = norm1; dir1.RotateZ(-M_PI/2.0);
 
@@ -5206,15 +5206,15 @@ Restart:
                         Base::Vector3d pnt1(0.,0.,0.), pnt2(0.,0.,0.);
                         if (Constr->SecondPos != Sketcher::none) { // point to point distance
                             if (temp) {
-                                pnt1 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
-                                pnt2 = getSketchObject()->getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
+                                pnt1 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+                                pnt2 = getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
                             } else {
                                 pnt1 = getSketchObject()->getPoint(Constr->First, Constr->FirstPos);
                                 pnt2 = getSketchObject()->getPoint(Constr->Second, Constr->SecondPos);
                             }
                         } else if (Constr->Second != Constraint::GeoUndef) { // point to line distance
                             if (temp) {
-                                pnt1 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+                                pnt1 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
                             } else {
                                 pnt1 = getSketchObject()->getPoint(Constr->First, Constr->FirstPos);
                             }
@@ -5230,7 +5230,7 @@ Restart:
                                 break;
                         } else if (Constr->FirstPos != Sketcher::none) {
                             if (temp) {
-                                pnt2 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+                                pnt2 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
                             } else {
                                 pnt2 = getSketchObject()->getPoint(Constr->First, Constr->FirstPos);
                             }
@@ -5301,9 +5301,9 @@ Restart:
                                 if (ptPosId != Sketcher::none) break;
                                 assert(0);//no point found!
                             } while (false);
-                            pos = getSketchObject()->getSolvedSketch().getPoint(ptGeoId, ptPosId);
+                            pos = getSolvedSketch().getPoint(ptGeoId, ptPosId);
 
-                            Base::Vector3d norm = getSketchObject()->getSolvedSketch().calculateNormalAtPoint(Constr->Second, pos.x, pos.y);
+                            Base::Vector3d norm = getSolvedSketch().calculateNormalAtPoint(Constr->Second, pos.x, pos.y);
                             norm.Normalize();
                             Base::Vector3d dir = norm; dir.RotateZ(-M_PI/2.0);
 
@@ -5429,8 +5429,8 @@ Restart:
                         assert(Constr->First >= -extGeoCount && Constr->First < intGeoCount);
                         assert(Constr->Second >= -extGeoCount && Constr->Second < intGeoCount);
 
-                        Base::Vector3d pnt1 = getSketchObject()->getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
-                        Base::Vector3d pnt2 = getSketchObject()->getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
+                        Base::Vector3d pnt1 = getSolvedSketch().getPoint(Constr->First, Constr->FirstPos);
+                        Base::Vector3d pnt2 = getSolvedSketch().getPoint(Constr->Second, Constr->SecondPos);
 
                         SbVec3f p1(pnt1.x,pnt1.y,zConstr);
                         SbVec3f p2(pnt2.x,pnt2.y,zConstr);
@@ -5513,11 +5513,11 @@ Restart:
                                 startangle = atan2(dir1.y,dir1.x);
                             }
                             else {//angle-via-point
-                                Base::Vector3d p = getSketchObject()->getSolvedSketch().getPoint(Constr->Third, Constr->ThirdPos);
+                                Base::Vector3d p = getSolvedSketch().getPoint(Constr->Third, Constr->ThirdPos);
                                 p0 = SbVec3f(p.x, p.y, 0);
-                                dir1 = getSketchObject()->getSolvedSketch().calculateNormalAtPoint(Constr->First, p.x, p.y);
+                                dir1 = getSolvedSketch().calculateNormalAtPoint(Constr->First, p.x, p.y);
                                 dir1.RotateZ(-M_PI/2);//convert to vector of tangency by rotating
-                                dir2 = getSketchObject()->getSolvedSketch().calculateNormalAtPoint(Constr->Second, p.x, p.y);
+                                dir2 = getSolvedSketch().calculateNormalAtPoint(Constr->Second, p.x, p.y);
                                 dir2.RotateZ(-M_PI/2);
 
                                 startangle = atan2(dir1.y,dir1.x);
@@ -6001,7 +6001,7 @@ void ViewProviderSketch::updateData(const App::Property *prop)
         UpdateSolverInformation(); // just update the solver window with the last SketchObject solving information
 
         if(getSketchObject()->getExternalGeometryCount()+getSketchObject()->getHighestCurveIndex() + 1 ==
-            getSketchObject()->getSolvedSketch().getGeometrySize()) {
+            getSolvedSketch().getGeometrySize()) {
             Gui::MDIView *mdi = Gui::Application::Instance->editDocument()->getActiveView();
             if (mdi->isDerivedFrom(Gui::View3DInventor::getClassTypeId()))
                 draw(false,true);
@@ -6255,8 +6255,7 @@ bool ViewProviderSketch::setEdit(int ModNum)
     // Enable solver initial solution update while dragging.
     ParameterGrp::handle hGrp2 = App::GetApplication().GetParameterGroupByPath("User parameter:BaseApp/Preferences/Mod/Sketcher");
 
-    getSketchObject()->getSolvedSketch().setRecalculateInitialSolutionWhileMovingPoint(hGrp2->GetBool("RecalculateInitialSolutionWhileDragging",true));
-
+    getSketchObject()->setRecalculateInitialSolutionWhileMovingPoint(hGrp2->GetBool("RecalculateInitialSolutionWhileDragging",true));
 
     // intercept del key press from main app
     listener = new ShortcutListener(this);
@@ -6340,7 +6339,7 @@ void ViewProviderSketch::UpdateSolverInformation()
         if (getSketchObject()->getLastSolverStatus() == 0) {
             if (dofs == 0) {
                 // color the sketch as fully constrained if it has geometry (other than the axes)
-                if(getSketchObject()->getSolvedSketch().getGeometrySize()>2)
+                if(getSolvedSketch().getGeometrySize()>2)
                     edit->FullyConstrained = true;
 
                 if (!hasRedundancies) {
@@ -6826,6 +6825,11 @@ Sketcher::SketchObject *ViewProviderSketch::getSketchObject(void) const
     return dynamic_cast<Sketcher::SketchObject *>(pcObject);
 }
 
+const Sketcher::Sketch &ViewProviderSketch::getSolvedSketch(void) const
+{
+    return const_cast<const Sketcher::SketchObject *>(getSketchObject())->getSolvedSketch();
+}
+
 void ViewProviderSketch::deleteSelected()
 {
     std::vector<Gui::SelectionObject> selection;
diff --git a/src/Mod/Sketcher/Gui/ViewProviderSketch.h b/src/Mod/Sketcher/Gui/ViewProviderSketch.h
index ab64445c54..6d42806956 100644
--- a/src/Mod/Sketcher/Gui/ViewProviderSketch.h
+++ b/src/Mod/Sketcher/Gui/ViewProviderSketch.h
@@ -194,6 +194,18 @@ public:
     /// get the pointer to the sketch document object
     Sketcher::SketchObject *getSketchObject(void) const;
 
+    /** returns a const reference to the last solved sketch object. It guarantees that
+     *  the solver object does not lose synchronisation with the SketchObject properties.
+     *
+     * NOTE: Operations requiring write access to the solver must be done via SketchObject
+     * interface. See for example functions:
+     * -> inline void setRecalculateInitialSolutionWhileMovingPoint(bool recalculateInitialSolutionWhileMovingPoint)
+     * -> inline int initTemporaryMove(int geoId, PointPos pos, bool fine=true)
+     * -> inline int moveTemporaryPoint(int geoId, PointPos pos, Base::Vector3d toPoint, bool relative=false)
+     * -> inline void updateSolverExtension(int geoId, std::unique_ptr<Part::GeometryExtension> && ext)
+     */
+    const Sketcher::Sketch &getSolvedSketch(void) const;
+
     /// snap points x,y (mouse coordinates) onto grid if enabled
     void snapToGrid(double &x, double &y);