diff --git a/examples/SharedMemory/SharedMemoryCommands.h b/examples/SharedMemory/SharedMemoryCommands.h
index 958cf38a4..223a0a5d5 100644
--- a/examples/SharedMemory/SharedMemoryCommands.h
+++ b/examples/SharedMemory/SharedMemoryCommands.h
@@ -789,22 +789,6 @@ struct CalculateInverseKinematicsResultArgs
 	double m_jointPositions[MAX_DEGREE_OF_FREEDOM];
 };
 
-enum EnumUserConstraintFlags
-{
-	USER_CONSTRAINT_ADD_CONSTRAINT = 1,
-	USER_CONSTRAINT_REMOVE_CONSTRAINT = 2,
-	USER_CONSTRAINT_CHANGE_CONSTRAINT = 4,
-	USER_CONSTRAINT_CHANGE_PIVOT_IN_B = 8,
-	USER_CONSTRAINT_CHANGE_FRAME_ORN_IN_B = 16,
-	USER_CONSTRAINT_CHANGE_MAX_FORCE = 32,
-	USER_CONSTRAINT_REQUEST_INFO = 64,
-	USER_CONSTRAINT_CHANGE_GEAR_RATIO = 128,
-	USER_CONSTRAINT_CHANGE_GEAR_AUX_LINK = 256,
-	USER_CONSTRAINT_CHANGE_RELATIVE_POSITION_TARGET = 512,
-	USER_CONSTRAINT_CHANGE_ERP = 1024,
-	USER_CONSTRAINT_REQUEST_STATE = 2048,
-	USER_CONSTRAINT_ADD_SOFT_BODY_ANCHOR = 4096,
-};
 
 enum EnumBodyChangeFlags
 {
diff --git a/examples/SharedMemory/SharedMemoryPublic.h b/examples/SharedMemory/SharedMemoryPublic.h
index 01727fe5c..63a7cfa55 100644
--- a/examples/SharedMemory/SharedMemoryPublic.h
+++ b/examples/SharedMemory/SharedMemoryPublic.h
@@ -309,6 +309,23 @@ struct b3UserDataValue
 	const char* m_data1;
 };
 
+enum EnumUserConstraintFlags
+{
+	USER_CONSTRAINT_ADD_CONSTRAINT = 1,
+	USER_CONSTRAINT_REMOVE_CONSTRAINT = 2,
+	USER_CONSTRAINT_CHANGE_CONSTRAINT = 4,
+	USER_CONSTRAINT_CHANGE_PIVOT_IN_B = 8,
+	USER_CONSTRAINT_CHANGE_FRAME_ORN_IN_B = 16,
+	USER_CONSTRAINT_CHANGE_MAX_FORCE = 32,
+	USER_CONSTRAINT_REQUEST_INFO = 64,
+	USER_CONSTRAINT_CHANGE_GEAR_RATIO = 128,
+	USER_CONSTRAINT_CHANGE_GEAR_AUX_LINK = 256,
+	USER_CONSTRAINT_CHANGE_RELATIVE_POSITION_TARGET = 512,
+	USER_CONSTRAINT_CHANGE_ERP = 1024,
+	USER_CONSTRAINT_REQUEST_STATE = 2048,
+	USER_CONSTRAINT_ADD_SOFT_BODY_ANCHOR = 4096,
+};
+
 struct b3UserConstraint
 {
 	int m_parentBodyIndex;
diff --git a/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.cpp b/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.cpp
index 9f04cf6ce..4e81e599a 100644
--- a/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.cpp
+++ b/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.cpp
@@ -620,7 +620,7 @@ int b3RobotSimulatorClientAPI_NoDirect::createConstraint(int parentBodyIndex, in
 	return -1;
 }
 
-int b3RobotSimulatorClientAPI_NoDirect::changeConstraint(int constraintId, b3JointInfo* jointInfo)
+int b3RobotSimulatorClientAPI_NoDirect::changeConstraint(int constraintId, b3RobotUserConstraint* jointInfo)
 {
 	if (!isConnected())
 	{
@@ -629,16 +629,35 @@ int b3RobotSimulatorClientAPI_NoDirect::changeConstraint(int constraintId, b3Joi
 	}
 	b3SharedMemoryCommandHandle commandHandle = b3InitChangeUserConstraintCommand(m_data->m_physicsClientHandle, constraintId);
 
-	if (jointInfo->m_flags & eJointChangeMaxForce)
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_MAX_FORCE)
 	{
-		b3InitChangeUserConstraintSetMaxForce(commandHandle, jointInfo->m_jointMaxForce);
+		b3InitChangeUserConstraintSetMaxForce(commandHandle, jointInfo->m_maxAppliedForce);
 	}
 
-	if (jointInfo->m_flags & eJointChangeChildFramePosition)
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_GEAR_RATIO)
+	{
+		b3InitChangeUserConstraintSetGearRatio(commandHandle, jointInfo->m_gearRatio);
+	}
+
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_ERP)
+	{
+		b3InitChangeUserConstraintSetERP(commandHandle, jointInfo->m_erp);
+	}
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_GEAR_AUX_LINK)
+	{
+		b3InitChangeUserConstraintSetGearAuxLink(commandHandle, jointInfo->m_gearAuxLink);
+	}
+
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_RELATIVE_POSITION_TARGET)
+	{
+		b3InitChangeUserConstraintSetRelativePositionTarget(commandHandle, jointInfo->m_relativePositionTarget);
+	}
+	
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_PIVOT_IN_B)
 	{
 		b3InitChangeUserConstraintSetPivotInB(commandHandle, &jointInfo->m_childFrame[0]);
 	}
-	if (jointInfo->m_flags & eJointChangeChildFrameOrientation)
+	if (jointInfo->m_userUpdateFlags & USER_CONSTRAINT_CHANGE_FRAME_ORN_IN_B)
 	{
 		b3InitChangeUserConstraintSetFrameInB(commandHandle, &jointInfo->m_childFrame[3]);
 	}
diff --git a/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.h b/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.h
index c23a7af0d..78f729735 100644
--- a/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.h
+++ b/examples/SharedMemory/b3RobotSimulatorClientAPI_NoDirect.h
@@ -526,6 +526,100 @@ struct b3RobotSimulatorCreateMultiBodyArgs
 	}
 };
 
+
+struct b3RobotUserConstraint : public b3UserConstraint
+{
+	int m_userUpdateFlags;//see EnumUserConstraintFlags
+
+	void setErp(double erp)
+	{
+		m_erp = erp;
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_ERP;
+	}
+	
+	void setMaxAppliedForce(double maxForce)
+	{
+		m_maxAppliedForce = maxForce;
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_MAX_FORCE;
+	}
+	
+	void setGearRatio(double gearRatio)
+	{
+		m_gearRatio = gearRatio;
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_GEAR_RATIO;
+	}
+
+	void setGearAuxLink(int link)
+	{
+		m_gearAuxLink = link;
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_GEAR_AUX_LINK;
+	}
+
+	void setRelativePositionTarget(double target)
+	{
+		m_relativePositionTarget = target;
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_RELATIVE_POSITION_TARGET;
+	}
+
+	void setChildPivot(double pivot[3])
+	{
+		m_childFrame[0] = pivot[0];
+		m_childFrame[1] = pivot[1];
+		m_childFrame[2] = pivot[2];
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_PIVOT_IN_B;
+	}
+
+	void setChildFrameOrientation(double orn[4])
+	{
+		m_childFrame[3] = orn[0];
+		m_childFrame[4] = orn[1];
+		m_childFrame[5] = orn[2];
+		m_childFrame[6] = orn[3];
+		m_userUpdateFlags |= USER_CONSTRAINT_CHANGE_FRAME_ORN_IN_B;
+	}
+
+	b3RobotUserConstraint()
+		:m_userUpdateFlags(0)
+	{
+		m_parentBodyIndex = -1;
+		m_parentJointIndex = -1;
+		m_childBodyIndex = -1;
+		m_childJointIndex = -1;
+		//position
+		m_parentFrame[0] = 0;
+		m_parentFrame[1] = 0;
+		m_parentFrame[2] = 0;
+		//orientation quaternion [x,y,z,w]
+		m_parentFrame[3] = 0;
+		m_parentFrame[4] = 0;
+		m_parentFrame[5] = 0;
+		m_parentFrame[6] = 1;
+
+		//position
+		m_childFrame[0] = 0;
+		m_childFrame[1] = 0;
+		m_childFrame[2] = 0;
+		//orientation quaternion [x,y,z,w]
+		m_childFrame[3] = 0;
+		m_childFrame[4] = 0;
+		m_childFrame[5] = 0;
+		m_childFrame[6] = 1;
+
+		m_jointAxis[0] = 0;
+		m_jointAxis[1] = 0;
+		m_jointAxis[2] = 1;
+
+		m_jointType = eFixedType;
+
+		m_maxAppliedForce = 500;
+		m_userConstraintUniqueId = -1;
+		m_gearRatio = -1;
+		m_gearAuxLink = -1;
+		m_relativePositionTarget = 0;
+		m_erp = 0;
+	}
+};
+
 struct b3RobotJointInfo : public b3JointInfo
 {
 	b3RobotJointInfo()
@@ -624,7 +718,7 @@ public:
 
 	int createConstraint(int parentBodyIndex, int parentJointIndex, int childBodyIndex, int childJointIndex, b3JointInfo *jointInfo);
 
-	int changeConstraint(int constraintId, b3JointInfo *jointInfo);
+	int changeConstraint(int constraintId, b3RobotUserConstraint*jointInfo);
 
 	void removeConstraint(int constraintId);