diff --git a/Demos/Benchmarks/BenchmarkDemo.cpp b/Demos/Benchmarks/BenchmarkDemo.cpp
index 979dc5e0c..3a1955f81 100644
--- a/Demos/Benchmarks/BenchmarkDemo.cpp
+++ b/Demos/Benchmarks/BenchmarkDemo.cpp
@@ -713,7 +713,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,M_PI_2); localA.setOrigin(scale*btVector3(btScalar(0.), btScalar(0.30), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_2); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(-0.14), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_2); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(-0.14), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_SPINE], *m_bodies[BODYPART_HEAD], localA, localB);
 		coneC->setLimit(M_PI_4, M_PI_4, M_PI_2);
 		m_joints[JOINT_SPINE_HEAD] = coneC;
@@ -722,7 +722,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,-M_PI_4*5); localA.setOrigin(scale*btVector3(btScalar(-0.18), btScalar(-0.10), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,M_PI_4*5); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,-M_PI_4*5); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_PELVIS], *m_bodies[BODYPART_LEFT_UPPER_LEG], localA, localB);
 		coneC->setLimit(M_PI_4, M_PI_4, 0);
 		m_joints[JOINT_LEFT_HIP] = coneC;
@@ -739,7 +739,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,M_PI_4); localA.setOrigin(scale*btVector3(btScalar(0.18), btScalar(-0.10), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_4); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_4); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_PELVIS], *m_bodies[BODYPART_RIGHT_UPPER_LEG], localA, localB);
 		coneC->setLimit(M_PI_4, M_PI_4, 0);
 		m_joints[JOINT_RIGHT_HIP] = coneC;
@@ -756,7 +756,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,M_PI); localA.setOrigin(scale*btVector3(btScalar(-0.2), btScalar(0.15), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_2); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_2); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_SPINE], *m_bodies[BODYPART_LEFT_UPPER_ARM], localA, localB);
 		coneC->setLimit(M_PI_2, M_PI_2, 0);
 		m_joints[JOINT_LEFT_SHOULDER] = coneC;
@@ -774,7 +774,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,0); localA.setOrigin(scale*btVector3(btScalar(0.2), btScalar(0.15), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_2); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_2); localB.setOrigin(scale*btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_SPINE], *m_bodies[BODYPART_RIGHT_UPPER_ARM], localA, localB);
 		coneC->setLimit(M_PI_2, M_PI_2, 0);
 		m_joints[JOINT_RIGHT_SHOULDER] = coneC;
@@ -1181,3 +1181,4 @@ void	BenchmarkDemo::exitPhysics()
 
 
 
+
diff --git a/Demos/RagdollDemo/RagdollDemo.cpp b/Demos/RagdollDemo/RagdollDemo.cpp
index 7f095e29e..6f90a53fc 100644
--- a/Demos/RagdollDemo/RagdollDemo.cpp
+++ b/Demos/RagdollDemo/RagdollDemo.cpp
@@ -202,7 +202,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,M_PI_2); localA.setOrigin(btVector3(btScalar(0.), btScalar(0.30), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_2); localB.setOrigin(btVector3(btScalar(0.), btScalar(-0.14), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_2); localB.setOrigin(btVector3(btScalar(0.), btScalar(-0.14), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_SPINE], *m_bodies[BODYPART_HEAD], localA, localB);
 		coneC->setLimit(M_PI_4, M_PI_4, M_PI_2);
 		m_joints[JOINT_SPINE_HEAD] = coneC;
@@ -211,7 +211,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,-M_PI_4*5); localA.setOrigin(btVector3(btScalar(-0.18), btScalar(-0.10), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,M_PI_4*5); localB.setOrigin(btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,-M_PI_4*5); localB.setOrigin(btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_PELVIS], *m_bodies[BODYPART_LEFT_UPPER_LEG], localA, localB);
 		coneC->setLimit(M_PI_4, M_PI_4, 0);
 		m_joints[JOINT_LEFT_HIP] = coneC;
@@ -228,7 +228,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,M_PI_4); localA.setOrigin(btVector3(btScalar(0.18), btScalar(-0.10), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_4); localB.setOrigin(btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_4); localB.setOrigin(btVector3(btScalar(0.), btScalar(0.225), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_PELVIS], *m_bodies[BODYPART_RIGHT_UPPER_LEG], localA, localB);
 		coneC->setLimit(M_PI_4, M_PI_4, 0);
 		m_joints[JOINT_RIGHT_HIP] = coneC;
@@ -245,7 +245,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,M_PI); localA.setOrigin(btVector3(btScalar(-0.2), btScalar(0.15), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_2); localB.setOrigin(btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_2); localB.setOrigin(btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_SPINE], *m_bodies[BODYPART_LEFT_UPPER_ARM], localA, localB);
 		coneC->setLimit(M_PI_2, M_PI_2, 0);
 		m_joints[JOINT_LEFT_SHOULDER] = coneC;
@@ -263,7 +263,7 @@ public:
 
 		localA.setIdentity(); localB.setIdentity();
 		localA.getBasis().setEulerZYX(0,0,0); localA.setOrigin(btVector3(btScalar(0.2), btScalar(0.15), btScalar(0.)));
-		localB.getBasis().setEulerZYX(0,0,-M_PI_2); localB.setOrigin(btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
+		localB.getBasis().setEulerZYX(0,0,M_PI_2); localB.setOrigin(btVector3(btScalar(0.), btScalar(-0.18), btScalar(0.)));
 		coneC = new btConeTwistConstraint(*m_bodies[BODYPART_SPINE], *m_bodies[BODYPART_RIGHT_UPPER_ARM], localA, localB);
 		coneC->setLimit(M_PI_2, M_PI_2, 0);
 		m_joints[JOINT_RIGHT_SHOULDER] = coneC;
@@ -468,3 +468,4 @@ void	RagdollDemo::exitPhysics()
 
 
 
+
diff --git a/src/BulletDynamics/ConstraintSolver/btConeTwistConstraint.cpp b/src/BulletDynamics/ConstraintSolver/btConeTwistConstraint.cpp
index a8a2c4f67..e11b49d94 100644
--- a/src/BulletDynamics/ConstraintSolver/btConeTwistConstraint.cpp
+++ b/src/BulletDynamics/ConstraintSolver/btConeTwistConstraint.cpp
@@ -33,11 +33,6 @@ btConeTwistConstraint::btConeTwistConstraint(btRigidBody& rbA,btRigidBody& rbB,
 											 :btTypedConstraint(CONETWIST_CONSTRAINT_TYPE, rbA,rbB),m_rbAFrame(rbAFrame),m_rbBFrame(rbBFrame),
 											 m_angularOnly(false)
 {
-	// flip axis for correct angles
-	m_rbBFrame.getBasis()[1][0] *= btScalar(-1.);
-	m_rbBFrame.getBasis()[1][1] *= btScalar(-1.);
-	m_rbBFrame.getBasis()[1][2] *= btScalar(-1.);
-
 	m_swingSpan1 = btScalar(1e30);
 	m_swingSpan2 = btScalar(1e30);
 	m_twistSpan  = btScalar(1e30);
@@ -55,15 +50,6 @@ btConeTwistConstraint::btConeTwistConstraint(btRigidBody& rbA,const btTransform&
 {
 	m_rbBFrame = m_rbAFrame;
 	
-	// flip axis for correct angles
-	m_rbBFrame.getBasis()[1][0] *= btScalar(-1.);
-	m_rbBFrame.getBasis()[1][1] *= btScalar(-1.);
-	m_rbBFrame.getBasis()[1][2] *= btScalar(-1.);
-
-	m_rbBFrame.getBasis()[2][0] *= btScalar(-1.);
-	m_rbBFrame.getBasis()[2][1] *= btScalar(-1.);
-	m_rbBFrame.getBasis()[2][2] *= btScalar(-1.);
-	
 	m_swingSpan1 = btScalar(1e30);
 	m_swingSpan2 = btScalar(1e30);
 	m_twistSpan  = btScalar(1e30);
@@ -143,7 +129,7 @@ void	btConeTwistConstraint::buildJacobian()
 
 	btScalar RMaxAngle1Sq = 1.0f / (m_swingSpan1*m_swingSpan1);		
 	btScalar RMaxAngle2Sq = 1.0f / (m_swingSpan2*m_swingSpan2);	
-	btScalar EllipseAngle = btFabs(swing1)* RMaxAngle1Sq + btFabs(swing2) * RMaxAngle2Sq;
+	btScalar EllipseAngle = btFabs(swing1*swing1)* RMaxAngle1Sq + btFabs(swing2*swing2) * RMaxAngle2Sq;
 
 	if (EllipseAngle > 1.0f)
 	{
diff --git a/src/LinearMath/btQuaternion.h b/src/LinearMath/btQuaternion.h
index 27ab1fcd2..2d1e79b9c 100644
--- a/src/LinearMath/btQuaternion.h
+++ b/src/LinearMath/btQuaternion.h
@@ -158,7 +158,7 @@ public:
 
 	btQuaternion inverse() const
 	{
-		return btQuaternion(m_x, m_y, m_z, -m_unusedW);
+		return btQuaternion(-m_x, -m_y, -m_z, m_unusedW);
 	}
 
 	SIMD_FORCE_INLINE btQuaternion
@@ -319,3 +319,4 @@ shortestArcQuatNormalize2(btVector3& v0,btVector3& v1)
 
 
 
+