public BSConstraintHinge(BulletWorld world, BulletBody obj1, BulletBody obj2,
     Vector3 pivotInA, Vector3 pivotInB,
     Vector3 axisInA, Vector3 axisInB,
     bool useLinearReferenceFrameA, bool disableCollisionsBetweenLinkedBodies)
     : base(world)
 {
     m_body1 = obj1;
     m_body2 = obj2;
     m_constraint = PhysicsScene.PE.CreateHingeConstraint(world, obj1, obj2,
         pivotInA, pivotInB, axisInA, axisInB,
         useLinearReferenceFrameA, disableCollisionsBetweenLinkedBodies);
     m_enabled = true;
 }

 // Create a btGeneric6DofConstraint
 public BSConstraint6Dof(BulletWorld world, BulletBody obj1, BulletBody obj2,
     Vector3 frame1, Quaternion frame1rot,
     Vector3 frame2, Quaternion frame2rot,
     bool useLinearReferenceFrameA, bool disableCollisionsBetweenLinkedBodies)
     : base(world)
 {
     m_body1 = obj1;
     m_body2 = obj2;
     m_constraint = PhysicsScene.PE.Create6DofConstraint(m_world, m_body1, m_body2,
         frame1, frame1rot,
         frame2, frame2rot,
         useLinearReferenceFrameA, disableCollisionsBetweenLinkedBodies);
     m_enabled = true;
     world.physicsScene.DetailLog(
         "{0},BS6DofConstraint,createFrame,wID={1}, rID={2}, rBody={3}, cID={4}, cBody={5}",
         BSScene.DetailLogZero, world.worldID,
         obj1.ID, obj1.AddrString, obj2.ID, obj2.AddrString);
 }

 // Remove all constraints that reference the passed body.
 // Return 'true' if any constraints were destroyed.
 public bool RemoveAndDestroyConstraint(BulletBody body1)
 {
     List<BSConstraint> toRemove = new List<BSConstraint>();
     uint lookingID = body1.ID;
     lock (m_constraints)
     {
         foreach (BSConstraint constrain in m_constraints)
         {
             if (constrain.Body1.ID == lookingID || constrain.Body2.ID == lookingID)
             {
                 toRemove.Add(constrain);
             }
         }
         foreach (BSConstraint constrain in toRemove)
         {
             m_constraints.Remove(constrain);
             constrain.Dispose();
         }
     }
     return (toRemove.Count > 0);
 }

 public abstract bool WantsSleeping(BulletBody obj);

 public abstract void UpdateInertiaTensor(BulletBody obj);

 public abstract void Translate(BulletBody obj, Vector3 trans);

 public abstract void SetTranslation(BulletBody obj, Vector3 position, Quaternion rotation);

 public abstract void SetRestitution(BulletBody obj, float val);

 public abstract void SetGravity(BulletBody obj, Vector3 val);

 public abstract void SetDeactivationTime(BulletBody obj, float dtime);

 public abstract void SetDamping(BulletBody obj, float lin_damping, float ang_damping);

 public abstract void SetContactProcessingThreshold(BulletBody obj, float val);

 public abstract void SetCollisionShape(BulletWorld sim, BulletBody obj, BulletShape shape);

 public abstract bool SetCollisionGroupMask(BulletBody body, UInt32 filter, UInt32 mask);

 public abstract void SetMassProps(BulletBody obj, float mass, Vector3 inertia);

 // Set the force being applied to the object as if its mass is one.
 public abstract void SetObjectForce(BulletBody obj, Vector3 force);

 public abstract void SetHitFraction(BulletBody obj, float val);

 public abstract void SetSleepingThresholds(BulletBody obj, float lin_threshold, float ang_threshold);

 // public abstract IntPtr GetBroadphaseHandle(BulletBody obj);
 // public abstract void SetBroadphaseHandle(BulletBody obj, IntPtr handle);
 public abstract void SetInterpolationLinearVelocity(BulletBody obj, Vector3 vel);

 public abstract void SetUserPointer(BulletBody obj, IntPtr val);