From ce644b8305310f2f22ca46bf768ac96822a77dd2 Mon Sep 17 00:00:00 2001
From: Paul Baksic <paul.baksic@outlook.fr>
Date: Mon, 1 Dec 2025 11:36:47 +0100
Subject: [PATCH 1/4] Rename C++ symbols

---
 .../BlockGaussSeidelConstraintSolver.cpp      | 294 ++++++++++++++++++
 .../solver/BlockGaussSeidelConstraintSolver.h |  40 +++
 2 files changed, 334 insertions(+)
 create mode 100644 Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.cpp
 create mode 100644 Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h

diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.cpp b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.cpp
new file mode 100644
index 00000000000..590998bd3ea
--- /dev/null
+++ b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.cpp
@@ -0,0 +1,294 @@
+/******************************************************************************
+*                 SOFA, Simulation Open-Framework Architecture                *
+*                    (c) 2006 INRIA, USTL, UJF, CNRS, MGH                     *
+*                                                                             *
+* This program 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 program 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 program. If not, see <http://www.gnu.org/licenses/>.        *
+*******************************************************************************
+* Authors: The SOFA Team and external contributors (see Authors.txt)          *
+*                                                                             *
+* Contact information: contact@sofa-framework.org                             *
+******************************************************************************/
+
+#include <sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h>
+#include <sofa/component/constraint/lagrangian/solver/GenericConstraintSolver.h>
+#include <sofa/helper/AdvancedTimer.h>
+#include <sofa/helper/ScopedAdvancedTimer.h>
+#include <sofa/core/ObjectFactory.h>
+
+namespace sofa::component::constraint::lagrangian::solver
+{
+
+
+void BlockGaussSeidelConstraintSolver::doSolve( GenericConstraintProblem * problem ,SReal timeout)
+{
+    SCOPED_TIMER_VARNAME(gaussSeidelTimer, "ConstraintsGaussSeidel");
+
+
+
+    const int dimension = problem->getDimension();
+
+    if(!dimension)
+    {
+        problem->currentError = 0.0;
+        problem->currentIterations = 0;
+        return;
+    }
+
+    const SReal t0 = (SReal)sofa::helper::system::thread::CTime::getTime() ;
+    const SReal timeScale = 1.0 / (SReal)sofa::helper::system::thread::CTime::getTicksPerSec();
+
+
+    SReal *dfree = problem->getDfree();
+    SReal *force = problem->getF();
+    SReal **w = problem->getW();
+    SReal tol = problem->tolerance;
+    SReal *d = problem->_d.ptr();
+
+    SReal error=0.0;
+    bool convergence = false;
+    sofa::type::vector<SReal> tempForces;
+
+    if(problem->sor != 1.0)
+    {
+        tempForces.resize(dimension);
+    }
+
+    if(problem->scaleTolerance && !problem->allVerified)
+    {
+        tol *= dimension;
+    }
+
+    for(int i=0; i<dimension; )
+    {
+        if(!problem->constraintsResolutions[i])
+        {
+            msg_error()<< "Bad size of constraintsResolutions in GenericConstraintSolver" ;
+            break;
+        }
+        problem->constraintsResolutions[i]->init(i, w, force);
+        i += problem->constraintsResolutions[i]->getNbLines();
+    }
+
+    bool showGraphs = false;
+    sofa::type::vector<SReal>* graph_residuals = nullptr;
+    std::map < std::string, sofa::type::vector<SReal> > *graph_forces = nullptr, *graph_violations = nullptr;
+
+    showGraphs = d_computeGraphs.getValue();
+
+    if(showGraphs)
+    {
+        graph_forces = d_graphForces.beginEdit();
+        graph_forces->clear();
+
+        graph_violations = d_graphViolations.beginEdit();
+        graph_violations->clear();
+
+        graph_residuals = &(*d_graphErrors.beginEdit())["Error"];
+        graph_residuals->clear();
+    }
+
+    sofa::type::vector<SReal> tabErrors(dimension);
+
+    int iterCount = 0;
+
+
+    for(int i=0; i<problem->maxIterations; i++)
+    {
+        iterCount ++;
+        bool constraintsAreVerified = true;
+
+
+        if(problem->sor != 1.0)
+        {
+            std::copy_n(force, dimension, tempForces.begin());
+        }
+
+        error=0.0;
+
+        gaussSeidel_increment(true, dfree, force, w, tol, d, dimension, constraintsAreVerified, error, problem->constraintsResolutions, tabErrors);
+
+        if(showGraphs)
+        {
+            for(int j=0; j<dimension; j++)
+            {
+                std::ostringstream oss;
+                oss << "f" << j;
+
+                sofa::type::vector<SReal>& graph_force = (*graph_forces)[oss.str()];
+                graph_force.push_back(force[j]);
+
+                sofa::type::vector<SReal>& graph_violation = (*graph_violations)[oss.str()];
+                graph_violation.push_back(d[j]);
+            }
+
+            graph_residuals->push_back(error);
+        }
+
+        if(problem->sor != 1.0)
+        {
+            for(int j=0; j<dimension; j++)
+            {
+                force[j] = problem->sor * force[j] + (1-problem->sor) * tempForces[j];
+            }
+        }
+
+        const SReal t1 = (SReal)sofa::helper::system::thread::CTime::getTime();
+        const SReal dt = (t1 - t0)*timeScale;
+
+        if(timeout && dt > timeout)
+        {
+
+            msg_info() <<  "TimeOut" ;
+
+            problem->currentError = error;
+            problem->currentIterations = i+1;
+            return;
+        }
+        else if(problem->allVerified)
+        {
+            if(constraintsAreVerified)
+            {
+                convergence = true;
+                break;
+            }
+        }
+        else if(error < tol) // do not stop at the first iteration (that is used for initial guess computation)
+        {
+            convergence = true;
+            break;
+        }
+    }
+
+    sofa::helper::AdvancedTimer::valSet("GS iterations", problem->currentIterations);
+
+    problem->result_output(this, force, error, iterCount, convergence);
+
+    if(showGraphs)
+    {
+        d_graphErrors.endEdit();
+
+        sofa::type::vector<SReal>& graph_constraints = (*d_graphConstraints.beginEdit())["Constraints"];
+        graph_constraints.clear();
+
+        for(int j=0; j<dimension; )
+        {
+            const unsigned int nbDofs = problem->constraintsResolutions[j]->getNbLines();
+
+            if(tabErrors[j])
+                graph_constraints.push_back(tabErrors[j]);
+            else if(problem->constraintsResolutions[j]->getTolerance())
+                graph_constraints.push_back(problem->constraintsResolutions[j]->getTolerance());
+            else
+                graph_constraints.push_back(tol);
+
+            j += nbDofs;
+        }
+        d_graphConstraints.endEdit();
+
+        d_graphForces.endEdit();
+    }
+}
+
+void BlockGaussSeidelConstraintSolver::gaussSeidel_increment(bool measureError, SReal *dfree, SReal *force, SReal **w, SReal tol, SReal *d, int dim, bool& constraintsAreVerified, SReal& error, std::vector<core::behavior::ConstraintResolution*>& constraintCorrections, sofa::type::vector<SReal>& tabErrors) const
+{
+    for(int j=0; j<dim; ) // increment of j realized at the end of the loop
+    {
+        assert(j < constraintCorrections.size());
+        assert(constraintCorrections[j] != nullptr);
+
+        //1. nbLines provide the dimension of the constraint
+        const unsigned int nb = constraintCorrections[j]->getNbLines();
+
+        //2. for each line we compute the actual value of d
+        //   (a)d is set to dfree
+
+        std::vector<SReal> errF(&force[j], &force[j+nb]);
+        std::copy_n(&dfree[j], nb, &d[j]);
+
+        //   (b) contribution of forces are added to d     => TODO => optimization (no computation when force= 0 !!)
+        for(int k=0; k<dim; k++)
+        {
+            for(unsigned int l=0; l<nb; l++)
+            {
+                d[j+l] += w[j+l][k] * force[k];
+            }
+        }
+
+        //3. the specific resolution of the constraint(s) is called
+        constraintCorrections[j]->resolution(j, w, d, force, dfree);
+
+        //4. the error is measured (displacement due to the new resolution (i.e. due to the new force))
+        if(measureError)
+        {
+            SReal contraintError = 0.0;
+            if(nb > 1)
+            {
+                for(unsigned int l=0; l<nb; l++)
+                {
+                    SReal lineError = 0.0;
+                    for (unsigned int m=0; m<nb; m++)
+                    {
+                        const SReal dofError = w[j+l][j+m] * (force[j+m] - errF[m]);
+                        lineError += dofError * dofError;
+                    }
+                    lineError = sqrt(lineError);
+                    if(lineError > tol)
+                    {
+                        constraintsAreVerified = false;
+                    }
+
+                    contraintError += lineError;
+                }
+            }
+            else
+            {
+                contraintError = fabs(w[j][j] * (force[j] - errF[0]));
+                if(contraintError > tol)
+                {
+                    constraintsAreVerified = false;
+                }
+            }
+
+            const bool givenTolerance = (bool)constraintCorrections[j]->getTolerance();
+
+            if(givenTolerance)
+            {
+                if(contraintError > constraintCorrections[j]->getTolerance())
+                {
+                    constraintsAreVerified = false;
+                }
+                contraintError *= tol / constraintCorrections[j]->getTolerance();
+            }
+
+            error += contraintError;
+            tabErrors[j] = contraintError;
+        }
+        else
+        {
+            constraintsAreVerified = true;
+        }
+
+        j += nb;
+    }
+}
+
+
+void registerBlockGaussSeidelConstraintSolver(sofa::core::ObjectFactory* factory)
+{
+    factory->registerObjects(core::ObjectRegistrationData("A Constraint Solver using the Linear Complementarity Problem formulation to solve Constraint based components using a Block Gauss-Seidel iterative method")
+        .add< BlockGaussSeidelConstraintSolver >());
+}
+
+
+}
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h
new file mode 100644
index 00000000000..91ca8a6be5d
--- /dev/null
+++ b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h
@@ -0,0 +1,40 @@
+/******************************************************************************
+*                 SOFA, Simulation Open-Framework Architecture                *
+*                    (c) 2006 INRIA, USTL, UJF, CNRS, MGH                     *
+*                                                                             *
+* This program 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 program 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 program. If not, see <http://www.gnu.org/licenses/>.        *
+*******************************************************************************
+* Authors: The SOFA Team and external contributors (see Authors.txt)          *
+*                                                                             *
+* Contact information: contact@sofa-framework.org                             *
+******************************************************************************/
+#pragma once
+
+#include <sofa/component/constraint/lagrangian/solver/BuiltConstraintSolver.h>
+#include <sofa/core/behavior/ConstraintResolution.h>
+
+namespace sofa::component::constraint::lagrangian::solver
+{
+class SOFA_COMPONENT_CONSTRAINT_LAGRANGIAN_SOLVER_API BlockGaussSeidelConstraintSolver : public BuiltConstraintSolver
+{
+public:
+    SOFA_CLASS(BlockGaussSeidelConstraintSolver, BuiltConstraintSolver);
+
+protected:
+    virtual void doSolve(GenericConstraintProblem * problem , SReal timeout = 0.0) override;
+
+    void gaussSeidel_increment(bool measureError, SReal *dfree, SReal *force, SReal **w, SReal tol, SReal *d, int dim, bool& constraintsAreVerified, SReal& error, std::vector<core::behavior::ConstraintResolution*>& constraintCorrections, sofa::type::vector<SReal>& tabErrors) const;
+
+};
+}
\ No newline at end of file

From d67e64cd456267c67ee852f72b0bd47952501824 Mon Sep 17 00:00:00 2001
From: Paul Baksic <paul.baksic@outlook.fr>
Date: Mon, 1 Dec 2025 11:37:51 +0100
Subject: [PATCH 2/4] Report change in C++ files

---
 .../animationloop/FreeMotionAnimationLoop.cpp |   8 +-
 .../BilateralInteractionConstraint.scn        |   2 +-
 .../Lagrangian/Solver/CMakeLists.txt          |   4 +-
 .../solver/NNCGConstraintSolver.cpp           |   2 +-
 .../lagrangian/solver/NNCGConstraintSolver.h  |   6 +-
 .../ProjectedGaussSeidelConstraintSolver.cpp  | 294 ------------------
 .../ProjectedGaussSeidelConstraintSolver.h    |  40 ---
 .../constraint/lagrangian/solver/init.cpp     |   4 +-
 .../tests/BaseTetrahedronFEMForceField_test.h |   2 +-
 .../src/sofa/helper/ComponentChange.cpp       |   2 +-
 .../Helper/src/sofa/helper/SelectableItem.h   |   2 +-
 ...jectedGaussSeidelConstraintSolver_test.cpp |   6 +-
 examples/SimpleAPI/fallingSOFA.cpp            |   2 +-
 13 files changed, 20 insertions(+), 354 deletions(-)
 delete mode 100644 Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.cpp
 delete mode 100644 Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h

diff --git a/Sofa/Component/AnimationLoop/src/sofa/component/animationloop/FreeMotionAnimationLoop.cpp b/Sofa/Component/AnimationLoop/src/sofa/component/animationloop/FreeMotionAnimationLoop.cpp
index 8dc8ddc9536..ec7e3668a17 100644
--- a/Sofa/Component/AnimationLoop/src/sofa/component/animationloop/FreeMotionAnimationLoop.cpp
+++ b/Sofa/Component/AnimationLoop/src/sofa/component/animationloop/FreeMotionAnimationLoop.cpp
@@ -44,11 +44,11 @@
 #include <sofa/simulation/CollisionVisitor.h>
 #include <sofa/simulation/SolveVisitor.h>
 #include <sofa/simulation/MainTaskSchedulerFactory.h>
-#include <sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h>
+#include <sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h>
 
 #include <sofa/simulation/mechanicalvisitor/MechanicalVInitVisitor.h>
 
-#include <sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h>
+#include <sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h>
 using sofa::simulation::mechanicalvisitor::MechanicalVInitVisitor;
 
 
@@ -71,7 +71,7 @@ using namespace core::behavior;
 using namespace sofa::simulation;
 using sofa::helper::ScopedAdvancedTimer;
 
-using DefaultConstraintSolver = sofa::component::constraint::lagrangian::solver::ProjectedGaussSeidelConstraintSolver;
+using DefaultConstraintSolver = sofa::component::constraint::lagrangian::solver::BlockGaussSeidelConstraintSolver;
 
 FreeMotionAnimationLoop::FreeMotionAnimationLoop() :
     d_solveVelocityConstraintFirst(initData(&d_solveVelocityConstraintFirst , false, "solveVelocityConstraintFirst", "solve separately velocity constraint violations before position constraint violations"))
@@ -104,7 +104,7 @@ void FreeMotionAnimationLoop::init()
         l_constraintSolver.set(this->getContext()->get<sofa::core::behavior::ConstraintSolver>(core::objectmodel::BaseContext::SearchDown));
         if (!l_constraintSolver)
         {
-            if (const auto constraintSolver = sofa::core::objectmodel::New<constraint::lagrangian::solver::ProjectedGaussSeidelConstraintSolver>())
+            if (const auto constraintSolver = sofa::core::objectmodel::New<constraint::lagrangian::solver::BlockGaussSeidelConstraintSolver>())
             {
                 getContext()->addObject(constraintSolver);
                 constraintSolver->setName( this->getContext()->getNameHelper().resolveName(constraintSolver->getClassName(), {}));
diff --git a/Sofa/Component/Constraint/Lagrangian/Model/tests/scenes_test/BilateralInteractionConstraint.scn b/Sofa/Component/Constraint/Lagrangian/Model/tests/scenes_test/BilateralInteractionConstraint.scn
index 21bd26bf1af..dada2fe376d 100644
--- a/Sofa/Component/Constraint/Lagrangian/Model/tests/scenes_test/BilateralInteractionConstraint.scn
+++ b/Sofa/Component/Constraint/Lagrangian/Model/tests/scenes_test/BilateralInteractionConstraint.scn
@@ -2,7 +2,7 @@
 <Node name="root" dt="0.001" gravity="0 -981 0">
     <VisualStyle displayFlags="showForceFields" />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIterations="100" tolerance="1e-3" />
+    <BlockGaussSeidelConstraintSolver maxIterations="100" tolerance="1e-3" />
     <CollisionPipeline  depth="6" verbose="0" draw="0" />
     <BruteForceBroadPhase/>
     <BVHNarrowPhase/>
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/CMakeLists.txt b/Sofa/Component/Constraint/Lagrangian/Solver/CMakeLists.txt
index e9395e32b19..c96adb5c931 100644
--- a/Sofa/Component/Constraint/Lagrangian/Solver/CMakeLists.txt
+++ b/Sofa/Component/Constraint/Lagrangian/Solver/CMakeLists.txt
@@ -13,7 +13,7 @@ set(HEADER_FILES
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/BuiltConstraintSolver.h
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/ImprovedJacobiConstraintSolver.h
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/NNCGConstraintSolver.h
-    ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/ProjectedGaussSeidelConstraintSolver.h
+    ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/BlockGaussSeidelConstraintSolver.h
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/UnbuiltConstraintSolver.h
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/UnbuiltGaussSeidelConstraintSolver.h
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/LCPConstraintSolver.h
@@ -32,7 +32,7 @@ set(SOURCE_FILES
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/BuiltConstraintSolver.cpp
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/ImprovedJacobiConstraintSolver.cpp
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/NNCGConstraintSolver.cpp
-    ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/ProjectedGaussSeidelConstraintSolver.cpp
+    ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/BlockGaussSeidelConstraintSolver.cpp
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/UnbuiltConstraintSolver.cpp
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/UnbuiltGaussSeidelConstraintSolver.cpp
     ${SOFACOMPONENTCONSTRAINTLAGRANGIANSOLVER_SOURCE_DIR}/LCPConstraintSolver.cpp
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.cpp b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.cpp
index bbcb2b6f17d..393e86140f7 100644
--- a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.cpp
+++ b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.cpp
@@ -91,7 +91,7 @@ void NNCGConstraintSolver::doSolve(GenericConstraintProblem * problem , SReal ti
     sofa::type::vector<SReal> tabErrors(dimension);
 
     {
-        // perform one iteration of ProjectedGaussSeidel
+        // perform one iteration of BlockGaussSeidel
         bool constraintsAreVerified = true;
 
         std::copy_n(force, dimension, std::begin(problem->m_lam));
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.h b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.h
index 26bd9e95eed..fbf1ae53ebb 100644
--- a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.h
+++ b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/NNCGConstraintSolver.h
@@ -21,15 +21,15 @@
 ******************************************************************************/
 #pragma once
 
-#include <sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h>
+#include <sofa/component/constraint/lagrangian/solver/BlockGaussSeidelConstraintSolver.h>
 #include <sofa/core/behavior/ConstraintResolution.h>
 
 namespace sofa::component::constraint::lagrangian::solver
 {
-class SOFA_COMPONENT_CONSTRAINT_LAGRANGIAN_SOLVER_API NNCGConstraintSolver : public ProjectedGaussSeidelConstraintSolver
+class SOFA_COMPONENT_CONSTRAINT_LAGRANGIAN_SOLVER_API NNCGConstraintSolver : public BlockGaussSeidelConstraintSolver
 {
 public:
-    SOFA_CLASS(NNCGConstraintSolver, ProjectedGaussSeidelConstraintSolver);
+    SOFA_CLASS(NNCGConstraintSolver, BlockGaussSeidelConstraintSolver);
 
     virtual void doSolve(GenericConstraintProblem * problem , SReal timeout = 0.0) override;
 };
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.cpp b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.cpp
deleted file mode 100644
index eebc1b03764..00000000000
--- a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.cpp
+++ /dev/null
@@ -1,294 +0,0 @@
-/******************************************************************************
-*                 SOFA, Simulation Open-Framework Architecture                *
-*                    (c) 2006 INRIA, USTL, UJF, CNRS, MGH                     *
-*                                                                             *
-* This program 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 program 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 program. If not, see <http://www.gnu.org/licenses/>.        *
-*******************************************************************************
-* Authors: The SOFA Team and external contributors (see Authors.txt)          *
-*                                                                             *
-* Contact information: contact@sofa-framework.org                             *
-******************************************************************************/
-
-#include <sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h>
-#include <sofa/component/constraint/lagrangian/solver/GenericConstraintSolver.h>
-#include <sofa/helper/AdvancedTimer.h>
-#include <sofa/helper/ScopedAdvancedTimer.h>
-#include <sofa/core/ObjectFactory.h>
-
-namespace sofa::component::constraint::lagrangian::solver
-{
-
-
-void ProjectedGaussSeidelConstraintSolver::doSolve( GenericConstraintProblem * problem ,SReal timeout)
-{
-    SCOPED_TIMER_VARNAME(gaussSeidelTimer, "ConstraintsGaussSeidel");
-
-
-
-    const int dimension = problem->getDimension();
-
-    if(!dimension)
-    {
-        problem->currentError = 0.0;
-        problem->currentIterations = 0;
-        return;
-    }
-
-    const SReal t0 = (SReal)sofa::helper::system::thread::CTime::getTime() ;
-    const SReal timeScale = 1.0 / (SReal)sofa::helper::system::thread::CTime::getTicksPerSec();
-
-
-    SReal *dfree = problem->getDfree();
-    SReal *force = problem->getF();
-    SReal **w = problem->getW();
-    SReal tol = problem->tolerance;
-    SReal *d = problem->_d.ptr();
-
-    SReal error=0.0;
-    bool convergence = false;
-    sofa::type::vector<SReal> tempForces;
-
-    if(problem->sor != 1.0)
-    {
-        tempForces.resize(dimension);
-    }
-
-    if(problem->scaleTolerance && !problem->allVerified)
-    {
-        tol *= dimension;
-    }
-
-    for(int i=0; i<dimension; )
-    {
-        if(!problem->constraintsResolutions[i])
-        {
-            msg_error()<< "Bad size of constraintsResolutions in GenericConstraintSolver" ;
-            break;
-        }
-        problem->constraintsResolutions[i]->init(i, w, force);
-        i += problem->constraintsResolutions[i]->getNbLines();
-    }
-
-    bool showGraphs = false;
-    sofa::type::vector<SReal>* graph_residuals = nullptr;
-    std::map < std::string, sofa::type::vector<SReal> > *graph_forces = nullptr, *graph_violations = nullptr;
-
-    showGraphs = d_computeGraphs.getValue();
-
-    if(showGraphs)
-    {
-        graph_forces = d_graphForces.beginEdit();
-        graph_forces->clear();
-
-        graph_violations = d_graphViolations.beginEdit();
-        graph_violations->clear();
-
-        graph_residuals = &(*d_graphErrors.beginEdit())["Error"];
-        graph_residuals->clear();
-    }
-
-    sofa::type::vector<SReal> tabErrors(dimension);
-
-    int iterCount = 0;
-
-
-    for(int i=0; i<problem->maxIterations; i++)
-    {
-        iterCount ++;
-        bool constraintsAreVerified = true;
-
-
-        if(problem->sor != 1.0)
-        {
-            std::copy_n(force, dimension, tempForces.begin());
-        }
-
-        error=0.0;
-
-        gaussSeidel_increment(true, dfree, force, w, tol, d, dimension, constraintsAreVerified, error, problem->constraintsResolutions, tabErrors);
-
-        if(showGraphs)
-        {
-            for(int j=0; j<dimension; j++)
-            {
-                std::ostringstream oss;
-                oss << "f" << j;
-
-                sofa::type::vector<SReal>& graph_force = (*graph_forces)[oss.str()];
-                graph_force.push_back(force[j]);
-
-                sofa::type::vector<SReal>& graph_violation = (*graph_violations)[oss.str()];
-                graph_violation.push_back(d[j]);
-            }
-
-            graph_residuals->push_back(error);
-        }
-
-        if(problem->sor != 1.0)
-        {
-            for(int j=0; j<dimension; j++)
-            {
-                force[j] = problem->sor * force[j] + (1-problem->sor) * tempForces[j];
-            }
-        }
-
-        const SReal t1 = (SReal)sofa::helper::system::thread::CTime::getTime();
-        const SReal dt = (t1 - t0)*timeScale;
-
-        if(timeout && dt > timeout)
-        {
-
-            msg_info() <<  "TimeOut" ;
-
-            problem->currentError = error;
-            problem->currentIterations = i+1;
-            return;
-        }
-        else if(problem->allVerified)
-        {
-            if(constraintsAreVerified)
-            {
-                convergence = true;
-                break;
-            }
-        }
-        else if(error < tol) // do not stop at the first iteration (that is used for initial guess computation)
-        {
-            convergence = true;
-            break;
-        }
-    }
-
-    sofa::helper::AdvancedTimer::valSet("GS iterations", problem->currentIterations);
-
-    problem->result_output(this, force, error, iterCount, convergence);
-
-    if(showGraphs)
-    {
-        d_graphErrors.endEdit();
-
-        sofa::type::vector<SReal>& graph_constraints = (*d_graphConstraints.beginEdit())["Constraints"];
-        graph_constraints.clear();
-
-        for(int j=0; j<dimension; )
-        {
-            const unsigned int nbDofs = problem->constraintsResolutions[j]->getNbLines();
-
-            if(tabErrors[j])
-                graph_constraints.push_back(tabErrors[j]);
-            else if(problem->constraintsResolutions[j]->getTolerance())
-                graph_constraints.push_back(problem->constraintsResolutions[j]->getTolerance());
-            else
-                graph_constraints.push_back(tol);
-
-            j += nbDofs;
-        }
-        d_graphConstraints.endEdit();
-
-        d_graphForces.endEdit();
-    }
-}
-
-void ProjectedGaussSeidelConstraintSolver::gaussSeidel_increment(bool measureError, SReal *dfree, SReal *force, SReal **w, SReal tol, SReal *d, int dim, bool& constraintsAreVerified, SReal& error, std::vector<core::behavior::ConstraintResolution*>& constraintCorrections, sofa::type::vector<SReal>& tabErrors) const
-{
-    for(int j=0; j<dim; ) // increment of j realized at the end of the loop
-    {
-        assert(j < constraintCorrections.size());
-        assert(constraintCorrections[j] != nullptr);
-
-        //1. nbLines provide the dimension of the constraint
-        const unsigned int nb = constraintCorrections[j]->getNbLines();
-
-        //2. for each line we compute the actual value of d
-        //   (a)d is set to dfree
-
-        std::vector<SReal> errF(&force[j], &force[j+nb]);
-        std::copy_n(&dfree[j], nb, &d[j]);
-
-        //   (b) contribution of forces are added to d     => TODO => optimization (no computation when force= 0 !!)
-        for(int k=0; k<dim; k++)
-        {
-            for(unsigned int l=0; l<nb; l++)
-            {
-                d[j+l] += w[j+l][k] * force[k];
-            }
-        }
-
-        //3. the specific resolution of the constraint(s) is called
-        constraintCorrections[j]->resolution(j, w, d, force, dfree);
-
-        //4. the error is measured (displacement due to the new resolution (i.e. due to the new force))
-        if(measureError)
-        {
-            SReal contraintError = 0.0;
-            if(nb > 1)
-            {
-                for(unsigned int l=0; l<nb; l++)
-                {
-                    SReal lineError = 0.0;
-                    for (unsigned int m=0; m<nb; m++)
-                    {
-                        const SReal dofError = w[j+l][j+m] * (force[j+m] - errF[m]);
-                        lineError += dofError * dofError;
-                    }
-                    lineError = sqrt(lineError);
-                    if(lineError > tol)
-                    {
-                        constraintsAreVerified = false;
-                    }
-
-                    contraintError += lineError;
-                }
-            }
-            else
-            {
-                contraintError = fabs(w[j][j] * (force[j] - errF[0]));
-                if(contraintError > tol)
-                {
-                    constraintsAreVerified = false;
-                }
-            }
-
-            const bool givenTolerance = (bool)constraintCorrections[j]->getTolerance();
-
-            if(givenTolerance)
-            {
-                if(contraintError > constraintCorrections[j]->getTolerance())
-                {
-                    constraintsAreVerified = false;
-                }
-                contraintError *= tol / constraintCorrections[j]->getTolerance();
-            }
-
-            error += contraintError;
-            tabErrors[j] = contraintError;
-        }
-        else
-        {
-            constraintsAreVerified = true;
-        }
-
-        j += nb;
-    }
-}
-
-
-void registerProjectedGaussSeidelConstraintSolver(sofa::core::ObjectFactory* factory)
-{
-    factory->registerObjects(core::ObjectRegistrationData("A Constraint Solver using the Linear Complementarity Problem formulation to solve Constraint based components using a Projected Gauss-Seidel iterative method")
-        .add< ProjectedGaussSeidelConstraintSolver >());
-}
-
-
-}
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h
deleted file mode 100644
index aabf2c6ef7b..00000000000
--- a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/ProjectedGaussSeidelConstraintSolver.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/******************************************************************************
-*                 SOFA, Simulation Open-Framework Architecture                *
-*                    (c) 2006 INRIA, USTL, UJF, CNRS, MGH                     *
-*                                                                             *
-* This program 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 program 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 program. If not, see <http://www.gnu.org/licenses/>.        *
-*******************************************************************************
-* Authors: The SOFA Team and external contributors (see Authors.txt)          *
-*                                                                             *
-* Contact information: contact@sofa-framework.org                             *
-******************************************************************************/
-#pragma once
-
-#include <sofa/component/constraint/lagrangian/solver/BuiltConstraintSolver.h>
-#include <sofa/core/behavior/ConstraintResolution.h>
-
-namespace sofa::component::constraint::lagrangian::solver
-{
-class SOFA_COMPONENT_CONSTRAINT_LAGRANGIAN_SOLVER_API ProjectedGaussSeidelConstraintSolver : public BuiltConstraintSolver
-{
-public:
-    SOFA_CLASS(ProjectedGaussSeidelConstraintSolver, BuiltConstraintSolver);
-
-protected:
-    virtual void doSolve(GenericConstraintProblem * problem , SReal timeout = 0.0) override;
-
-    void gaussSeidel_increment(bool measureError, SReal *dfree, SReal *force, SReal **w, SReal tol, SReal *d, int dim, bool& constraintsAreVerified, SReal& error, std::vector<core::behavior::ConstraintResolution*>& constraintCorrections, sofa::type::vector<SReal>& tabErrors) const;
-
-};
-}
\ No newline at end of file
diff --git a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/init.cpp b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/init.cpp
index c3cbd2d6ab0..2e4426b180f 100644
--- a/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/init.cpp
+++ b/Sofa/Component/Constraint/Lagrangian/Solver/src/sofa/component/constraint/lagrangian/solver/init.cpp
@@ -27,7 +27,7 @@ namespace sofa::component::constraint::lagrangian::solver
 {
 
 extern void registerNNCGConstraintSolver(sofa::core::ObjectFactory* factory);
-extern void registerProjectedGaussSeidelConstraintSolver(sofa::core::ObjectFactory* factory);
+extern void registerBlockGaussSeidelConstraintSolver(sofa::core::ObjectFactory* factory);
 extern void registerUnbuiltGaussSeidelConstraintSolver(sofa::core::ObjectFactory* factory);
 extern void registerLCPConstraintSolver(sofa::core::ObjectFactory* factory);
 extern void registerImprovedJacobiConstraintSolver(sofa::core::ObjectFactory* factory);
@@ -57,7 +57,7 @@ const char* getModuleVersion()
 void registerObjects(sofa::core::ObjectFactory* factory)
 {
     registerNNCGConstraintSolver(factory);
-    registerProjectedGaussSeidelConstraintSolver(factory);
+    registerBlockGaussSeidelConstraintSolver(factory);
     registerUnbuiltGaussSeidelConstraintSolver(factory);
     registerLCPConstraintSolver(factory);
     registerImprovedJacobiConstraintSolver(factory);
diff --git a/Sofa/Component/SolidMechanics/FEM/Elastic/tests/BaseTetrahedronFEMForceField_test.h b/Sofa/Component/SolidMechanics/FEM/Elastic/tests/BaseTetrahedronFEMForceField_test.h
index 5d1b92953b6..f19c9d27127 100644
--- a/Sofa/Component/SolidMechanics/FEM/Elastic/tests/BaseTetrahedronFEMForceField_test.h
+++ b/Sofa/Component/SolidMechanics/FEM/Elastic/tests/BaseTetrahedronFEMForceField_test.h
@@ -137,7 +137,7 @@ class BaseTetrahedronFEMForceField_test : public sofa::testing::BaseTest
             Sofa.Component.Constraint.Projective
         });
 
-        simpleapi::createObject(m_root, "ProjectedGaussSeidelConstraintSolver", { {"tolerance", "1e-3"}, {"maxIt", "1000"} });
+        simpleapi::createObject(m_root, "BlockGaussSeidelConstraintSolver", { {"tolerance", "1e-3"}, {"maxIt", "1000"} });
 
         simpleapi::createObject(m_root, "RegularGridTopology", { {"name", "grid"},
                     {"n", sofa::simpleapi::str(nbrGrid)}, {"min", "0 0 20"}, {"max", "10 40 30"} });
diff --git a/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp b/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp
index 91dd6a0ef14..9dfb443e592 100644
--- a/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp
+++ b/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp
@@ -626,7 +626,7 @@ std::map<std::string, ComponentChange, std::less<> > uncreatableComponents = {
 
     { "GenericConstraintSolver",
         ComponentChange().withCustomMessage("GenericConstraintSolver has been replaced since v25.12 by a set of new components, whose names relate to the method used:\n"
-             "    - ProjectedGaussSeidelConstraintSolver (if you were using this component without setting 'resolutionMethod' or by setting it to 'ProjectedGaussSeidel')\n"
+             "    - BlockGaussSeidelConstraintSolver (if you were using this component without setting 'resolutionMethod' or by setting it to 'ProjectedGaussSeidel')\n"
              "    - UnbuiltGaussSeidelConstraintSolver (if you were using this component while setting 'resolutionMethod=\"UnbuiltGaussSeidel\"')\n"
              "    - NNCGConstraintSolver (if you were using this component while setting 'resolutionMethod=\"NonsmoothNonlinearConjugateGradient\"')\n"
              "      --> For NNCGConstraintSolver, data 'newtonIterations' has been replaced by 'maxIterations'"
diff --git a/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h b/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h
index 06a86c4cc9b..215031ccdf9 100644
--- a/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h
+++ b/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h
@@ -66,7 +66,7 @@ struct DeprecatedItem
  *
  * Example:
  * MAKE_SELECTABLE_ITEMS(ResolutionMethod,
- *      sofa::helper::Item{"ProjectedGaussSeidel", "Projected Gauss-Seidel"},
+ *      sofa::helper::Item{"BlockGaussSeidel", "Projected Gauss-Seidel"},
  *      sofa::helper::Item{"UnbuiltGaussSeidel", "Gauss-Seidel no matrix assembly"},
  *      sofa::helper::Item{"NonsmoothNonlinearConjugateGradient", "Non-smooth non-linear conjugate gradient"}
  *  );
diff --git a/Sofa/framework/Simulation/Core/tests/ProjectedGaussSeidelConstraintSolver_test.cpp b/Sofa/framework/Simulation/Core/tests/ProjectedGaussSeidelConstraintSolver_test.cpp
index 077892b374b..be26789e876 100644
--- a/Sofa/framework/Simulation/Core/tests/ProjectedGaussSeidelConstraintSolver_test.cpp
+++ b/Sofa/framework/Simulation/Core/tests/ProjectedGaussSeidelConstraintSolver_test.cpp
@@ -30,7 +30,7 @@ namespace
 
 /** Test the UncoupledConstraintCorrection class
 */
-struct ProjectedGaussSeidelConstraintSolver_test : BaseSimulationTest
+struct BlockGaussSeidelConstraintSolver_test : BaseSimulationTest
 {
     void SetUp() override
     {
@@ -49,7 +49,7 @@ struct ProjectedGaussSeidelConstraintSolver_test : BaseSimulationTest
                     "   <RequiredPlugin name='Sofa.Component.Collision.Detection.Intersection'/>"
                     "   <RequiredPlugin name='Sofa.Component.Collision.Response.Contact'/>"
                     "   <FreeMotionAnimationLoop />\n"
-                    "   <ProjectedGaussSeidelConstraintSolver name='solver' constraintForces='-1 -1 -1' computeConstraintForces='True' maxIt='1000' tolerance='0.001' />\n"
+                    "   <BlockGaussSeidelConstraintSolver name='solver' constraintForces='-1 -1 -1' computeConstraintForces='True' maxIt='1000' tolerance='0.001' />\n"
                     "   <Node name='collision'>\n"
                     "         <MechanicalObject />\n"
                     "         <UncoupledConstraintCorrection useOdeSolverIntegrationFactors='0' />\n"
@@ -66,7 +66,7 @@ struct ProjectedGaussSeidelConstraintSolver_test : BaseSimulationTest
 };
 
 /// run the tests
-TEST_F(ProjectedGaussSeidelConstraintSolver_test, checkConstraintForce)
+TEST_F(BlockGaussSeidelConstraintSolver_test, checkConstraintForce)
 {
     EXPECT_MSG_NOEMIT(Error);
     enableConstraintForce();
diff --git a/examples/SimpleAPI/fallingSOFA.cpp b/examples/SimpleAPI/fallingSOFA.cpp
index 4425463eab6..24ed0ef3b42 100644
--- a/examples/SimpleAPI/fallingSOFA.cpp
+++ b/examples/SimpleAPI/fallingSOFA.cpp
@@ -49,7 +49,7 @@ sofa::simulation::Node::SPtr createScene(const sofa::simpleapi::Simulation::SPtr
     sofa::simpleapi::createObject(root, "VisualStyle", {{"displayFlags", "showVisual"}});
     sofa::simpleapi::createObject(root, "ConstraintAttachButtonSetting");
     sofa::simpleapi::createObject(root, "FreeMotionAnimationLoop");
-    sofa::simpleapi::createObject(root, "ProjectedGaussSeidelConstraintSolver",{{"maxIterations","50"}, {"tolerance","1.0e-6"}});
+    sofa::simpleapi::createObject(root, "BlockGaussSeidelConstraintSolver",{{"maxIterations","50"}, {"tolerance","1.0e-6"}});
 
     sofa::simpleapi::createObject(root, "CollisionPipeline",{{"name","Pipeline"}});
     sofa::simpleapi::createObject(root, "ParallelBruteForceBroadPhase",{{"name","BroadPhase"}});

From 4eebc44c71ae718137a20e881bccd8d2ddce143c Mon Sep 17 00:00:00 2001
From: Paul Baksic <paul.baksic@outlook.fr>
Date: Mon, 1 Dec 2025 11:38:10 +0100
Subject: [PATCH 3/4] Apply changes to scenes

---
 .../ArticulatedSystemPlugin/examples/ArticulatedArm/header.py | 2 +-
 applications/plugins/PersistentContact/examples/grasping.scn  | 2 +-
 applications/plugins/Sensable/examples/SimpleBox-Method2.scn  | 2 +-
 applications/plugins/SofaHAPI/examples/SofaHAPI1.scn          | 2 +-
 .../plugins/SofaMatrix/examples/ComplianceMatrixExporter.scn  | 2 +-
 .../plugins/SofaMatrix/examples/ComplianceMatrixImage.scn     | 2 +-
 applications/plugins/Xitact/examples/xitactTest.scn           | 2 +-
 .../src/SceneChecking/SceneCheckCollisionResponse.cpp         | 4 ++--
 examples/Benchmark/Performance/TorusFall.scn                  | 2 +-
 .../Component/Collision/Response/RuleBasedContactManager.scn  | 2 +-
 .../Lagrangian/BilateralLagrangianConstraint_PGS.scn          | 2 +-
 .../Lagrangian/BilateralLagrangianConstraint_Rigid.scn        | 2 +-
 .../BilateralLagrangianConstraint_Soft_Rigid_Bodies.scn       | 2 +-
 ...teralLagrangianConstraint_with_regularization_solvable.scn | 2 +-
 ...ralLagrangianConstraint_with_regularization_unsolvable.scn | 2 +-
 ...lLagrangianConstraint_with_svd_regularization_solvable.scn | 2 +-
 .../Constraint/Lagrangian/FixedLagrangianConstaint_Rigid3.scn | 2 +-
 .../Constraint/Lagrangian/FixedLagrangianConstaint_Vec3.scn   | 2 +-
 .../Lagrangian/FrictionContact_VelocityConstraints.scn        | 2 +-
 .../Component/Constraint/Lagrangian/InextensiblePendulum.scn  | 2 +-
 .../Constraint/Lagrangian/SlidingLagrangianConstraint.scn     | 2 +-
 .../Projective/LinearVelocityProjectiveConstraint.scn         | 2 +-
 examples/Component/Mapping/Linear/DistanceToPlaneMapping.scn  | 2 +-
 examples/Component/Mapping/NonLinear/AreaMapping.scn          | 2 +-
 .../FEM/Heterogeneous-TetrahedronFEMForceField.scn            | 2 +-
 .../SolidMechanics/Spring/RestShapeSpringsForceField2.scn     | 2 +-
 examples/Demos/SofaScene.scn                                  | 2 +-
 examples/Demos/SofaWasher.scn                                 | 2 +-
 examples/Demos/fallingBeamAugmentedLagrangianCollision.scn    | 2 +-
 examples/Demos/fallingBeamLagrangianCollision.scn             | 2 +-
 examples/Demos/fallingSOFA.scn                                | 2 +-
 examples/Demos/sofa_1000PR.scn                                | 2 +-
 32 files changed, 33 insertions(+), 33 deletions(-)

diff --git a/applications/plugins/ArticulatedSystemPlugin/examples/ArticulatedArm/header.py b/applications/plugins/ArticulatedSystemPlugin/examples/ArticulatedArm/header.py
index 2df9619b8a8..19614f0b782 100644
--- a/applications/plugins/ArticulatedSystemPlugin/examples/ArticulatedArm/header.py
+++ b/applications/plugins/ArticulatedSystemPlugin/examples/ArticulatedArm/header.py
@@ -6,7 +6,7 @@ def addHeader(rootNode):
 
     rootNode.addObject('DefaultVisualManagerLoop')
     rootNode.addObject('FreeMotionAnimationLoop')
-    rootNode.addObject('ProjectedGaussSeidelConstraintSolver', maxIterations=50, tolerance=1e-5, printLog=False)
+    rootNode.addObject('BlockGaussSeidelConstraintSolver', maxIterations=50, tolerance=1e-5, printLog=False)
     rootNode.addObject('BackgroundSetting', color=[1., 1., 1., 1.])
     rootNode.findData('dt').value=0.01
     rootNode.gravity = [0,-9810,0]
diff --git a/applications/plugins/PersistentContact/examples/grasping.scn b/applications/plugins/PersistentContact/examples/grasping.scn
index 2c221faff97..7d735b6f864 100644
--- a/applications/plugins/PersistentContact/examples/grasping.scn
+++ b/applications/plugins/PersistentContact/examples/grasping.scn
@@ -2,7 +2,7 @@
 
 	<VisualStyle displayFlags="hideVisual showCollisionModels" />
 	
-	<ProjectedGaussSeidelConstraintSolver tolerance="1e-6" printLog="0" maxIterations="200"/>
+	<BlockGaussSeidelConstraintSolver tolerance="1e-6" printLog="0" maxIterations="200"/>
 	<FreeMotionAnimationLoop/>
 	
 	<CollisionPipeline depth="6" verbose="0" draw="0"/>
diff --git a/applications/plugins/Sensable/examples/SimpleBox-Method2.scn b/applications/plugins/Sensable/examples/SimpleBox-Method2.scn
index 30fa16c5bf9..2f2e4c722b6 100644
--- a/applications/plugins/Sensable/examples/SimpleBox-Method2.scn
+++ b/applications/plugins/Sensable/examples/SimpleBox-Method2.scn
@@ -7,7 +7,7 @@
     <RequiredPlugin pluginName="Sensable" />
 
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver />
+    <BlockGaussSeidelConstraintSolver />
 
     <CollisionPipeline depth="8" />
     <BruteForceBroadPhase/>
diff --git a/applications/plugins/SofaHAPI/examples/SofaHAPI1.scn b/applications/plugins/SofaHAPI/examples/SofaHAPI1.scn
index 6d44a4ee7bf..095b4841d8a 100644
--- a/applications/plugins/SofaHAPI/examples/SofaHAPI1.scn
+++ b/applications/plugins/SofaHAPI/examples/SofaHAPI1.scn
@@ -7,7 +7,7 @@
     <RequiredPlugin pluginName="SofaHAPI" />
 
 	<FreeMotionAnimationLoop />
-	<ProjectedGaussSeidelConstraintSolver />
+	<BlockGaussSeidelConstraintSolver />
 
 	<CollisionPipeline depth="8" />
 	<BruteForceBroadPhase/>
diff --git a/applications/plugins/SofaMatrix/examples/ComplianceMatrixExporter.scn b/applications/plugins/SofaMatrix/examples/ComplianceMatrixExporter.scn
index eeb60a8b0b0..fd5474a707b 100644
--- a/applications/plugins/SofaMatrix/examples/ComplianceMatrixExporter.scn
+++ b/applications/plugins/SofaMatrix/examples/ComplianceMatrixExporter.scn
@@ -17,7 +17,7 @@
 
     <VisualStyle displayFlags="hideVisualModels showBehaviorModels showMappings showForceFields" />
     <FreeMotionAnimationLoop solveVelocityConstraintFirst="true" />
-    <ProjectedGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
     <ComplianceMatrixExporter exportEveryNumberOfSteps="1" filename="compliance" printLog="true" format="csv" precision="12"/>
 
     <StringMeshCreator name="loader" resolution="20" scale3d="1 1 1" />
diff --git a/applications/plugins/SofaMatrix/examples/ComplianceMatrixImage.scn b/applications/plugins/SofaMatrix/examples/ComplianceMatrixImage.scn
index 660f53115ec..4fab1497825 100644
--- a/applications/plugins/SofaMatrix/examples/ComplianceMatrixImage.scn
+++ b/applications/plugins/SofaMatrix/examples/ComplianceMatrixImage.scn
@@ -17,7 +17,7 @@
 
     <VisualStyle displayFlags="hideVisualModels showBehaviorModels showMappings showForceFields" />
     <FreeMotionAnimationLoop solveVelocityConstraintFirst="true" />
-    <ProjectedGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
     <ComplianceMatrixImage/>
 
     <StringMeshCreator name="loader" resolution="20" scale3d="1 1 1" />
diff --git a/applications/plugins/Xitact/examples/xitactTest.scn b/applications/plugins/Xitact/examples/xitactTest.scn
index c2680fa0ee5..699c87ac41f 100644
--- a/applications/plugins/Xitact/examples/xitactTest.scn
+++ b/applications/plugins/Xitact/examples/xitactTest.scn
@@ -3,7 +3,7 @@
     <RequiredPlugin name="SofaOpenglVisual"/>
 	<VisualStyle displayFlags="showVisualModels hideBehaviorModels showCollisionModels hideMappings hideForceFields" />
 	<FreeMotionAnimationLoop />
-	<ProjectedGaussSeidelConstraintSolver/>
+	<BlockGaussSeidelConstraintSolver/>
 	<CollisionPipeline depth="6" verbose="0" draw="0"/>
 	<BruteForceBroadPhase/>
     <BVHNarrowPhase/>
diff --git a/applications/projects/SceneChecking/src/SceneChecking/SceneCheckCollisionResponse.cpp b/applications/projects/SceneChecking/src/SceneChecking/SceneCheckCollisionResponse.cpp
index 8c559aee30f..687eec987c3 100644
--- a/applications/projects/SceneChecking/src/SceneChecking/SceneCheckCollisionResponse.cpp
+++ b/applications/projects/SceneChecking/src/SceneChecking/SceneCheckCollisionResponse.cpp
@@ -82,9 +82,9 @@ void SceneCheckCollisionResponse::doCheckOn(Node* node)
 
                 sofa::core::behavior::ConstraintSolver* constraintSolver;
                 root->get(constraintSolver, sofa::core::objectmodel::BaseContext::SearchRoot);
-                if (!constraintSolver || ( constraintSolver && ( constraintSolver->getClassName() != "ProjectedGaussSeidelConstraintSolver" )) )
+                if (!constraintSolver || ( constraintSolver && ( constraintSolver->getClassName() != "BlockGaussSeidelConstraintSolver" )) )
                 {
-                    m_message <<"A ProjectedGaussSeidelConstraintSolver must be in the scene to solve StickContactConstraint" << msgendl;
+                    m_message <<"A BlockGaussSeidelConstraintSolver must be in the scene to solve StickContactConstraint" << msgendl;
                 }
             }
             /// If FrictionContactConstraint is chosen, make sure the scene includes a FreeMotionAnimationLoop
diff --git a/examples/Benchmark/Performance/TorusFall.scn b/examples/Benchmark/Performance/TorusFall.scn
index 1f24dba9312..14617707a33 100644
--- a/examples/Benchmark/Performance/TorusFall.scn
+++ b/examples/Benchmark/Performance/TorusFall.scn
@@ -30,7 +30,7 @@
   <VisualStyle displayFlags="showVisual showCollisionModels hideBehaviorModels showForceFields hideInteractionForceFields hideWireframe" />
 
   <FreeMotionAnimationLoop name="animationLoop" solveVelocityConstraintFirst="true" parallelCollisionDetectionAndFreeMotion="true" parallelODESolving="true"/>
-  <ProjectedGaussSeidelConstraintSolver name="constraintSolver" maxIterations="100" tolerance="1.0e-9" multithreading="true"/>
+  <BlockGaussSeidelConstraintSolver name="constraintSolver" maxIterations="100" tolerance="1.0e-9" multithreading="true"/>
   <CollisionPipeline name="Pipeline" />
   <BruteForceBroadPhase name="BroadPhase" />
   <BVHNarrowPhase name="NarrowPhase" />
diff --git a/examples/Component/Collision/Response/RuleBasedContactManager.scn b/examples/Component/Collision/Response/RuleBasedContactManager.scn
index 24ba8ed5c7d..0c2cee4c509 100644
--- a/examples/Component/Collision/Response/RuleBasedContactManager.scn
+++ b/examples/Component/Collision/Response/RuleBasedContactManager.scn
@@ -20,7 +20,7 @@
     
     <VisualStyle displayFlags="showBehaviorModels showVisual" />
     <FreeMotionAnimationLoop />
-	<ProjectedGaussSeidelConstraintSolver maxIterations="1000" tolerance="0.001"/>
+	<BlockGaussSeidelConstraintSolver maxIterations="1000" tolerance="0.001"/>
     <CollisionPipeline depth="6" verbose="0" draw="0" />
     <BruteForceBroadPhase/>
     <BVHNarrowPhase/>
diff --git a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_PGS.scn b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_PGS.scn
index bfa2d71c677..510e0348a13 100644
--- a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_PGS.scn
+++ b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_PGS.scn
@@ -22,7 +22,7 @@
     <VisualStyle displayFlags="showForceFields" />
     <DefaultVisualManagerLoop />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver tolerance="0.001" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="0.001" maxIterations="1000"/>
     <CollisionPipeline depth="6" verbose="0" draw="0" />
     <BruteForceBroadPhase/>
     <BVHNarrowPhase/>
diff --git a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Rigid.scn b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Rigid.scn
index 31f93a6c1e8..fdbce4926d5 100644
--- a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Rigid.scn
+++ b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Rigid.scn
@@ -18,7 +18,7 @@
 
     <VisualStyle displayFlags="showBehaviorModels showForceFields" />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver tolerance="0.001" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="0.001" maxIterations="1000"/>
     <Node name="Beam1">
         <EulerImplicitSolver name="odesolver" printLog="false"  rayleighStiffness="0.1" rayleighMass="0.1" />
         <BTDLinearSolver printLog="false" verbose="false" />
diff --git a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Soft_Rigid_Bodies.scn b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Soft_Rigid_Bodies.scn
index b8f8f81479b..2fb10cbdb0c 100644
--- a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Soft_Rigid_Bodies.scn
+++ b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_Soft_Rigid_Bodies.scn
@@ -28,7 +28,7 @@
 
 
     <FreeMotionAnimationLoop computeBoundingBox="0"/>
-    <ProjectedGaussSeidelConstraintSolver maxIterations="1000" tolerance="1e-3"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="1000" tolerance="1e-3"/>
     
     <VisualStyle displayFlags="showBehaviorModels showVisual showForceFields" />
     <CollisionPipeline name="CollisionLoop" verbose="0" />
diff --git a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_solvable.scn b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_solvable.scn
index 2e10347f367..28d0669d2da 100644
--- a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_solvable.scn
+++ b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_solvable.scn
@@ -17,7 +17,7 @@
     <VisualStyle displayFlags="showForceFields" />
     <DefaultVisualManagerLoop />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver tolerance="0.0001" maxIterations="1000" regularizationTerm="0.0"/>
+    <BlockGaussSeidelConstraintSolver tolerance="0.0001" maxIterations="1000" regularizationTerm="0.0"/>
 
 
     <Node name="TargetCube0">
diff --git a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_unsolvable.scn b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_unsolvable.scn
index 038917c14ae..0ffbb256d61 100644
--- a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_unsolvable.scn
+++ b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_regularization_unsolvable.scn
@@ -17,7 +17,7 @@
     <VisualStyle displayFlags="showForceFields" />
     <DefaultVisualManagerLoop />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver tolerance="0.0001" maxIterations="1000" regularizationTerm="0.0"/>
+    <BlockGaussSeidelConstraintSolver tolerance="0.0001" maxIterations="1000" regularizationTerm="0.0"/>
 
 
     <Node name="TargetCube00">
diff --git a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_svd_regularization_solvable.scn b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_svd_regularization_solvable.scn
index 059c065fca2..34359b48da2 100644
--- a/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_svd_regularization_solvable.scn
+++ b/examples/Component/Constraint/Lagrangian/BilateralLagrangianConstraint_with_svd_regularization_solvable.scn
@@ -17,7 +17,7 @@
     <VisualStyle displayFlags="showForceFields showWireFrame showBehavior" />
     <DefaultVisualManagerLoop />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver tolerance="0.0001" maxIterations="1000" regularizationTerm="1e-3" useSVDForRegularization="true"/>
+    <BlockGaussSeidelConstraintSolver tolerance="0.0001" maxIterations="1000" regularizationTerm="1e-3" useSVDForRegularization="true"/>
 
 
     <Node name="TargetCubeExtrimities">
diff --git a/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Rigid3.scn b/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Rigid3.scn
index adef70eaade..8069d63be0f 100644
--- a/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Rigid3.scn
+++ b/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Rigid3.scn
@@ -21,7 +21,7 @@
     <AttachBodyButtonSetting stiffness="5" /> <!-- The presence of this component sets the mouse interaction to Lagrangian-based constraints at the GUI launch -->
 
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
 
     <Node name="Needle">
         <EulerImplicitSolver  />
diff --git a/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Vec3.scn b/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Vec3.scn
index 2aaf4554dac..502187b38fd 100644
--- a/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Vec3.scn
+++ b/examples/Component/Constraint/Lagrangian/FixedLagrangianConstaint_Vec3.scn
@@ -24,7 +24,7 @@
     <ConstraintAttachButtonSetting /> <!-- The presence of this component sets the mouse interaction to Lagrangian-based constraints at the GUI launch -->
 
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
 
     <!-- $$$$$$$$$$$$$$$$$$$$$$ TOPOLOGY 1 $$$$$$$$$$$$$$$$$$$$$$ -->
     <Node name="BEAMVOLUME">
diff --git a/examples/Component/Constraint/Lagrangian/FrictionContact_VelocityConstraints.scn b/examples/Component/Constraint/Lagrangian/FrictionContact_VelocityConstraints.scn
index 2132cb08012..18f81be1611 100644
--- a/examples/Component/Constraint/Lagrangian/FrictionContact_VelocityConstraints.scn
+++ b/examples/Component/Constraint/Lagrangian/FrictionContact_VelocityConstraints.scn
@@ -16,7 +16,7 @@
     <RequiredPlugin name="Sofa.Component.Visual"/> <!-- Needed to use components [VisualStyle] -->
     <RequiredPlugin name="Sofa.GL.Component.Rendering3D"/> <!-- Needed to use components [OglModel] -->
     <VisualStyle displayFlags="showVisual" />
-    <ProjectedGaussSeidelConstraintSolver tolerance="1e-6" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="1e-6" maxIterations="1000"/>
     <FreeMotionAnimationLoop solveVelocityConstraintFirst="1" />
     <CollisionPipeline depth="15" verbose="0" draw="0" />
     <BruteForceBroadPhase/>
diff --git a/examples/Component/Constraint/Lagrangian/InextensiblePendulum.scn b/examples/Component/Constraint/Lagrangian/InextensiblePendulum.scn
index bba47020525..8a8583d8210 100644
--- a/examples/Component/Constraint/Lagrangian/InextensiblePendulum.scn
+++ b/examples/Component/Constraint/Lagrangian/InextensiblePendulum.scn
@@ -25,7 +25,7 @@
     <VisualStyle displayFlags="showVisualModels showBehaviorModels showMappings showForceFields" />
 
     <FreeMotionAnimationLoop solveVelocityConstraintFirst="true" computeBoundingBox="false"/>
-    <ProjectedGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
     <!-- resolution = number of particles (including the fixed one) -->
     <!-- scale = total length of the pendulum -->
     <!-- 1m long wire -->
diff --git a/examples/Component/Constraint/Lagrangian/SlidingLagrangianConstraint.scn b/examples/Component/Constraint/Lagrangian/SlidingLagrangianConstraint.scn
index c89c3cd609b..7cd56c235e7 100644
--- a/examples/Component/Constraint/Lagrangian/SlidingLagrangianConstraint.scn
+++ b/examples/Component/Constraint/Lagrangian/SlidingLagrangianConstraint.scn
@@ -20,7 +20,7 @@
     
     <VisualStyle displayFlags="showForceFields showVisual showBehavior" />
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIterations="1000" tolerance="0.001"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="1000" tolerance="0.001"/>
     <CollisionPipeline depth="6" verbose="0" draw="0" />
     <BruteForceBroadPhase/>
     <BVHNarrowPhase/>
diff --git a/examples/Component/Constraint/Projective/LinearVelocityProjectiveConstraint.scn b/examples/Component/Constraint/Projective/LinearVelocityProjectiveConstraint.scn
index cdfef263603..5afbb7a9489 100644
--- a/examples/Component/Constraint/Projective/LinearVelocityProjectiveConstraint.scn
+++ b/examples/Component/Constraint/Projective/LinearVelocityProjectiveConstraint.scn
@@ -23,7 +23,7 @@
 
     <!-- # Header of the simulation -->
     <FreeMotionAnimationLoop name="FreeMotionAnimationLoop" parallelODESolving="true" parallelCollisionDetectionAndFreeMotion="true"/>
-    <ProjectedGaussSeidelConstraintSolver maxIterations="1000" tolerance="0.001" />
+    <BlockGaussSeidelConstraintSolver maxIterations="1000" tolerance="0.001" />
 
     <Node name="Box">
         <EulerImplicitSolver name="EulerImplicitScheme" />
diff --git a/examples/Component/Mapping/Linear/DistanceToPlaneMapping.scn b/examples/Component/Mapping/Linear/DistanceToPlaneMapping.scn
index dde370eb370..b3c3af06fa4 100644
--- a/examples/Component/Mapping/Linear/DistanceToPlaneMapping.scn
+++ b/examples/Component/Mapping/Linear/DistanceToPlaneMapping.scn
@@ -14,7 +14,7 @@
 
     <FreeMotionAnimationLoop/>
     <VisualStyle displayFlags="showBehaviorModels showMappings" />
-    <ProjectedGaussSeidelConstraintSolver/>
+    <BlockGaussSeidelConstraintSolver/>
 
 
     <Node name="Langrangian-Bileateral">
diff --git a/examples/Component/Mapping/NonLinear/AreaMapping.scn b/examples/Component/Mapping/NonLinear/AreaMapping.scn
index 08353a4a408..a45c2651fe1 100644
--- a/examples/Component/Mapping/NonLinear/AreaMapping.scn
+++ b/examples/Component/Mapping/NonLinear/AreaMapping.scn
@@ -23,7 +23,7 @@
     </Node>
 
     <FreeMotionAnimationLoop solveVelocityConstraintFirst="true" computeBoundingBox="false" parallelODESolving="true"/>
-    <ProjectedGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
+    <BlockGaussSeidelConstraintSolver tolerance="1e-9" maxIterations="1000"/>
     <VisualStyle displayFlags="showWireframe showBehaviorModels"/>
 
     <RegularGridTopology name="grid" nx="10" ny="10" nz="1" xmin="0" xmax="10" ymin="0" ymax="10" zmin="0" zmax="0" />
diff --git a/examples/Component/SolidMechanics/FEM/Heterogeneous-TetrahedronFEMForceField.scn b/examples/Component/SolidMechanics/FEM/Heterogeneous-TetrahedronFEMForceField.scn
index 23cae4c230c..79655c48bb6 100644
--- a/examples/Component/SolidMechanics/FEM/Heterogeneous-TetrahedronFEMForceField.scn
+++ b/examples/Component/SolidMechanics/FEM/Heterogeneous-TetrahedronFEMForceField.scn
@@ -25,7 +25,7 @@
 
 
     <FreeMotionAnimationLoop/>
-    <ProjectedGaussSeidelConstraintSolver maxIt="500" tolerance="0.0002" scaleTolerance='false' printLog="false" computeConstraintForces="true"/>
+    <BlockGaussSeidelConstraintSolver maxIt="500" tolerance="0.0002" scaleTolerance='false' printLog="false" computeConstraintForces="true"/>
 
 
     <Node name="Topology">
diff --git a/examples/Component/SolidMechanics/Spring/RestShapeSpringsForceField2.scn b/examples/Component/SolidMechanics/Spring/RestShapeSpringsForceField2.scn
index 2af2de80456..5b9427ef279 100644
--- a/examples/Component/SolidMechanics/Spring/RestShapeSpringsForceField2.scn
+++ b/examples/Component/SolidMechanics/Spring/RestShapeSpringsForceField2.scn
@@ -14,7 +14,7 @@
     <VisualStyle displayFlags=" showCollisionModels showForceFields" />
 
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIt="1000" tolerance="1e-10" printLog="false" />
+    <BlockGaussSeidelConstraintSolver maxIt="1000" tolerance="1e-10" printLog="false" />
 
     <Node name="Object1">
         <MechanicalObject name="ms" template="Rigid3" position="0 0 0 0 0 0 0 1" showObject="false"/>
diff --git a/examples/Demos/SofaScene.scn b/examples/Demos/SofaScene.scn
index e65b4a1717c..82a12c947eb 100644
--- a/examples/Demos/SofaScene.scn
+++ b/examples/Demos/SofaScene.scn
@@ -42,7 +42,7 @@
 
     <!-- Header of the simulation -->
     <FreeMotionAnimationLoop name="FreeMotionAnimationLoop" parallelODESolving="true" parallelCollisionDetectionAndFreeMotion="true"/>
-    <ProjectedGaussSeidelConstraintSolver maxIterations="20" multithreading='true' tolerance="1.0e-4"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="20" multithreading='true' tolerance="1.0e-4"/>
 
     <!-- Definition of the collision pipeline -->
     <CollisionPipeline name="CollisionPipeline" />
diff --git a/examples/Demos/SofaWasher.scn b/examples/Demos/SofaWasher.scn
index e7f01600304..0317462e7cc 100644
--- a/examples/Demos/SofaWasher.scn
+++ b/examples/Demos/SofaWasher.scn
@@ -32,7 +32,7 @@
 
     <!-- # Header of the simulation -->
     <FreeMotionAnimationLoop name="FreeMotionAnimationLoop" parallelODESolving="true" parallelCollisionDetectionAndFreeMotion="true"/>
-    <ProjectedGaussSeidelConstraintSolver maxIterations="50" multithreading='true' tolerance="1.0e-3"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="50" multithreading='true' tolerance="1.0e-3"/>
 
     <!-- # Definition of the collision pipeline -->
     <CollisionPipeline name="CollisionPipeline" />
diff --git a/examples/Demos/fallingBeamAugmentedLagrangianCollision.scn b/examples/Demos/fallingBeamAugmentedLagrangianCollision.scn
index 324247538c5..2ec3c12b168 100644
--- a/examples/Demos/fallingBeamAugmentedLagrangianCollision.scn
+++ b/examples/Demos/fallingBeamAugmentedLagrangianCollision.scn
@@ -27,7 +27,7 @@
     <VisualStyle displayFlags="showForceFields"/>
     <ConstraintAttachButtonSetting /> <!-- The presence of this component sets the mouse interaction to Lagrangian-based constraints at the GUI launch -->
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
     <CollisionPipeline name="Pipeline" />
     <BruteForceBroadPhase name="BroadPhase" />
     <BVHNarrowPhase name="NarrowPhase" />
diff --git a/examples/Demos/fallingBeamLagrangianCollision.scn b/examples/Demos/fallingBeamLagrangianCollision.scn
index 29e7059ba44..3cb00b82ac1 100644
--- a/examples/Demos/fallingBeamLagrangianCollision.scn
+++ b/examples/Demos/fallingBeamLagrangianCollision.scn
@@ -27,7 +27,7 @@
     <VisualStyle displayFlags="showForceFields"/>
     <ConstraintAttachButtonSetting /> <!-- The presence of this component sets the mouse interaction to Lagrangian-based constraints at the GUI launch -->
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="200" tolerance="1.0e-8"/>
     <CollisionPipeline name="Pipeline" />
     <BruteForceBroadPhase name="BroadPhase" />
     <BVHNarrowPhase name="NarrowPhase" />
diff --git a/examples/Demos/fallingSOFA.scn b/examples/Demos/fallingSOFA.scn
index 978637fd861..c39c440eafa 100644
--- a/examples/Demos/fallingSOFA.scn
+++ b/examples/Demos/fallingSOFA.scn
@@ -38,7 +38,7 @@
     <FreeMotionAnimationLoop computeBoundingBox="false"/>
     <!-- This solver will perform the different constraint solving stages a.k.a. the constraint system building, the constraint solving and the motion correction
      For more information see : https://sofa-framework.github.io/doc/simulation-principles/constraint/lagrange-constraint/ -->
-    <ProjectedGaussSeidelConstraintSolver maxIterations="50" tolerance="1.0e-6"/>
+    <BlockGaussSeidelConstraintSolver maxIterations="50" tolerance="1.0e-6"/>
 
     <!-- Definition of the collision pipeline -->
     <CollisionPipeline name="Pipeline" />
diff --git a/examples/Demos/sofa_1000PR.scn b/examples/Demos/sofa_1000PR.scn
index 7c44da2aa24..006c0bf6c21 100644
--- a/examples/Demos/sofa_1000PR.scn
+++ b/examples/Demos/sofa_1000PR.scn
@@ -24,7 +24,7 @@
     <RequiredPlugin name="Sofa.GL.Component.Rendering3D"/> <!-- Needed to use components [OglModel] -->
 
     <FreeMotionAnimationLoop />
-    <ProjectedGaussSeidelConstraintSolver tolerance="1e-3" maxIt="200" printLog="0" multithreading="true"/>
+    <BlockGaussSeidelConstraintSolver tolerance="1e-3" maxIt="200" printLog="0" multithreading="true"/>
     <CollisionPipeline verbose="0" depth="10" draw="0" />
     <BruteForceBroadPhase/>
     <BVHNarrowPhase/>

From 19399b85b00106daa1a68f337089223e7f22e874 Mon Sep 17 00:00:00 2001
From: Paul Baksic <30337881+bakpaul@users.noreply.github.com>
Date: Wed, 10 Dec 2025 14:22:23 +0100
Subject: [PATCH 4/4] Apply suggestions from code review

Co-authored-by: Themis Skamagkis <70031729+th-skam@users.noreply.github.com>
---
 Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp | 2 +-
 Sofa/framework/Helper/src/sofa/helper/SelectableItem.h    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp b/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp
index 9dfb443e592..306f26c000a 100644
--- a/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp
+++ b/Sofa/framework/Helper/src/sofa/helper/ComponentChange.cpp
@@ -626,7 +626,7 @@ std::map<std::string, ComponentChange, std::less<> > uncreatableComponents = {
 
     { "GenericConstraintSolver",
         ComponentChange().withCustomMessage("GenericConstraintSolver has been replaced since v25.12 by a set of new components, whose names relate to the method used:\n"
-             "    - BlockGaussSeidelConstraintSolver (if you were using this component without setting 'resolutionMethod' or by setting it to 'ProjectedGaussSeidel')\n"
+             "    - BlockGaussSeidelConstraintSolver (if you were using this component without setting 'resolutionMethod' or by setting it to 'BlockGaussSeidel')\n"
              "    - UnbuiltGaussSeidelConstraintSolver (if you were using this component while setting 'resolutionMethod=\"UnbuiltGaussSeidel\"')\n"
              "    - NNCGConstraintSolver (if you were using this component while setting 'resolutionMethod=\"NonsmoothNonlinearConjugateGradient\"')\n"
              "      --> For NNCGConstraintSolver, data 'newtonIterations' has been replaced by 'maxIterations'"
diff --git a/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h b/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h
index 215031ccdf9..1250fda6ccd 100644
--- a/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h
+++ b/Sofa/framework/Helper/src/sofa/helper/SelectableItem.h
@@ -66,7 +66,7 @@ struct DeprecatedItem
  *
  * Example:
  * MAKE_SELECTABLE_ITEMS(ResolutionMethod,
- *      sofa::helper::Item{"BlockGaussSeidel", "Projected Gauss-Seidel"},
+ *      sofa::helper::Item{"BlockGaussSeidel", "Block Gauss-Seidel"},
  *      sofa::helper::Item{"UnbuiltGaussSeidel", "Gauss-Seidel no matrix assembly"},
  *      sofa::helper::Item{"NonsmoothNonlinearConjugateGradient", "Non-smooth non-linear conjugate gradient"}
  *  );