clean up code

8 files changed, 23 insertions, 205 deletions

diff --git a/examples/DeformableDemo/GraspDeformable.cpp b/examples/DeformableDemo/GraspDeformable.cpp
index 285f7c8c8..f52f67fe9 100644
--- a/examples/DeformableDemo/GraspDeformable.cpp
+++ b/examples/DeformableDemo/GraspDeformable.cpp
@@ -35,9 +35,6 @@
 #include "../CommonInterfaces/CommonFileIOInterface.h"
 #include "Bullet3Common/b3FileUtils.h"
 
-#include "../ThirdPartyLibs/Wavefront/tiny_obj_loader.h"
-#include "../src/LinearMath/btScalar.h"
-
 ///The GraspDeformable shows grasping a volumetric deformable objects with multibody gripper with moter constraints.
 static btScalar sGripperVerticalVelocity = 0.f;
 static btScalar sGripperClosingTargetVelocity = 0.f;
@@ -76,7 +73,7 @@ public:
 
 	void resetCamera()
 	{
-        float dist = 0.2;
+        float dist = 0.3;
         float pitch = -45;
         float yaw = 100;
         float targetPos[3] = {0, -0.1, 0};
@@ -205,9 +202,9 @@ void GraspDeformable::initPhysics()
     getDeformableDynamicsWorld()->getSolverInfo().m_deformable_cfm = 0;
     getDeformableDynamicsWorld()->getSolverInfo().m_numIterations = 150;
 	m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld);
-    m_maxPickingForce =100;
+    m_maxPickingForce = 0.001;
     // build a gripper
-    if(0)
+    if(1)
     {
         bool damping = true;
         bool gyro = false;
@@ -257,7 +254,6 @@ void GraspDeformable::initPhysics()
     }
     
     //create a ground
-    if(0)
     {
         btCollisionShape* groundShape = new btBoxShape(btVector3(btScalar(10.), btScalar(5.), btScalar(10.)));
         groundShape->setMargin(0.001);
@@ -265,7 +261,7 @@ void GraspDeformable::initPhysics()
 
         btTransform groundTransform;
         groundTransform.setIdentity();
-        groundTransform.setOrigin(btVector3(0, -5, 0));
+        groundTransform.setOrigin(btVector3(0, -5.1, 0));
         groundTransform.setRotation(btQuaternion(btVector3(1, 0, 0), SIMD_PI * 0));
         //We can also use DemoApplication::localCreateRigidBody, but for clarity it is provided here:
         btScalar mass(0.);
@@ -286,22 +282,6 @@ void GraspDeformable::initPhysics()
         //add the ground to the dynamics world
         m_dynamicsWorld->addRigidBody(body,1,1+2);
     }
-    
-    if(1)
-    {
-             bool gyro = false;
-             bool canSleep = false;
-             bool selfCollide = true;
-             btVector3 linkHalfExtents(10, 5, 10);
-             btVector3 baseHalfExtents(10, 5, 10);
-             btVector3 basepos(0, -5, 0);
-             btMultiBody* mbC = createFeatherstoneMultiBody(getDeformableDynamicsWorld(), basepos, linkHalfExtents, baseHalfExtents, false);
-             
-             mbC->setCanSleep(canSleep);
-             mbC->setHasSelfCollision(selfCollide);
-             mbC->setUseGyroTerm(gyro);
-         addColliders(mbC, getDeformableDynamicsWorld(), baseHalfExtents, linkHalfExtents);
-    }
 
     // create a soft block
 	if (0)
@@ -358,12 +338,12 @@ void GraspDeformable::initPhysics()
     {
         bool onGround = false;
         const btScalar s = .05;
-        const btScalar h = 0.01;
+        const btScalar h = -0.02;
         btSoftBody* psb = btSoftBodyHelpers::CreatePatch(getDeformableDynamicsWorld()->getWorldInfo(), btVector3(-s, h, -s),
                                                          btVector3(+s, h, -s),
                                                          btVector3(-s, h, +s),
                                                          btVector3(+s, h, +s),
-                                                         2,2,
+                                                         10,10,
                                                                   0, true);
 
         if (onGround)
@@ -376,109 +356,19 @@ void GraspDeformable::initPhysics()
                                                  0, true);
 
         psb->getCollisionShape()->setMargin(0.001);
-
-        
         psb->generateBendingConstraints(2);
-        psb->setTotalMass(0.02);
-
+        psb->setTotalMass(0.01);
+        psb->setSpringStiffness(10);
+        psb->setDampingCoefficient(0.05);
         psb->m_cfg.kKHR = 1; // collision hardness with kinematic objects
         psb->m_cfg.kCHR = 1; // collision hardness with rigid body
         psb->m_cfg.kDF = 1;
         psb->m_cfg.collisions = btSoftBody::fCollision::SDF_RD;
         psb->m_cfg.collisions |= btSoftBody::fCollision::SDF_MDF;
         psb->m_cfg.collisions |= btSoftBody::fCollision::SDF_RDF;
-        
         getDeformableDynamicsWorld()->addSoftBody(psb);
-        
-        btScalar elastic_stiffness = 0.2;
-        btScalar damping_stiffness = 0.01;
-        bool not_damp_all_directions = true;
-        btScalar bending_stiffness = 0.2;
-        psb->setSpringStiffness(elastic_stiffness);
-        btDeformableLagrangianForce* springForce =
-        new btDeformableMassSpringForce(elastic_stiffness,
-                                        damping_stiffness, not_damp_all_directions,bending_stiffness);
-        getDeformableDynamicsWorld()->addForce(psb, springForce);
-        getDeformableDynamicsWorld()->addForce(psb, new btDeformableGravityForce(gravity));
-    }
-    
-    if(0){
-        
-              btSoftBody* psb = NULL;
-              
-              std::vector<tinyobj::shape_t> shapes;
-              tinyobj::attrib_t attribute;
-              char absolute_path[1024];
-              b3BulletDefaultFileIO fileio;
-              fileio.findResourcePath("dang_sticky_rice_chips_full_sim.obj", absolute_path, 1024);
-              std::string err = tinyobj::LoadObj(attribute, shapes, absolute_path, "", &fileio);
-              if (!shapes.empty())
-              {
-                  const tinyobj::shape_t& shape = shapes[0];
-                  btAlignedObjectArray<btScalar> vertices;
-                  btAlignedObjectArray<int> indices;
-                  for (int i = 0; i < attribute.vertices.size(); i++)
-                  {
-                      vertices.push_back(attribute.vertices[i]);
-                  }
-                  for (int i = 0; i < shape.mesh.indices.size(); i++)
-                  {
-                      indices.push_back(shape.mesh.indices[i].vertex_index);
-                  }
-                  int numTris = shape.mesh.indices.size() / 3;
-                  if (numTris > 0)
-                  {
-                      psb = btSoftBodyHelpers::CreateFromTriMesh(   getDeformableDynamicsWorld()->getWorldInfo(), &vertices[0], &indices[0], numTris);
-                      
-                      btAssert(psb!=nullptr);
-                  }
-                  btScalar elastic_stiffness = 0.2;
-                  btScalar damping_stiffness = 0.01;
-                  bool not_damp_all_directions = true;
-                  btScalar bending_stiffness = 0.2;
-                  btDeformableLagrangianForce* springForce =
-                  new btDeformableMassSpringForce(elastic_stiffness,
-                                                  damping_stiffness, not_damp_all_directions,bending_stiffness);
-                  psb->generateBendingConstraints(3);
-                  getDeformableDynamicsWorld()->addForce(psb, springForce);
-                  m_forces.push_back(springForce);
-                  
-                  btVector3 gravity =getDeformableDynamicsWorld()->getGravity();
-                  btDeformableLagrangianForce* gravityForce = new btDeformableGravityForce(gravity *0.2);
-                  getDeformableDynamicsWorld()->addForce(psb, gravityForce);
-                  m_forces.push_back(gravityForce);
-                  
-                  btScalar friction = 1;
-                  psb->m_cfg.kDF = friction;
-                  
-                  // turn on the collision flag for deformable
-                  // collision between deformable and rigid
-                  psb->m_cfg.collisions = btSoftBody::fCollision::SDF_RD;
-                  // turn on face contact for multibodies
-                  psb->m_cfg.collisions |= btSoftBody::fCollision::SDF_MDF;
-                  /// turn on face contact for rigid body
-                  psb->m_cfg.collisions |= btSoftBody::fCollision::SDF_RDF;
-                  // collion between deformable and deformable and self-collision
-                  psb->m_cfg.collisions |= btSoftBody::fCollision::VF_DD;
-                  psb->setCollisionFlags(0);
-                  
-                  psb->setTotalMass(0.02);
-                  psb->setSelfCollision(false);
-                  btScalar repulsionStiffness = 0.2;
-                  psb->setSpringStiffness(repulsionStiffness);
-                  psb->initializeFaceTree();
-              }
-              //        psb->scale(btVector3(1, 1, 1));
-              psb->rotate(btQuaternion(btVector3(1, 0, 0), SIMD_PI * 0.5));
-              psb->translate(btVector3(0,1,0));
-              
-              psb->getCollisionShape()->setMargin(0.005);
-              psb->getCollisionShape()->setUserPointer(psb);
-              
-              psb->m_cfg.kKHR = 1; // collision hardness with kinematic objects
-              psb->m_cfg.kCHR = 1; // collision hardness with rigid body
-              getDeformableDynamicsWorld()->addSoftBody(psb);
-          
+        getDeformableDynamicsWorld()->addForce(psb, new btDeformableMassSpringForce(0.05,0.005, true));
+        getDeformableDynamicsWorld()->addForce(psb, new btDeformableGravityForce(gravity*0.1));
     }
     
 	m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld);
diff --git a/src/BulletSoftBody/btConjugateResidual.h b/src/BulletSoftBody/btConjugateResidual.h
index 4e01bb2f5..614612036 100644
--- a/src/BulletSoftBody/btConjugateResidual.h
+++ b/src/BulletSoftBody/btConjugateResidual.h
@@ -39,7 +39,6 @@ public:
 	// return the number of iterations taken
 	int solve(MatrixX& A, TVStack& x, const TVStack& b, bool verbose = false)
 	{
-        verbose = true;
 		BT_PROFILE("CRSolve");
 		btAssert(x.size() == b.size());
 		reinitialize(b);
diff --git a/src/BulletSoftBody/btDeformableBackwardEulerObjective.cpp b/src/BulletSoftBody/btDeformableBackwardEulerObjective.cpp
index 4a36e6617..0c3e0b5eb 100644
--- a/src/BulletSoftBody/btDeformableBackwardEulerObjective.cpp
+++ b/src/BulletSoftBody/btDeformableBackwardEulerObjective.cpp
@@ -18,7 +18,7 @@
 #include "LinearMath/btQuickprof.h"
 
 btDeformableBackwardEulerObjective::btDeformableBackwardEulerObjective(btAlignedObjectArray<btSoftBody*>& softBodies, const TVStack& backup_v)
-	: m_softBodies(softBodies), m_projection(softBodies, backup_v), m_backupVelocity(backup_v), m_implicit(false)
+	: m_softBodies(softBodies), m_projection(softBodies), m_backupVelocity(backup_v), m_implicit(false)
 {
 	m_massPreconditioner = new MassPreconditioner(m_softBodies);
 	m_KKTPreconditioner = new KKTPreconditioner(m_softBodies, m_projection, m_lf, m_dt, m_implicit);
diff --git a/src/BulletSoftBody/btDeformableBodySolver.cpp b/src/BulletSoftBody/btDeformableBodySolver.cpp
index 2d5537f49..139d69c7d 100644
--- a/src/BulletSoftBody/btDeformableBodySolver.cpp
+++ b/src/BulletSoftBody/btDeformableBodySolver.cpp
@@ -32,17 +32,6 @@ btDeformableBodySolver::~btDeformableBodySolver()
 
 void btDeformableBodySolver::solveDeformableConstraints(btScalar solverdt)
 {
-//    std::cout <<"before solve deformable constraints "<<std::endl;
-    btSoftBody* psb = m_softBodies[0];
-    for(int i = 0; i<psb->m_faces.size(); i++){
-//        std::cout<<"face "<<i<<": ";
-        const btSoftBody::Face& face =psb->m_faces[i];
-        btVector3 vel = btVector3(0,0,0);
-        for(int j = 0; j<3; j++){
-            vel+= face.m_n[j]->m_v* face.m_pcontact[j];
-        }
-//        std::cout<<vel[0]<<" "<<vel[1]<<" "<<vel[2]<<std::endl;
-    }
 	BT_PROFILE("solveDeformableConstraints");
 	if (!m_implicit)
 	{
@@ -59,25 +48,12 @@ void btDeformableBodySolver::solveDeformableConstraints(btScalar solverdt)
 			m_objective->addLagrangeMultiplier(m_dv, x);
 			m_objective->m_preconditioner->reinitialize(true);
 			computeStep(x, rhs);
-            m_objective->m_projection.checkConstraints(x);
 			for (int i = 0; i < m_dv.size(); ++i)
 			{
 				m_dv[i] = x[i];
 			}
 		}
 		updateVelocity();
-        
-//        std::cout <<"after solve deformable constraints "<<std::endl;
-        btSoftBody* psb = m_softBodies[0];
-        for(int i = 0; i<psb->m_faces.size(); i++){
-//            std::cout<<"face "<<i<<": ";
-            const btSoftBody::Face& face =psb->m_faces[i];
-            btVector3 vel = btVector3(0,0,0);
-            for(int j = 0; j<3; j++){
-                vel+=face.m_n[j]->m_v* face.m_pcontact[j];
-            }
-//            std::cout<<vel[0]<<" "<<vel[1]<<" "<<vel[2]<<std::endl;
-        }
 	}
 	else
 	{
@@ -306,11 +282,7 @@ void btDeformableBodySolver::updateVelocity()
 			}
 			else
 			{
-				psb->m_nodes[j].m_v = m_backupVelocity[counter] + m_dv[counter] - psb->m_nodes[j].m_splitv;
-//                std::cout<<"node "<<j<<", back up vel "<< m_backupVelocity[counter][0] <<" "<< m_backupVelocity[counter][1]<<" "<<m_backupVelocity[counter][2]<<std::endl;
-//                std::cout<<" , dv: "<< m_dv[counter][0]<<" "<< m_dv[counter][1]<<" "<< m_dv[counter][2]<<" "<<std::endl;
-//                std::cout<<", split v: "<<psb->m_nodes[j].m_splitv[0]<<" "<<psb->m_nodes[j].m_splitv[1]<<" "<<psb->m_nodes[j].m_splitv[2]<<" "<<std::endl;
-                
+				psb->m_nodes[j].m_v = m_backupVelocity[counter] + m_dv[counter] - psb->m_nodes[j].m_splitv;                
 			}
 			psb->m_maxSpeedSquared = btMax(psb->m_maxSpeedSquared, psb->m_nodes[j].m_v.length2());
 			++counter;
diff --git a/src/BulletSoftBody/btDeformableContactProjection.cpp b/src/BulletSoftBody/btDeformableContactProjection.cpp
index 6394eb9a2..733e648c4 100644
--- a/src/BulletSoftBody/btDeformableContactProjection.cpp
+++ b/src/BulletSoftBody/btDeformableContactProjection.cpp
@@ -495,8 +495,6 @@ void btDeformableContactProjection::setLagrangeMultiplier()
 			m_lagrangeMultipliers.push_back(lm);
 		}
         
-        
-        if( m_faceRigidConstraints[i].size()==0){
 		for (int j = 0; j < m_nodeRigidConstraints[i].size(); ++j)
 		{
 			if (!m_nodeRigidConstraints[i][j].m_binding)
@@ -523,7 +521,6 @@ void btDeformableContactProjection::setLagrangeMultiplier()
 			}
 			m_lagrangeMultipliers.push_back(lm);
         }            
-        }
         
 		for (int j = 0; j < m_faceRigidConstraints[i].size(); ++j)
 		{
@@ -536,16 +533,6 @@ void btDeformableContactProjection::setLagrangeMultiplier()
 			btVector3 bary = m_faceRigidConstraints[i][j].getContact()->m_bary;
 			LagrangeMultiplier lm;
 			lm.m_num_nodes = 3;
-            lm.m_vals[0] = lm.m_vals[1] = lm.m_vals[2] = 0;
-            
-            btVector3 face_vel = btVector3(0,0,0);
-            btVector3 backup_face_vel = btVector3(0,0,0);
-            for(int kk = 0; kk<3; kk++){
-                face_vel += (face->m_n[kk]->m_v + face->m_n[kk]->m_splitv)* bary[kk];
-                backup_face_vel += m_backupVelocity[face->m_n[kk]->index] * bary[kk];
-            }
-            
-            btVector3 dvel = face_vel - backup_face_vel;
             
 			for (int k = 0; k < 3; ++k)
 			{
@@ -560,16 +547,12 @@ void btDeformableContactProjection::setLagrangeMultiplier()
 				lm.m_dirs[0] = btVector3(1, 0, 0);
 				lm.m_dirs[1] = btVector3(0, 1, 0);
 				lm.m_dirs[2] = btVector3(0, 0, 1);
-                lm.m_vals[0] = dvel[0];
-                lm.m_vals[1] = dvel[1];
-                lm.m_vals[2] = dvel[2];
 			}
 			else
 			{
                 face->m_pcontact[3] = 0;
 				lm.m_num_constraints = 1;
 				lm.m_dirs[0] = m_faceRigidConstraints[i][j].m_normal;
-                lm.m_vals[0] = dvel.dot(m_faceRigidConstraints[i][j].m_normal);
 			}
 			m_lagrangeMultipliers.push_back(lm);
 		}
diff --git a/src/BulletSoftBody/btDeformableContactProjection.h b/src/BulletSoftBody/btDeformableContactProjection.h
index 82ae19ae6..4964eaf99 100644
--- a/src/BulletSoftBody/btDeformableContactProjection.h
+++ b/src/BulletSoftBody/btDeformableContactProjection.h
@@ -32,7 +32,6 @@ struct LagrangeMultiplier
 	btScalar m_weights[3];  // weights of the nodes involved, same size as m_num_nodes
 	btVector3 m_dirs[3];    // Constraint directions, same size of m_num_constraints;
 	int m_indices[3];       // indices of the nodes involved, same size as m_num_nodes;
-    btScalar m_vals[3];
 };
 
 class btDeformableContactProjection
@@ -40,7 +39,6 @@ class btDeformableContactProjection
 public:
 	typedef btAlignedObjectArray<btVector3> TVStack;
 	btAlignedObjectArray<btSoftBody*>& m_softBodies;
-    const TVStack& m_backupVelocity;
 
 	// all constraints involving face
 	btAlignedObjectArray<btDeformableContactConstraint*> m_allFaceConstraints;
@@ -66,8 +64,8 @@ public:
 
 	bool m_useStrainLimiting;
 
-	btDeformableContactProjection(btAlignedObjectArray<btSoftBody*>& softBodies, const TVStack& backupVelocity)
-		: m_softBodies(softBodies), m_backupVelocity(backupVelocity)
+	btDeformableContactProjection(btAlignedObjectArray<btSoftBody*>& softBodies)
+		: m_softBodies(softBodies)
 	{
 	}
 
diff --git a/src/BulletSoftBody/btSoftBody.cpp b/src/BulletSoftBody/btSoftBody.cpp
index 90f39db20..cca065afd 100644
--- a/src/BulletSoftBody/btSoftBody.cpp
+++ b/src/BulletSoftBody/btSoftBody.cpp
@@ -2860,6 +2860,7 @@ bool btSoftBody::checkDeformableFaceContact(const btCollisionObjectWrapper* colO
 	}
 #endif
 
+    // collision detection using x*
 	btTransform triangle_transform;
 	triangle_transform.setIdentity();
 	triangle_transform.setOrigin(f.m_n[0]->m_q);
@@ -2871,7 +2872,7 @@ bool btSoftBody::checkDeformableFaceContact(const btCollisionObjectWrapper* colO
 	if (dst >= 0)
 		return false;
 
-    // use the contact position of the previous collision
+    // Use consistent barycenter to recalculate distance.
     #ifdef CACHE_PREV_COLLISION
         if (f.m_pcontact[3] != 0)
         {
@@ -2881,37 +2882,22 @@ bool btSoftBody::checkDeformableFaceContact(const btCollisionObjectWrapper* colO
             const btConvexShape* csh = static_cast<const btConvexShape*>(shp);
             btGjkEpaSolver2::SignedDistance(contact_point, margin, csh, wtr,results);
             cti.m_colObj = colObjWrap->getCollisionObject();
-//            std::cout<<"****** distance1 "<<results.distance<<std::endl;
-//            std::cout<<"normal "<<results.normal[0]<<" "<<results.normal[1]<<" "<<results.normal[2]<<std::endl;
-//            std::cout<<"point is at "<<contact_point[0]<<" "<<contact_point[1]<<" "<<contact_point[2]<<std::endl;
-//            std::cout<<"three vertices: "<<std::endl;
-//            std::cout<<f.m_n[0]->m_x[0]<<" "<<f.m_n[0]->m_x[1]<<" "<<f.m_n[0]->m_x[2]<<" "<<std::endl;
-//            std::cout<<f.m_n[1]->m_x[0]<<" "<<f.m_n[1]->m_x[1]<<" "<<f.m_n[1]->m_x[2]<<" "<<std::endl;
-//            std::cout<<f.m_n[2]->m_x[0]<<" "<<f.m_n[2]->m_x[1]<<" "<<f.m_n[2]->m_x[2]<<" "<<std::endl;
             dst = results.distance;
             cti.m_normal = results.normal;
             cti.m_offset = dst;
-            
-            
-            // use face contact to redo collision detection
+        
+            //point-convex CD
             wtr = colObjWrap->getWorldTransform();
             btTriangleShape triangle2(btVector3(0, 0, 0), f.m_n[1]->m_x - f.m_n[0]->m_x, f.m_n[2]->m_x - f.m_n[0]->m_x);
             triangle_transform.setOrigin(f.m_n[0]->m_x);
             btGjkEpaSolver2::SignedDistance(&triangle2, triangle_transform, csh, wtr, guess, results);
             
             dst = results.distance - csh->getMargin() - margin;
-            
-//            std::cout<<"contact point 1 "<<results.witnesses[0][0]<< " "<<results.witnesses[0][1]<< " "<<results.witnesses[0][2]<< " "<<std::endl;
-//            std::cout<<"contact point 2 "<<results.witnesses[1][0]<< " "<<results.witnesses[1][1]<< " "<<results.witnesses[1][2]<< " "<<std::endl;
-//            std::cout<<"result distance  "<<results.distance<<std::endl;
-//            std::cout<< csh->getMargin() <<" "<<margin<<std::endl;
-//            std::cout<<"****** distance 2"<<dst<<std::endl;
-//            std::cout<<"normal "<< results.normal[0]<< " "<<results.normal[1]<< " "<<results.normal[2]<<std::endl;
             return true;
         }
     #endif
     
-    //
+    // Use triangle-convex CD.
 	wtr = colObjWrap->getWorldTransform();
 	btTriangleShape triangle2(btVector3(0, 0, 0), f.m_n[1]->m_x - f.m_n[0]->m_x, f.m_n[2]->m_x - f.m_n[0]->m_x);
 	triangle_transform.setOrigin(f.m_n[0]->m_x);
@@ -2923,18 +2909,12 @@ bool btSoftBody::checkDeformableFaceContact(const btCollisionObjectWrapper* colO
        f.m_pcontact[i] = bary[i];
     
 	dst = results.distance - csh->getMargin() - margin;
-    
-//    std::cout<<"contact point 1 "<<contact_point[0]<< " "<<contact_point[1]<< " "<<contact_point[2]<< " "<<std::endl;
-//    std::cout<<"contact point 2 "<<results.witnesses[1][0]<< " "<<results.witnesses[1][1]<< " "<<results.witnesses[1][2]<< " "<<std::endl;
-//    std::cout<<"result distance  "<<results.distance<<std::endl;
-//    std::cout<< csh->getMargin() <<" "<<margin<<std::endl;
-//    std::cout<<"distance "<<dst<<std::endl;
 	cti.m_colObj = colObjWrap->getCollisionObject();
 	cti.m_normal = results.normal;
 	cti.m_offset = dst;
 	return true;
 }
-//
+
 void btSoftBody::updateNormals()
 {
 	const btVector3 zv(0, 0, 0);
diff --git a/src/BulletSoftBody/btSoftBodyInternals.h b/src/BulletSoftBody/btSoftBodyInternals.h
index 81fd9bbca..62ec76769 100644
--- a/src/BulletSoftBody/btSoftBodyInternals.h
+++ b/src/BulletSoftBody/btSoftBodyInternals.h
@@ -1766,7 +1766,6 @@ struct btSoftColliders
 			btVector3 bary;
 			if (psb->checkDeformableFaceContact(m_colObj1Wrap, f, contact_point, bary, m, c.m_cti, true))
 			{
-//				f.m_pcontact[3] = 1;
 				btScalar ima = n0->m_im + n1->m_im + n2->m_im;
 				const btScalar imb = m_rigidBody ? m_rigidBody->getInvMass() : 0.f;
 				// todo: collision between multibody and fixed deformable face will be missed.
@@ -1839,11 +1838,8 @@ struct btSoftColliders
 					psb->m_faceRigidContacts.push_back(c);
 				}
 			}
-			else
-			{
-				f.m_pcontact[3] = 0;
-			}
-            //always mark caching contact as false
+            // Set caching barycenters to be false after collision detection.
+            // Only turn on when contact is static.
             f.m_pcontact[3] = 0;
 		}
 		btSoftBody* psb;