10 files changed, 534 insertions, 390 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs b/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
index 623ac8f..a041ba8 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
@@ -105,7 +105,7 @@ public class BSCharacter : BSPhysObject
         shapeData.Position = _position;
         shapeData.Rotation = _orientation;
         shapeData.Velocity = _velocity;
-        shapeData.Size = Scale;
+        shapeData.Size = Scale; // capsule is a native shape but scale is not just <1,1,1>
         shapeData.Scale = Scale;
         shapeData.Mass = _mass;
         shapeData.Buoyancy = _buoyancy;
@@ -144,7 +144,9 @@ public class BSCharacter : BSPhysObject
         ForcePosition = _position;
         // Set the velocity and compute the proper friction
         ForceVelocity = _velocity;
+
         BulletSimAPI.SetRestitution2(BSBody.ptr, PhysicsScene.Params.avatarRestitution);
+        BulletSimAPI.SetMargin2(BSShape.ptr, PhysicsScene.Params.collisionMargin);
         BulletSimAPI.SetLocalScaling2(BSShape.ptr, Scale);
         BulletSimAPI.SetContactProcessingThreshold2(BSBody.ptr, PhysicsScene.Params.contactProcessingThreshold);
         if (PhysicsScene.Params.ccdMotionThreshold > 0f)
@@ -156,16 +158,20 @@ public class BSCharacter : BSPhysObject
         OMV.Vector3 localInertia = BulletSimAPI.CalculateLocalInertia2(BSShape.ptr, MassRaw);
         BulletSimAPI.SetMassProps2(BSBody.ptr, MassRaw, localInertia);
 
+        // Make so capsule does not fall over
+        BulletSimAPI.SetAngularFactorV2(BSBody.ptr, OMV.Vector3.Zero);
+
         BulletSimAPI.AddToCollisionFlags2(BSBody.ptr, CollisionFlags.CF_CHARACTER_OBJECT);
 
         BulletSimAPI.AddObjectToWorld2(PhysicsScene.World.ptr, BSBody.ptr);
 
-        BulletSimAPI.ForceActivationState2(BSBody.ptr, ActivationState.ACTIVE_TAG);
+        // BulletSimAPI.ForceActivationState2(BSBody.ptr, ActivationState.ACTIVE_TAG);
+        BulletSimAPI.ForceActivationState2(BSBody.ptr, ActivationState.DISABLE_DEACTIVATION);
         BulletSimAPI.UpdateSingleAabb2(PhysicsScene.World.ptr, BSBody.ptr);
 
         // Do this after the object has been added to the world
         BulletSimAPI.SetCollisionFilterMask2(BSBody.ptr,
-                        (uint)CollisionFilterGroups.AvatarFilter, 
+                        (uint)CollisionFilterGroups.AvatarFilter,
                         (uint)CollisionFilterGroups.AvatarMask);
     }
 
@@ -175,11 +181,13 @@ public class BSCharacter : BSPhysObject
     }
     // No one calls this method so I don't know what it could possibly mean
     public override bool Stopped { get { return false; } }
+
     public override OMV.Vector3 Size {
         get
         {
             // Avatar capsule size is kept in the scale parameter.
-            return _size;
+            // return _size;
+            return new OMV.Vector3(Scale.X * 2f, Scale.Y * 2f, Scale.Z);
         }
 
         set {
@@ -199,7 +207,9 @@ public class BSCharacter : BSPhysObject
 
         }
     }
+
     public override OMV.Vector3 Scale { get; set; }
+
     public override PrimitiveBaseShape Shape
     {
         set { BaseShape = value; }
@@ -264,12 +274,12 @@ public class BSCharacter : BSPhysObject
 
 
     // Check that the current position is sane and, if not, modify the position to make it so.
-    // Check for being below terrain and being out of bounds.
+    // Check for being below terrain or on water.
     // Returns 'true' of the position was made sane by some action.
     private bool PositionSanityCheck()
     {
         bool ret = false;
-      
+
         // If below the ground, move the avatar up
         float terrainHeight = PhysicsScene.TerrainManager.GetTerrainHeightAtXYZ(_position);
         if (Position.Z < terrainHeight)
@@ -335,7 +345,7 @@ public class BSCharacter : BSPhysObject
     }
 
     // Avatars don't do vehicles
-    public override int VehicleType { get { return 0; } set { return; } }
+    public override int VehicleType { get { return (int)Vehicle.TYPE_NONE; } set { return; } }
     public override void VehicleFloatParam(int param, float value) { }
     public override void VehicleVectorParam(int param, OMV.Vector3 value) {}
     public override void VehicleRotationParam(int param, OMV.Quaternion rotation) { }
@@ -413,7 +423,7 @@ public class BSCharacter : BSPhysObject
             });
         }
     }
-    // Go directly to Bullet to get/set the value. 
+    // Go directly to Bullet to get/set the value.
     public override OMV.Quaternion ForceOrientation
     {
         get
@@ -478,7 +488,7 @@ public class BSCharacter : BSPhysObject
         set { _collidingObj = value; }
     }
     public override bool FloatOnWater {
-        set { 
+        set {
             _floatOnWater = value;
             PhysicsScene.TaintedObject("BSCharacter.setFloatOnWater", delegate()
             {
@@ -588,9 +598,8 @@ public class BSCharacter : BSPhysObject
         newScale.X = PhysicsScene.Params.avatarCapsuleRadius;
         newScale.Y = PhysicsScene.Params.avatarCapsuleRadius;
 
-        // From the total height, remote the capsule half spheres that are at each end 
-        newScale.Z = (size.Z * 2f) - Math.Min(newScale.X, newScale.Y);
-        // newScale.Z = (size.Z * 2f);
+        // From the total height, remove the capsule half spheres that are at each end
+        newScale.Z = size.Z- (newScale.X + newScale.Y);
         Scale = newScale;
     }
 
@@ -636,7 +645,7 @@ public class BSCharacter : BSPhysObject
             BulletSimAPI.SetLinearVelocity2(BSBody.ptr, avVel);
         }
 
-        // Tell the linkset about this
+        // Tell the linkset about value changes
         Linkset.UpdateProperties(this);
 
         // Avatars don't report their changes the usual way. Changes are checked for in the heartbeat loop.
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs b/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs
index a20be3a..f017cdd 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs
@@ -34,6 +34,8 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
 public abstract class BSConstraint : IDisposable
 {
+    private static string LogHeader = "[BULLETSIM CONSTRAINT]";
+
     protected BulletSim m_world;
     protected BulletBody m_body1;
     protected BulletBody m_body2;
@@ -53,7 +55,7 @@ public abstract class BSConstraint : IDisposable
             {
                 bool success = BulletSimAPI.DestroyConstraint2(m_world.ptr, m_constraint.ptr);
                 m_world.physicsScene.DetailLog("{0},BSConstraint.Dispose,taint,id1={1},body1={2},id2={3},body2={4},success={5}",
-                                    BSScene.DetailLogZero, 
+                                    BSScene.DetailLogZero,
                                     m_body1.ID, m_body1.ptr.ToString("X"),
                                     m_body2.ID, m_body2.ptr.ToString("X"),
                                     success);
@@ -124,7 +126,7 @@ public abstract class BSConstraint : IDisposable
             }
             else
             {
-                m_world.physicsScene.Logger.ErrorFormat("[BULLETSIM CONSTRAINT] CalculateTransforms failed. A={0}, B={1}", Body1.ID, Body2.ID);
+                m_world.physicsScene.Logger.ErrorFormat("{0} CalculateTransforms failed. A={1}, B={2}", LogHeader, Body1.ID, Body2.ID);
             }
         }
         return ret;
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
index 56342b8..117c878 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
@@ -23,7 +23,7 @@
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
+ *
 
 /* RA: June 14, 2011. Copied from ODEDynamics.cs and converted to
  * call the BulletSim system.
@@ -352,7 +352,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     // m_bankingMix = 1;
                     // m_bankingTimescale = 1;
                     // m_referenceFrame = Quaternion.Identity;
-                    m_flags |= (VehicleFlag.NO_DEFLECTION_UP 
+                    m_flags |= (VehicleFlag.NO_DEFLECTION_UP
                                 | VehicleFlag.LIMIT_ROLL_ONLY
                                 | VehicleFlag.LIMIT_MOTOR_UP);
                     m_flags &= ~(VehicleFlag.HOVER_WATER_ONLY | VehicleFlag.HOVER_TERRAIN_ONLY | VehicleFlag.HOVER_GLOBAL_HEIGHT);
@@ -382,7 +382,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     // m_bankingTimescale = 1;
                     // m_referenceFrame = Quaternion.Identity;
                     m_flags &= ~(VehicleFlag.HOVER_TERRAIN_ONLY
-                                    | VehicleFlag.HOVER_GLOBAL_HEIGHT 
+                                    | VehicleFlag.HOVER_GLOBAL_HEIGHT
                                     | VehicleFlag.LIMIT_ROLL_ONLY
                                     | VehicleFlag.HOVER_UP_ONLY);
                     m_flags |= (VehicleFlag.NO_DEFLECTION_UP
@@ -458,14 +458,15 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         // Do any updating needed for a vehicle
         public void Refresh()
         {
-            if (!IsActive) 
+            if (!IsActive)
                 return;
 
             // Set the prim's inertia to zero. The vehicle code handles that and this
             //    removes the motion and torque actions introduced by Bullet.
             Vector3 inertia = Vector3.Zero;
-            BulletSimAPI.SetMassProps2(Prim.BSBody.ptr, Prim.MassRaw, inertia);
-            BulletSimAPI.UpdateInertiaTensor2(Prim.BSBody.ptr);
+            // comment out for DEBUG test
+            // BulletSimAPI.SetMassProps2(Prim.BSBody.ptr, Prim.MassRaw, inertia);
+            // BulletSimAPI.UpdateInertiaTensor2(Prim.BSBody.ptr);
         }
 
         // One step of the vehicle properties for the next 'pTimestep' seconds.
@@ -791,7 +792,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
             // Sum velocities
             m_lastAngularVelocity = m_angularMotorVelocity + vertattr; // + bank + deflection
-         
+
             if ((m_flags & (VehicleFlag.NO_DEFLECTION_UP)) != 0)
             {
                 m_lastAngularVelocity.X = 0;
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
index 43b1262..c984824 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
@@ -32,10 +32,27 @@ using OMV = OpenMetaverse;
 
 namespace OpenSim.Region.Physics.BulletSPlugin
 {
-public class BSLinkset
+public abstract class BSLinkset
 {
     // private static string LogHeader = "[BULLETSIM LINKSET]";
 
+    // Create the correct type of linkset for this child
+    public static BSLinkset Factory(BSScene physScene, BSPhysObject parent)
+    {
+        BSLinkset ret = null;
+        /*
+        if (parent.IsPhysical)
+            ret = new BSLinksetConstraints(physScene, parent);
+        else
+            ret = new BSLinksetManual(physScene, parent);
+         */
+
+        // at the moment, there is only one
+        ret = new BSLinksetConstraints(physScene, parent);
+
+        return ret;
+    }
+
     public BSPhysObject LinksetRoot { get; protected set; }
 
     public BSScene PhysicsScene { get; private set; }
@@ -52,16 +69,16 @@ public class BSLinkset
     //    the physical 'taint' children separately.
     // After taint processing and before the simulation step, these
     //    two lists must be the same.
-    private HashSet<BSPhysObject> m_children;
-    private HashSet<BSPhysObject> m_taintChildren;
+    protected HashSet<BSPhysObject> m_children;
+    protected HashSet<BSPhysObject> m_taintChildren;
 
     // We lock the diddling of linkset classes to prevent any badness.
     // This locks the modification of the instances of this class. Changes
     //    to the physical representation is done via the tainting mechenism.
-    private object m_linksetActivityLock = new Object();
+    protected object m_linksetActivityLock = new Object();
 
     // We keep the prim's mass in the linkset structure since it could be dependent on other prims
-    private float m_mass;
+    protected float m_mass;
     public float LinksetMass
     {
         get
@@ -81,7 +98,7 @@ public class BSLinkset
         get { return ComputeLinksetGeometricCenter(); }
     }
 
-    public BSLinkset(BSScene scene, BSPhysObject parent)
+    protected void Initialize(BSScene scene, BSPhysObject parent)
     {
         // A simple linkset of one (no children)
         LinksetID = m_nextLinksetID++;
@@ -128,7 +145,7 @@ public class BSLinkset
         }
 
         // The child is down to a linkset of just itself
-        return new BSLinkset(PhysicsScene, child);
+        return BSLinkset.Factory(PhysicsScene, child);
     }
 
     // Return 'true' if the passed object is the root object of this linkset
@@ -148,6 +165,9 @@ public class BSLinkset
         bool ret = false;
         lock (m_linksetActivityLock)
         {
+            if (m_children.Contains(child))
+                    ret = true;
+            /*
             foreach (BSPhysObject bp in m_children)
             {
                 if (child.LocalID == bp.LocalID)
@@ -156,6 +176,7 @@ public class BSLinkset
                     break;
                 }
             }
+             */
         }
         return ret;
     }
@@ -163,24 +184,7 @@ public class BSLinkset
     // When physical properties are changed the linkset needs to recalculate
     //   its internal properties.
     // May be called at runtime or taint-time (just pass the appropriate flag).
-    public void Refresh(BSPhysObject requestor, bool inTaintTime)
-    {
-        // If there are no children, not physical or not root, I am not the one that recomputes the constraints
-        // (For the moment, static linksets do create constraints so remove the test for physical.)
-        if (!HasAnyChildren || /*!requestor.IsPhysical ||*/ !IsRoot(requestor))
-            return;
-
-        BSScene.TaintCallback refreshOperation = delegate()
-            {
-                RecomputeLinksetConstraintVariables();
-                DetailLog("{0},BSLinkset.Refresh,complete,rBody={1}", 
-                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"));
-            };
-        if (inTaintTime)
-            refreshOperation();
-        else
-            PhysicsScene.TaintedObject("BSLinkSet.Refresh", refreshOperation);
-    }
+    public abstract void Refresh(BSPhysObject requestor, bool inTaintTime);
 
     // The object is going dynamic (physical). Do any setup necessary
     //     for a dynamic linkset.
@@ -188,102 +192,35 @@ public class BSLinkset
     //     has not yet been fully constructed.
     // Return 'true' if any properties updated on the passed object.
     // Called at taint-time!
-    public bool MakeDynamic(BSPhysObject child)
-    {
-        // What is done for each object in BSPrim is what we want.
-        return false;
-    }
+    public abstract bool MakeDynamic(BSPhysObject child);
 
     // The object is going static (non-physical). Do any setup necessary
     //     for a static linkset.
     // Return 'true' if any properties updated on the passed object.
     // Called at taint-time!
-    public bool MakeStatic(BSPhysObject child)
-    {
-        // What is done for each object in BSPrim is what we want.
-        return false;
-    }
+    public abstract bool MakeStatic(BSPhysObject child);
 
-    // If the software is handling the movement of all the objects in a linkset
-    // (like if one doesn't use constraints for static linksets), this is called
-    // when an update for the root of the linkset is received.
+    // Called when a parameter update comes from the physics engine for any object
+    //      of the linkset is received.
     // Called at taint-time!!
-    public void UpdateProperties(BSPhysObject physObject)
-    {
-        // The root local properties have been updated. Apply to the children if appropriate.
-        if (IsRoot(physObject) && HasAnyChildren)
-        {
-            if (!physObject.IsPhysical)
-            {
-                // TODO: implement software linkset update for static object linksets
-            }
-        }
-    }
+    public abstract void UpdateProperties(BSPhysObject physObject);
 
     // Routine used when rebuilding the body of the root of the linkset
     // Destroy all the constraints have have been made to root.
     // This is called when the root body is changing.
-    // Returns 'true' of something eas actually removed and would need restoring
+    // Returns 'true' of something was actually removed and would need restoring
     // Called at taint-time!!
-    public bool RemoveBodyDependencies(BSPrim child)
-    {
-        bool ret = false;
-
-        lock (m_linksetActivityLock)
-        {
-            if (IsRoot(child))
-            {
-                // If the one with the dependency is root, must undo all children
-                DetailLog("{0},BSLinkset.RemoveBodyDependencies,removeChildrenForRoot,rID={1},rBody={2}",
-                                                child.LocalID, LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"));
-
-                ret = PhysicallyUnlinkAllChildrenFromRoot(LinksetRoot);
-            }
-            else
-            {
-                DetailLog("{0},BSLinkset.RemoveBodyDependencies,removeSingleChild,rID={1},rBody={2},cID={3},cBody={4}",
-                                                child.LocalID,
-                                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"),
-                                                child.LocalID, child.BSBody.ptr.ToString("X"));
-                // ret = PhysicallyUnlinkAChildFromRoot(LinksetRoot, child);
-                // Despite the function name, this removes any link to the specified object.
-                ret = PhysicallyUnlinkAllChildrenFromRoot(child);
-            }
-        }
-        return ret;
-    }
+    public abstract bool RemoveBodyDependencies(BSPrim child);
 
     // Companion to RemoveBodyDependencies(). If RemoveBodyDependencies() returns 'true',
-    // this routine will restore the removed constraints.
+    //     this routine will restore the removed constraints.
     // Called at taint-time!!
-    public void RestoreBodyDependencies(BSPrim child)
-    {
-        lock (m_linksetActivityLock)
-        {
-            if (IsRoot(child))
-            {
-                DetailLog("{0},BSLinkset.RestoreBodyDependencies,restoreChildrenForRoot,rID={1},numChild={2}",
-                                                child.LocalID, LinksetRoot.LocalID, m_taintChildren.Count);
-                foreach (BSPhysObject bpo in m_taintChildren)
-                {
-                    PhysicallyLinkAChildToRoot(LinksetRoot, bpo);
-                }
-            }
-            else
-            {
-                DetailLog("{0},BSLinkset.RestoreBodyDependencies,restoreSingleChild,rID={1},rBody={2},cID={3},cBody={4}",
-                                                LinksetRoot.LocalID,
-                                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"),
-                                                child.LocalID, child.BSBody.ptr.ToString("X"));
-                PhysicallyLinkAChildToRoot(LinksetRoot, child);
-            }
-        }
-    }
+    public abstract void RestoreBodyDependencies(BSPrim child);
 
     // ================================================================
     // Below this point is internal magic
 
-    private float ComputeLinksetMass()
+    protected virtual float ComputeLinksetMass()
     {
         float mass;
         lock (m_linksetActivityLock)
@@ -297,7 +234,7 @@ public class BSLinkset
         return mass;
     }
 
-    private OMV.Vector3 ComputeLinksetCenterOfMass()
+    protected virtual OMV.Vector3 ComputeLinksetCenterOfMass()
     {
         OMV.Vector3 com;
         lock (m_linksetActivityLock)
@@ -317,7 +254,7 @@ public class BSLinkset
         return com;
     }
 
-    private OMV.Vector3 ComputeLinksetGeometricCenter()
+    protected virtual OMV.Vector3 ComputeLinksetGeometricCenter()
     {
         OMV.Vector3 com;
         lock (m_linksetActivityLock)
@@ -336,236 +273,21 @@ public class BSLinkset
 
     // I am the root of a linkset and a new child is being added
     // Called while LinkActivity is locked.
-    private void AddChildToLinkset(BSPhysObject child)
-    {
-        if (!HasChild(child))
-        {
-            m_children.Add(child);
-
-            BSPhysObject rootx = LinksetRoot; // capture the root as of now
-            BSPhysObject childx = child;
-
-            DetailLog("{0},AddChildToLinkset,call,child={1}", LinksetRoot.LocalID, child.LocalID);
-
-            PhysicsScene.TaintedObject("AddChildToLinkset", delegate()
-            {
-                DetailLog("{0},AddChildToLinkset,taint,rID={1},rBody={2},cID={3},cBody={4}", 
-                                rootx.LocalID,
-                                rootx.LocalID, rootx.BSBody.ptr.ToString("X"),
-                                childx.LocalID, childx.BSBody.ptr.ToString("X"));
-                // Since this is taint-time, the body and shape could have changed for the child
-                rootx.ForcePosition = rootx.Position;   // DEBUG
-                childx.ForcePosition = childx.Position;   // DEBUG
-                PhysicallyLinkAChildToRoot(rootx, childx);
-                m_taintChildren.Add(child);
-            });
-        }
-        return;
-    }
+    protected abstract void AddChildToLinkset(BSPhysObject child);
 
     // Forcefully removing a child from a linkset.
     // This is not being called by the child so we have to make sure the child doesn't think
     //    it's still connected to the linkset.
     // Normal OpenSimulator operation will never do this because other SceneObjectPart information
     //    also has to be updated (like pointer to prim's parent).
-    private void RemoveChildFromOtherLinkset(BSPhysObject pchild)
-    {
-        pchild.Linkset = new BSLinkset(PhysicsScene, pchild);
-        RemoveChildFromLinkset(pchild);
-    }
+    protected abstract void RemoveChildFromOtherLinkset(BSPhysObject pchild);
 
     // I am the root of a linkset and one of my children is being removed.
     // Safe to call even if the child is not really in my linkset.
-    private void RemoveChildFromLinkset(BSPhysObject child)
-    {
-        if (m_children.Remove(child))
-        {
-            BSPhysObject rootx = LinksetRoot; // capture the root and body as of now
-            BSPhysObject childx = child;
-
-            DetailLog("{0},RemoveChildFromLinkset,call,rID={1},rBody={2},cID={3},cBody={4}", 
-                            childx.LocalID,
-                            rootx.LocalID, rootx.BSBody.ptr.ToString("X"),
-                            childx.LocalID, childx.BSBody.ptr.ToString("X"));
-
-            PhysicsScene.TaintedObject("RemoveChildFromLinkset", delegate()
-            {
-                m_taintChildren.Remove(child);
-                PhysicallyUnlinkAChildFromRoot(rootx, childx);
-                RecomputeLinksetConstraintVariables();
-            });
-
-        }
-        else
-        {
-            // This will happen if we remove the root of the linkset first. Non-fatal occurance.
-            // PhysicsScene.Logger.ErrorFormat("{0}: Asked to remove child from linkset that was not in linkset", LogHeader);
-        }
-        return;
-    }
-
-    // Create a constraint between me (root of linkset) and the passed prim (the child).
-    // Called at taint time!
-    private void PhysicallyLinkAChildToRoot(BSPhysObject rootPrim, BSPhysObject childPrim)
-    {
-        // Zero motion for children so they don't interpolate
-        childPrim.ZeroMotion();
-
-        // Relative position normalized to the root prim
-        // Essentually a vector pointing from center of rootPrim to center of childPrim
-        OMV.Vector3 childRelativePosition = childPrim.Position - rootPrim.Position;
-
-        // real world coordinate of midpoint between the two objects
-        OMV.Vector3 midPoint = rootPrim.Position + (childRelativePosition / 2);
-
-        DetailLog("{0},BSLinkset.PhysicallyLinkAChildToRoot,taint,root={1},rBody={2},child={3},cBody={4},rLoc={5},cLoc={6},midLoc={7}",
-                                        rootPrim.LocalID,
-                                        rootPrim.LocalID, rootPrim.BSBody.ptr.ToString("X"),
-                                        childPrim.LocalID, childPrim.BSBody.ptr.ToString("X"),
-                                        rootPrim.Position, childPrim.Position, midPoint);
-
-        // create a constraint that allows no freedom of movement between the two objects
-        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
-
-        BS6DofConstraint constrain = new BS6DofConstraint(
-                            PhysicsScene.World, rootPrim.BSBody, childPrim.BSBody, midPoint, true, true );
-
-        /* NOTE: below is an attempt to build constraint with full frame computation, etc.
-         *     Using the midpoint is easier since it lets the Bullet code manipulate the transforms
-         *     of the objects.
-         * Code left as a warning to future programmers.
-        // ==================================================================================
-        // relative position normalized to the root prim
-        OMV.Quaternion invThisOrientation = OMV.Quaternion.Inverse(rootPrim.Orientation);
-        OMV.Vector3 childRelativePosition = (childPrim.Position - rootPrim.Position) * invThisOrientation;
-
-        // relative rotation of the child to the parent
-        OMV.Quaternion childRelativeRotation = invThisOrientation * childPrim.Orientation;
-        OMV.Quaternion inverseChildRelativeRotation = OMV.Quaternion.Inverse(childRelativeRotation);
-
-        // create a constraint that allows no freedom of movement between the two objects
-        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
-        DetailLog("{0},BSLinkset.PhysicallyLinkAChildToRoot,taint,root={1},child={2}", rootPrim.LocalID, rootPrim.LocalID, childPrim.LocalID);
-        BS6DofConstraint constrain = new BS6DofConstraint(
-                        PhysicsScene.World, rootPrim.Body, childPrim.Body,
-                        OMV.Vector3.Zero,
-                        OMV.Quaternion.Inverse(rootPrim.Orientation),
-                        OMV.Vector3.Zero,
-                        OMV.Quaternion.Inverse(childPrim.Orientation),
-                        // A point half way between the parent and child
-                        // childRelativePosition/2,
-                        // childRelativeRotation,
-                        // childRelativePosition/2,
-                        // inverseChildRelativeRotation,
-                        true,
-                        true
-                        );
-        // ==================================================================================
-        */
-
-        PhysicsScene.Constraints.AddConstraint(constrain);
-
-        // zero linear and angular limits makes the objects unable to move in relation to each other
-        constrain.SetLinearLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
-        constrain.SetAngularLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
-
-        // tweek the constraint to increase stability
-        constrain.UseFrameOffset(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintUseFrameOffset));
-        constrain.TranslationalLimitMotor(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintEnableTransMotor),
-                        PhysicsScene.Params.linkConstraintTransMotorMaxVel,
-                        PhysicsScene.Params.linkConstraintTransMotorMaxForce);
-        constrain.SetCFMAndERP(PhysicsScene.Params.linkConstraintCFM, PhysicsScene.Params.linkConstraintERP);
-        if (PhysicsScene.Params.linkConstraintSolverIterations != 0f)
-        {
-            constrain.SetSolverIterations(PhysicsScene.Params.linkConstraintSolverIterations);
-        }
-    }
-
-    // Remove linkage between myself and a particular child
-    // The root and child bodies are passed in because we need to remove the constraint between
-    //      the bodies that were at unlink time.
-    // Called at taint time!
-    private bool PhysicallyUnlinkAChildFromRoot(BSPhysObject rootPrim, BSPhysObject childPrim)
-    {
-        bool ret = false;
-        DetailLog("{0},BSLinkset.PhysicallyUnlinkAChildFromRoot,taint,root={1},rBody={2},child={3},cBody={4}",
-                            rootPrim.LocalID,
-                            rootPrim.LocalID, rootPrim.BSBody.ptr.ToString("X"),
-                            childPrim.LocalID, childPrim.BSBody.ptr.ToString("X"));
-
-        // Find the constraint for this link and get rid of it from the overall collection and from my list
-        if (PhysicsScene.Constraints.RemoveAndDestroyConstraint(rootPrim.BSBody, childPrim.BSBody))
-        {
-            // Make the child refresh its location
-            BulletSimAPI.PushUpdate2(childPrim.BSBody.ptr);
-            ret = true;
-        }
-
-        return ret;
-    }
-
-    // Remove linkage between myself and any possible children I might have.
-    // Called at taint time!
-    private bool PhysicallyUnlinkAllChildrenFromRoot(BSPhysObject rootPrim)
-    {
-        DetailLog("{0},BSLinkset.PhysicallyUnlinkAllChildren,taint", rootPrim.LocalID);
-        bool ret = false;
-
-        if (PhysicsScene.Constraints.RemoveAndDestroyConstraint(rootPrim.BSBody))
-        {
-            ret = true;
-        }
-        return ret;
-    }
-
-    // Call each of the constraints that make up this linkset and recompute the
-    //    various transforms and variables. Used when objects are added or removed
-    //    from a linkset to make sure the constraints know about the new mass and
-    //    geometry.
-    // Must only be called at taint time!!
-    private void RecomputeLinksetConstraintVariables()
-    {
-        float linksetMass = LinksetMass;
-        foreach (BSPhysObject child in m_taintChildren)
-        {
-            BSConstraint constrain;
-            if (PhysicsScene.Constraints.TryGetConstraint(LinksetRoot.BSBody, child.BSBody, out constrain))
-            {
-                // DetailLog("{0},BSLinkset.RecomputeLinksetConstraintVariables,taint,child={1},mass={2},A={3},B={4}",
-                //         LinksetRoot.LocalID, child.LocalID, linksetMass, constrain.Body1.ID, constrain.Body2.ID);
-                constrain.RecomputeConstraintVariables(linksetMass);
-            }
-            else
-            {
-                // Non-fatal error that happens when children are being added to the linkset but
-                //    their constraints have not been created yet.
-                break;
-            }
-        }
-
-        // If the whole linkset is not here, doesn't make sense to recompute linkset wide values
-        if (m_children.Count == m_taintChildren.Count)
-        {
-            // If this is a multiple object linkset, set everybody's center of mass to the set's center of mass
-            OMV.Vector3 centerOfMass = ComputeLinksetCenterOfMass();
-            BulletSimAPI.SetCenterOfMassByPosRot2(LinksetRoot.BSBody.ptr, 
-                                centerOfMass, OMV.Quaternion.Identity);
-            DetailLog("{0},BSLinkset.RecomputeLinksetConstraintVariables,setCenterOfMass,COM={1},rBody={2}",
-                                LinksetRoot.LocalID, centerOfMass, LinksetRoot.BSBody.ptr.ToString("X"));
-            foreach (BSPhysObject child in m_taintChildren)
-            {
-                BulletSimAPI.SetCenterOfMassByPosRot2(child.BSBody.ptr, 
-                                centerOfMass, OMV.Quaternion.Identity);
-            }
-
-            // BulletSimAPI.DumpAllInfo2(PhysicsScene.World.ptr);  // DEBUG DEBUG DEBUG
-        }
-        return;
-    }
-
+    protected abstract void RemoveChildFromLinkset(BSPhysObject child);
 
     // Invoke the detailed logger and output something if it's enabled.
-    private void DetailLog(string msg, params Object[] args)
+    protected void DetailLog(string msg, params Object[] args)
     {
         if (PhysicsScene.PhysicsLogging.Enabled)
             PhysicsScene.DetailLog(msg, args);
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinksetConstraints.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinksetConstraints.cs
new file mode 100755
index 0000000..8a750b5
--- /dev/null
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinksetConstraints.cs
@@ -0,0 +1,385 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyrightD
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using OMV = OpenMetaverse;
+
+namespace OpenSim.Region.Physics.BulletSPlugin
+{
+public class BSLinksetConstraints : BSLinkset
+{
+    // private static string LogHeader = "[BULLETSIM LINKSET CONSTRAINTS]";
+
+    public BSLinksetConstraints(BSScene scene, BSPhysObject parent)
+    {
+        base.Initialize(scene, parent);
+    }
+
+    // When physical properties are changed the linkset needs to recalculate
+    //   its internal properties.
+    // May be called at runtime or taint-time (just pass the appropriate flag).
+    public override void Refresh(BSPhysObject requestor, bool inTaintTime)
+    {
+        // If there are no children or not root, I am not the one that recomputes the constraints
+        if (!HasAnyChildren || !IsRoot(requestor))
+            return;
+
+        BSScene.TaintCallback refreshOperation = delegate()
+            {
+                RecomputeLinksetConstraintVariables();
+                DetailLog("{0},BSLinkset.Refresh,complete,rBody={1}",
+                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"));
+            };
+        if (inTaintTime)
+            refreshOperation();
+        else
+            PhysicsScene.TaintedObject("BSLinkSet.Refresh", refreshOperation);
+    }
+
+    // The object is going dynamic (physical). Do any setup necessary
+    //     for a dynamic linkset.
+    // Only the state of the passed object can be modified. The rest of the linkset
+    //     has not yet been fully constructed.
+    // Return 'true' if any properties updated on the passed object.
+    // Called at taint-time!
+    public override bool MakeDynamic(BSPhysObject child)
+    {
+        // What is done for each object in BSPrim is what we want.
+        return false;
+    }
+
+    // The object is going static (non-physical). Do any setup necessary
+    //     for a static linkset.
+    // Return 'true' if any properties updated on the passed object.
+    // Called at taint-time!
+    public override bool MakeStatic(BSPhysObject child)
+    {
+        // What is done for each object in BSPrim is what we want.
+        return false;
+    }
+
+    // Called at taint-time!!
+    public override void UpdateProperties(BSPhysObject updated)
+    {
+        // Nothing to do for constraints on property updates
+    }
+
+    // Routine used when rebuilding the body of the root of the linkset
+    // Destroy all the constraints have have been made to root.
+    // This is called when the root body is changing.
+    // Returns 'true' of something eas actually removed and would need restoring
+    // Called at taint-time!!
+    public override bool RemoveBodyDependencies(BSPrim child)
+    {
+        bool ret = false;
+
+        lock (m_linksetActivityLock)
+        {
+            if (IsRoot(child))
+            {
+                // If the one with the dependency is root, must undo all children
+                DetailLog("{0},BSLinkset.RemoveBodyDependencies,removeChildrenForRoot,rID={1},rBody={2}",
+                                                child.LocalID, LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"));
+
+                ret = PhysicallyUnlinkAllChildrenFromRoot(LinksetRoot);
+            }
+            else
+            {
+                DetailLog("{0},BSLinkset.RemoveBodyDependencies,removeSingleChild,rID={1},rBody={2},cID={3},cBody={4}",
+                                                child.LocalID,
+                                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"),
+                                                child.LocalID, child.BSBody.ptr.ToString("X"));
+                // ret = PhysicallyUnlinkAChildFromRoot(LinksetRoot, child);
+                // Despite the function name, this removes any link to the specified object.
+                ret = PhysicallyUnlinkAllChildrenFromRoot(child);
+            }
+        }
+        return ret;
+    }
+
+    // Companion to RemoveBodyDependencies(). If RemoveBodyDependencies() returns 'true',
+    // this routine will restore the removed constraints.
+    // Called at taint-time!!
+    public override void RestoreBodyDependencies(BSPrim child)
+    {
+        lock (m_linksetActivityLock)
+        {
+            if (IsRoot(child))
+            {
+                DetailLog("{0},BSLinkset.RestoreBodyDependencies,restoreChildrenForRoot,rID={1},numChild={2}",
+                                                child.LocalID, LinksetRoot.LocalID, m_taintChildren.Count);
+                foreach (BSPhysObject bpo in m_taintChildren)
+                {
+                    PhysicallyLinkAChildToRoot(LinksetRoot, bpo);
+                }
+            }
+            else
+            {
+                DetailLog("{0},BSLinkset.RestoreBodyDependencies,restoreSingleChild,rID={1},rBody={2},cID={3},cBody={4}",
+                                                LinksetRoot.LocalID,
+                                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"),
+                                                child.LocalID, child.BSBody.ptr.ToString("X"));
+                PhysicallyLinkAChildToRoot(LinksetRoot, child);
+            }
+        }
+    }
+
+    // ================================================================
+    // Below this point is internal magic
+
+    // I am the root of a linkset and a new child is being added
+    // Called while LinkActivity is locked.
+    protected override void AddChildToLinkset(BSPhysObject child)
+    {
+        if (!HasChild(child))
+        {
+            m_children.Add(child);
+
+            BSPhysObject rootx = LinksetRoot; // capture the root as of now
+            BSPhysObject childx = child;
+
+            DetailLog("{0},AddChildToLinkset,call,child={1}", LinksetRoot.LocalID, child.LocalID);
+
+            PhysicsScene.TaintedObject("AddChildToLinkset", delegate()
+            {
+                DetailLog("{0},AddChildToLinkset,taint,rID={1},rBody={2},cID={3},cBody={4}",
+                                rootx.LocalID,
+                                rootx.LocalID, rootx.BSBody.ptr.ToString("X"),
+                                childx.LocalID, childx.BSBody.ptr.ToString("X"));
+                // Since this is taint-time, the body and shape could have changed for the child
+                rootx.ForcePosition = rootx.Position;   // DEBUG
+                childx.ForcePosition = childx.Position;   // DEBUG
+                PhysicallyLinkAChildToRoot(rootx, childx);
+                m_taintChildren.Add(child);
+            });
+        }
+        return;
+    }
+
+    // Forcefully removing a child from a linkset.
+    // This is not being called by the child so we have to make sure the child doesn't think
+    //    it's still connected to the linkset.
+    // Normal OpenSimulator operation will never do this because other SceneObjectPart information
+    //    also has to be updated (like pointer to prim's parent).
+    protected override void RemoveChildFromOtherLinkset(BSPhysObject pchild)
+    {
+        pchild.Linkset = BSLinkset.Factory(PhysicsScene, pchild);
+        RemoveChildFromLinkset(pchild);
+    }
+
+    // I am the root of a linkset and one of my children is being removed.
+    // Safe to call even if the child is not really in my linkset.
+    protected override void RemoveChildFromLinkset(BSPhysObject child)
+    {
+        if (m_children.Remove(child))
+        {
+            BSPhysObject rootx = LinksetRoot; // capture the root and body as of now
+            BSPhysObject childx = child;
+
+            DetailLog("{0},RemoveChildFromLinkset,call,rID={1},rBody={2},cID={3},cBody={4}",
+                            childx.LocalID,
+                            rootx.LocalID, rootx.BSBody.ptr.ToString("X"),
+                            childx.LocalID, childx.BSBody.ptr.ToString("X"));
+
+            PhysicsScene.TaintedObject("RemoveChildFromLinkset", delegate()
+            {
+                m_taintChildren.Remove(child);
+                PhysicallyUnlinkAChildFromRoot(rootx, childx);
+                RecomputeLinksetConstraintVariables();
+            });
+
+        }
+        else
+        {
+            // This will happen if we remove the root of the linkset first. Non-fatal occurance.
+            // PhysicsScene.Logger.ErrorFormat("{0}: Asked to remove child from linkset that was not in linkset", LogHeader);
+        }
+        return;
+    }
+
+    // Create a constraint between me (root of linkset) and the passed prim (the child).
+    // Called at taint time!
+    private void PhysicallyLinkAChildToRoot(BSPhysObject rootPrim, BSPhysObject childPrim)
+    {
+        // Zero motion for children so they don't interpolate
+        childPrim.ZeroMotion();
+
+        // Relative position normalized to the root prim
+        // Essentually a vector pointing from center of rootPrim to center of childPrim
+        OMV.Vector3 childRelativePosition = childPrim.Position - rootPrim.Position;
+
+        // real world coordinate of midpoint between the two objects
+        OMV.Vector3 midPoint = rootPrim.Position + (childRelativePosition / 2);
+
+        DetailLog("{0},BSLinkset.PhysicallyLinkAChildToRoot,taint,root={1},rBody={2},child={3},cBody={4},rLoc={5},cLoc={6},midLoc={7}",
+                                        rootPrim.LocalID,
+                                        rootPrim.LocalID, rootPrim.BSBody.ptr.ToString("X"),
+                                        childPrim.LocalID, childPrim.BSBody.ptr.ToString("X"),
+                                        rootPrim.Position, childPrim.Position, midPoint);
+
+        // create a constraint that allows no freedom of movement between the two objects
+        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
+
+        BS6DofConstraint constrain = new BS6DofConstraint(
+                            PhysicsScene.World, rootPrim.BSBody, childPrim.BSBody, midPoint, true, true );
+
+        /* NOTE: below is an attempt to build constraint with full frame computation, etc.
+         *     Using the midpoint is easier since it lets the Bullet code manipulate the transforms
+         *     of the objects.
+         * Code left as a warning to future programmers.
+        // ==================================================================================
+        // relative position normalized to the root prim
+        OMV.Quaternion invThisOrientation = OMV.Quaternion.Inverse(rootPrim.Orientation);
+        OMV.Vector3 childRelativePosition = (childPrim.Position - rootPrim.Position) * invThisOrientation;
+
+        // relative rotation of the child to the parent
+        OMV.Quaternion childRelativeRotation = invThisOrientation * childPrim.Orientation;
+        OMV.Quaternion inverseChildRelativeRotation = OMV.Quaternion.Inverse(childRelativeRotation);
+
+        // create a constraint that allows no freedom of movement between the two objects
+        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
+        DetailLog("{0},BSLinkset.PhysicallyLinkAChildToRoot,taint,root={1},child={2}", rootPrim.LocalID, rootPrim.LocalID, childPrim.LocalID);
+        BS6DofConstraint constrain = new BS6DofConstraint(
+                        PhysicsScene.World, rootPrim.Body, childPrim.Body,
+                        OMV.Vector3.Zero,
+                        OMV.Quaternion.Inverse(rootPrim.Orientation),
+                        OMV.Vector3.Zero,
+                        OMV.Quaternion.Inverse(childPrim.Orientation),
+                        // A point half way between the parent and child
+                        // childRelativePosition/2,
+                        // childRelativeRotation,
+                        // childRelativePosition/2,
+                        // inverseChildRelativeRotation,
+                        true,
+                        true
+                        );
+        // ==================================================================================
+        */
+
+        PhysicsScene.Constraints.AddConstraint(constrain);
+
+        // zero linear and angular limits makes the objects unable to move in relation to each other
+        constrain.SetLinearLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
+        constrain.SetAngularLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
+
+        // tweek the constraint to increase stability
+        constrain.UseFrameOffset(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintUseFrameOffset));
+        constrain.TranslationalLimitMotor(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintEnableTransMotor),
+                        PhysicsScene.Params.linkConstraintTransMotorMaxVel,
+                        PhysicsScene.Params.linkConstraintTransMotorMaxForce);
+        constrain.SetCFMAndERP(PhysicsScene.Params.linkConstraintCFM, PhysicsScene.Params.linkConstraintERP);
+        if (PhysicsScene.Params.linkConstraintSolverIterations != 0f)
+        {
+            constrain.SetSolverIterations(PhysicsScene.Params.linkConstraintSolverIterations);
+        }
+    }
+
+    // Remove linkage between myself and a particular child
+    // The root and child bodies are passed in because we need to remove the constraint between
+    //      the bodies that were at unlink time.
+    // Called at taint time!
+    private bool PhysicallyUnlinkAChildFromRoot(BSPhysObject rootPrim, BSPhysObject childPrim)
+    {
+        bool ret = false;
+        DetailLog("{0},BSLinkset.PhysicallyUnlinkAChildFromRoot,taint,root={1},rBody={2},child={3},cBody={4}",
+                            rootPrim.LocalID,
+                            rootPrim.LocalID, rootPrim.BSBody.ptr.ToString("X"),
+                            childPrim.LocalID, childPrim.BSBody.ptr.ToString("X"));
+
+        // Find the constraint for this link and get rid of it from the overall collection and from my list
+        if (PhysicsScene.Constraints.RemoveAndDestroyConstraint(rootPrim.BSBody, childPrim.BSBody))
+        {
+            // Make the child refresh its location
+            BulletSimAPI.PushUpdate2(childPrim.BSBody.ptr);
+            ret = true;
+        }
+
+        return ret;
+    }
+
+    // Remove linkage between myself and any possible children I might have.
+    // Called at taint time!
+    private bool PhysicallyUnlinkAllChildrenFromRoot(BSPhysObject rootPrim)
+    {
+        DetailLog("{0},BSLinkset.PhysicallyUnlinkAllChildren,taint", rootPrim.LocalID);
+        bool ret = false;
+
+        if (PhysicsScene.Constraints.RemoveAndDestroyConstraint(rootPrim.BSBody))
+        {
+            ret = true;
+        }
+        return ret;
+    }
+
+    // Call each of the constraints that make up this linkset and recompute the
+    //    various transforms and variables. Used when objects are added or removed
+    //    from a linkset to make sure the constraints know about the new mass and
+    //    geometry.
+    // Must only be called at taint time!!
+    private void RecomputeLinksetConstraintVariables()
+    {
+        float linksetMass = LinksetMass;
+        foreach (BSPhysObject child in m_taintChildren)
+        {
+            BSConstraint constrain;
+            if (PhysicsScene.Constraints.TryGetConstraint(LinksetRoot.BSBody, child.BSBody, out constrain))
+            {
+                // DetailLog("{0},BSLinkset.RecomputeLinksetConstraintVariables,taint,child={1},mass={2},A={3},B={4}",
+                //         LinksetRoot.LocalID, child.LocalID, linksetMass, constrain.Body1.ID, constrain.Body2.ID);
+                constrain.RecomputeConstraintVariables(linksetMass);
+            }
+            else
+            {
+                // Non-fatal error that happens when children are being added to the linkset but
+                //    their constraints have not been created yet.
+                break;
+            }
+        }
+
+        // If the whole linkset is not here, doesn't make sense to recompute linkset wide values
+        if (m_children.Count == m_taintChildren.Count)
+        {
+            // If this is a multiple object linkset, set everybody's center of mass to the set's center of mass
+            OMV.Vector3 centerOfMass = ComputeLinksetCenterOfMass();
+            BulletSimAPI.SetCenterOfMassByPosRot2(LinksetRoot.BSBody.ptr,
+                                centerOfMass, OMV.Quaternion.Identity);
+            DetailLog("{0},BSLinkset.RecomputeLinksetConstraintVariables,setCenterOfMass,COM={1},rBody={2}",
+                                LinksetRoot.LocalID, centerOfMass, LinksetRoot.BSBody.ptr.ToString("X"));
+            foreach (BSPhysObject child in m_taintChildren)
+            {
+                BulletSimAPI.SetCenterOfMassByPosRot2(child.BSBody.ptr,
+                                centerOfMass, OMV.Quaternion.Identity);
+            }
+
+            // BulletSimAPI.DumpAllInfo2(PhysicsScene.World.ptr);  // DEBUG DEBUG DEBUG
+        }
+        return;
+    }
+}
+}
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
index ead6a08..538f905 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
@@ -46,7 +46,7 @@ public abstract class BSPhysObject : PhysicsActor
         PhysObjectName = name;
         TypeName = typeName;
 
-        Linkset = new BSLinkset(PhysicsScene, this);
+        Linkset = BSLinkset.Factory(PhysicsScene, this);
         LastAssetBuildFailed = false;
 
         CollisionCollection = new CollisionEventUpdate();
@@ -78,7 +78,7 @@ public abstract class BSPhysObject : PhysicsActor
     public PrimitiveBaseShape BaseShape { get; protected set; }
 
     // When the physical properties are updated, an EntityProperty holds the update values.
-    // Keep the current and last EntityProperties to enable computation of differences 
+    // Keep the current and last EntityProperties to enable computation of differences
     //      between the current update and the previous values.
     public EntityProperties CurrentEntityProperties { get; set; }
     public EntityProperties LastEntityProperties { get; set; }
@@ -213,7 +213,7 @@ public abstract class BSPhysObject : PhysicsActor
             UnSubscribeEvents();
         }
     }
-    public override void UnSubscribeEvents() { 
+    public override void UnSubscribeEvents() {
         // DetailLog("{0},{1}.UnSubscribeEvents,unsubscribing", LocalID, TypeName);
         SubscribedEventsMs = 0;
         PhysicsScene.TaintedObject(TypeName+".UnSubscribeEvents", delegate()
@@ -222,7 +222,7 @@ public abstract class BSPhysObject : PhysicsActor
         });
     }
     // Return 'true' if the simulator wants collision events
-    public override bool SubscribedEvents() { 
+    public override bool SubscribedEvents() {
         return (SubscribedEventsMs > 0);
     }
 
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
index aeeb4dd..38ab3de 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -173,6 +173,7 @@ public sealed class BSPrim : BSPhysObject
     }
     public override bool ForceBodyShapeRebuild(bool inTaintTime)
     {
+        LastAssetBuildFailed = false;
         BSScene.TaintCallback rebuildOperation = delegate()
         {
             _mass = CalculateMass();   // changing the shape changes the mass
@@ -295,7 +296,7 @@ public sealed class BSPrim : BSPhysObject
     private bool PositionSanityCheck()
     {
         bool ret = false;
-      
+
         // If totally below the ground, move the prim up
         // TODO: figure out the right solution for this... only for dynamic objects?
         /*
@@ -398,7 +399,7 @@ public sealed class BSPrim : BSPhysObject
             {
                 // Done at taint time so we're sure the physics engine is not using the variables
                 // Vehicle code changes the parameters for this vehicle type.
-                this._vehicle.ProcessTypeChange(type);
+                _vehicle.ProcessTypeChange(type);
             });
         }
     }
@@ -510,7 +511,7 @@ public sealed class BSPrim : BSPhysObject
             });
         }
     }
-    // Go directly to Bullet to get/set the value. 
+    // Go directly to Bullet to get/set the value.
     public override OMV.Quaternion ForceOrientation
     {
         get
@@ -768,7 +769,7 @@ public sealed class BSPrim : BSPhysObject
         }
     }
     public override bool FloatOnWater {
-        set { 
+        set {
             _floatOnWater = value;
             PhysicsScene.TaintedObject("BSPrim.setFloatOnWater", delegate()
             {
@@ -971,7 +972,7 @@ public sealed class BSPrim : BSPhysObject
                     if (hollowAmount > 0.0)
                         {
                         hollowVolume *= hollowAmount;
-   
+
                         switch (BaseShape.HollowShape)
                             {
                             case HollowShape.Square:
@@ -1245,13 +1246,14 @@ public sealed class BSPrim : BSPhysObject
         FillShapeInfo(out shapeData);
 
         // If this prim is part of a linkset, we must remove and restore the physical
-        //    links of the body is rebuilt.
+        //    links if the body is rebuilt.
         bool needToRestoreLinkset = false;
 
         // Create the correct physical representation for this type of object.
         // Updates BSBody and BSShape with the new information.
         // Ignore 'forceRebuild'. This routine makes the right choices and changes of necessary.
-        PhysicsScene.Shapes.GetBodyAndShape(false, PhysicsScene.World, this, shapeData, BaseShape, 
+        // Returns 'true' if either the body or the shape was changed.
+        PhysicsScene.Shapes.GetBodyAndShape(false, PhysicsScene.World, this, shapeData, BaseShape,
                         null, delegate(BulletBody dBody)
         {
             // Called if the current prim body is about to be destroyed.
@@ -1354,7 +1356,7 @@ public sealed class BSPrim : BSPhysObject
             DetailLog("{0},BSPrim.UpdateProperties,call,pos={1},orient={2},vel={3},accel={4},rotVel={5}",
                     LocalID, _position, _orientation, _velocity, _acceleration, _rotationalVelocity);
 
-            // BulletSimAPI.DumpRigidBody2(Scene.World.Ptr, BSBody.Ptr);
+            // BulletSimAPI.DumpRigidBody2(PhysicsScene.World.ptr, BSBody.ptr);   // DEBUG DEBUG DEBUG
 
             base.RequestPhysicsterseUpdate();
         }
@@ -1367,8 +1369,8 @@ public sealed class BSPrim : BSPhysObject
                     entprop.Acceleration, entprop.RotationalVelocity);
         }
              */
-        // The linkset implimentation might want to know about this.
 
+        // The linkset implimentation might want to know about this.
         Linkset.UpdateProperties(this);
     }
 }
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
index 6621d39..db0c99e 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
@@ -320,7 +320,7 @@ public class BSScene : PhysicsScene, IPhysicsParameters
     {
         m_log.Debug("[BULLETS UNMANAGED]:" + msg);
     }
-  
+
     // Called directly from unmanaged code so don't do much
     private void BulletLoggerPhysLog(string msg)
     {
@@ -545,7 +545,7 @@ public class BSScene : PhysicsScene, IPhysicsParameters
         }
 
         // This is a kludge to get avatar movement updates.
-        // The simulator expects collisions for avatars even if there are have been no collisions. 
+        // The simulator expects collisions for avatars even if there are have been no collisions.
         //    The event updates avatar animations and stuff.
         // If you fix avatar animation updates, remove this overhead and let normal collision processing happen.
         foreach (BSPhysObject bsp in m_avatars)
@@ -692,7 +692,6 @@ public class BSScene : PhysicsScene, IPhysicsParameters
     {
         if (_taintedObjects.Count > 0)  // save allocating new list if there is nothing to process
         {
-            // swizzle a new list into the list location so we can process what's there
             int taintCount = m_taintsToProcessPerStep;
             TaintCallbackEntry oneCallback = new TaintCallbackEntry();
             while (_taintedObjects.Count > 0 && taintCount-- > 0)
@@ -711,11 +710,12 @@ public class BSScene : PhysicsScene, IPhysicsParameters
                 {
                     try
                     {
-                        DetailLog("{0},BSScene.ProcessTaints,doTaint,id={1}", DetailLogZero, oneCallback.ident); // DEBUG DEBUG DEBUG
+                        DetailLog("{0},BSScene.ProcessTaints,doTaint,id={1}", DetailLogZero, oneCallback.ident);
                         oneCallback.callback();
                     }
                     catch (Exception e)
                     {
+                        DetailLog("{0},BSScene.ProcessTaints,doTaintException,id={1}", DetailLogZero, oneCallback.ident); // DEBUG DEBUG DEBUG
                         m_log.ErrorFormat("{0}: ProcessTaints: {1}: Exception: {2}", LogHeader, oneCallback.ident, e);
                     }
                 }
@@ -1333,7 +1333,7 @@ public class BSScene : PhysicsScene, IPhysicsParameters
         // Add the Flush() if debugging crashes to get all the messages written out.
         // PhysicsLogging.Flush();
     }
-    // used to fill in the LocalID when there isn't one
+    // Used to fill in the LocalID when there isn't one. It's the correct number of characters.
     public const string DetailLogZero = "0000000000";
 
 }
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
index d3ba273..30fa50a 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
@@ -36,7 +36,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 {
 public class BSShapeCollection : IDisposable
 {
-    // private static string LogHeader = "[BULLETSIM SHAPE COLLECTION]";
+    private static string LogHeader = "[BULLETSIM SHAPE COLLECTION]";
 
     protected BSScene PhysicsScene { get; set; }
 
@@ -89,7 +89,7 @@ public class BSShapeCollection : IDisposable
     //    higher level dependencies on the shape or body. Mostly used for LinkSets to
     //    remove the physical constraints before the body is destroyed.
     // Called at taint-time!!
-    public bool GetBodyAndShape(bool forceRebuild, BulletSim sim, BSPhysObject prim, 
+    public bool GetBodyAndShape(bool forceRebuild, BulletSim sim, BSPhysObject prim,
                     ShapeData shapeData, PrimitiveBaseShape pbs,
                     ShapeDestructionCallback shapeCallback, BodyDestructionCallback bodyCallback)
     {
@@ -105,7 +105,7 @@ public class BSShapeCollection : IDisposable
             // If we had to select a new shape geometry for the object,
             //    rebuild the body around it.
             // Updates prim.BSBody with information/pointers to requested body
-            bool newBody = CreateBody((newGeom || forceRebuild), prim, PhysicsScene.World, 
+            bool newBody = CreateBody((newGeom || forceRebuild), prim, PhysicsScene.World,
                                     prim.BSShape, shapeData, bodyCallback);
             ret = newGeom || newBody;
         }
@@ -325,7 +325,7 @@ public class BSShapeCollection : IDisposable
     // Info in prim.BSShape is updated to the new shape.
     // Returns 'true' if the geometry was rebuilt.
     // Called at taint-time!
-    private bool CreateGeom(bool forceRebuild, BSPhysObject prim, ShapeData shapeData, 
+    private bool CreateGeom(bool forceRebuild, BSPhysObject prim, ShapeData shapeData,
                             PrimitiveBaseShape pbs, ShapeDestructionCallback shapeCallback)
     {
         bool ret = false;
@@ -335,9 +335,10 @@ public class BSShapeCollection : IDisposable
         if (shapeData.Type == ShapeData.PhysicsShapeType.SHAPE_AVATAR)
         {
             // an avatar capsule is close to a native shape (it is not shared)
-            ret = GetReferenceToNativeShape(prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_AVATAR, 
+            ret = GetReferenceToNativeShape(prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_AVATAR,
                             ShapeData.FixedShapeKey.KEY_CAPSULE, shapeCallback);
             DetailLog("{0},BSShapeCollection.CreateGeom,avatarCapsule,shape={1}", prim.LocalID, prim.BSShape);
+            ret = true;
             haveShape = true;
         }
         // If the prim attributes are simple, this could be a simple Bullet native shape
@@ -362,7 +363,7 @@ public class BSShapeCollection : IDisposable
                         || prim.BSShape.type != ShapeData.PhysicsShapeType.SHAPE_SPHERE
                         )
                 {
-                    ret = GetReferenceToNativeShape(prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_SPHERE, 
+                    ret = GetReferenceToNativeShape(prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_SPHERE,
                                             ShapeData.FixedShapeKey.KEY_SPHERE, shapeCallback);
                     DetailLog("{0},BSShapeCollection.CreateGeom,sphere,force={1},shape={2}",
                                         prim.LocalID, forceRebuild, prim.BSShape);
@@ -376,7 +377,7 @@ public class BSShapeCollection : IDisposable
                         || prim.BSShape.type != ShapeData.PhysicsShapeType.SHAPE_BOX
                         )
                 {
-                    ret = GetReferenceToNativeShape( prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_BOX, 
+                    ret = GetReferenceToNativeShape( prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_BOX,
                                             ShapeData.FixedShapeKey.KEY_BOX, shapeCallback);
                     DetailLog("{0},BSShapeCollection.CreateGeom,box,force={1},shape={2}",
                                         prim.LocalID, forceRebuild, prim.BSShape);
@@ -411,39 +412,49 @@ public class BSShapeCollection : IDisposable
                             ShapeData.PhysicsShapeType shapeType, ShapeData.FixedShapeKey shapeKey,
                             ShapeDestructionCallback shapeCallback)
     {
+        // release any previous shape
+        DereferenceShape(prim.BSShape, true, shapeCallback);
 
         shapeData.Type = shapeType;
         // Bullet native objects are scaled by the Bullet engine so pass the size in
         prim.Scale = shapeData.Size;
         shapeData.Scale = shapeData.Size;
 
-        // release any previous shape
-        DereferenceShape(prim.BSShape, true, shapeCallback);
-
         BulletShape newShape = BuildPhysicalNativeShape(shapeType, shapeData, shapeKey);
 
         // Don't need to do a 'ReferenceShape()' here because native shapes are not shared.
-        DetailLog("{0},BSShapeCollection.AddNativeShapeToPrim,create,newshape={1},scale={2}", 
+        DetailLog("{0},BSShapeCollection.AddNativeShapeToPrim,create,newshape={1},scale={2}",
                                 shapeData.ID, newShape, shapeData.Scale);
 
         prim.BSShape = newShape;
         return true;
     }
 
-    private BulletShape BuildPhysicalNativeShape(ShapeData.PhysicsShapeType shapeType, 
+    private BulletShape BuildPhysicalNativeShape(ShapeData.PhysicsShapeType shapeType,
                         ShapeData shapeData, ShapeData.FixedShapeKey shapeKey)
     {
         BulletShape newShape;
+        // Need to make sure the passed shape information is for the native type.
+        ShapeData nativeShapeData = shapeData;
+        nativeShapeData.Type = shapeType;
+        nativeShapeData.MeshKey = (ulong)shapeKey;
+        nativeShapeData.HullKey = (ulong)shapeKey;
 
         if (shapeType == ShapeData.PhysicsShapeType.SHAPE_AVATAR)
         {
             newShape = new BulletShape(
-                        BulletSimAPI.BuildCapsuleShape2(PhysicsScene.World.ptr, 1.0f, 1.0f, shapeData.Scale), 
-                        shapeType);
+                        BulletSimAPI.BuildCapsuleShape2(PhysicsScene.World.ptr, 1f, 1f, nativeShapeData.Scale)
+                        , shapeType);
+            DetailLog("{0},BSShapeCollection.BuiletPhysicalNativeShape,capsule,scale={1}", nativeShapeData.ID, nativeShapeData.Scale);
         }
         else
         {
-            newShape = new BulletShape(BulletSimAPI.BuildNativeShape2(PhysicsScene.World.ptr, shapeData), shapeType);
+            newShape = new BulletShape(BulletSimAPI.BuildNativeShape2(PhysicsScene.World.ptr, nativeShapeData), shapeType);
+        }
+        if (newShape.ptr == IntPtr.Zero)
+        {
+            PhysicsScene.Logger.ErrorFormat("{0} BuildPhysicalNativeShape failed. ID={1}, shape={2}",
+                                    LogHeader, nativeShapeData.ID, nativeShapeData.Type);
         }
         newShape.shapeKey = (System.UInt64)shapeKey;
         newShape.isNativeShape = true;
@@ -698,19 +709,26 @@ public class BSShapeCollection : IDisposable
         return ComputeShapeKey(shapeData, pbs, out lod);
     }
 
+    // The creation of a mesh or hull can fail if an underlying asset is not available.
+    // There are two cases: 1) the asset is not in the cache and it needs to be fetched;
+    //     and 2) the asset cannot be converted (like decompressing JPEG2000s).
+    //     The first case causes the asset to be fetched. The second case just requires
+    //     us to not loop forever.
+    // Called after creating a physical mesh or hull. If the physical shape was created,
+    //     just return.
     private BulletShape VerifyMeshCreated(BulletShape newShape, BSPhysObject prim, ShapeData shapeData, PrimitiveBaseShape pbs)
     {
         // If the shape was successfully created, nothing more to do
         if (newShape.ptr != IntPtr.Zero)
             return newShape;
 
-        // The most common reason for failure is that an underlying asset is not available
-
         // If this mesh has an underlying asset and we have not failed getting it before, fetch the asset
         if (pbs.SculptEntry && !prim.LastAssetBuildFailed && pbs.SculptTexture != OMV.UUID.Zero)
         {
             prim.LastAssetBuildFailed = true;
             BSPhysObject xprim = prim;
+            DetailLog("{0},BSShapeCollection.VerifyMeshCreated,fetchAsset,lID={1},lastFailed={2}",
+                            LogHeader, shapeData.ID.ToString("X"), prim.LastAssetBuildFailed);
             Util.FireAndForget(delegate
                 {
                     RequestAssetDelegate assetProvider = PhysicsScene.RequestAssetMethod;
@@ -724,20 +742,28 @@ public class BSShapeCollection : IDisposable
                             if (yprim.BaseShape.SculptTexture.ToString() != asset.ID)
                                 return;
 
-                            yprim.BaseShape.SculptData = new byte[asset.Data.Length];
-                            asset.Data.CopyTo(yprim.BaseShape.SculptData, 0);
+                            yprim.BaseShape.SculptData = asset.Data;
                             // This will cause the prim to see that the filler shape is not the right
                             //    one and try again to build the object.
+                            // No race condition with the native sphere setting since the rebuild is at taint time.
                             yprim.ForceBodyShapeRebuild(false);
 
                         });
                     }
                 });
         }
+        else
+        {
+            if (prim.LastAssetBuildFailed)
+            {
+                PhysicsScene.Logger.ErrorFormat("{0} Mesh failed to fetch asset. lID={1}, texture={2}",
+                                            LogHeader, shapeData.ID, pbs.SculptTexture);
+            }
+        }
 
         // While we figure out the real problem, stick a simple native shape on the object.
         BulletShape fillinShape =
-            BuildPhysicalNativeShape(ShapeData.PhysicsShapeType.SHAPE_SPHERE, shapeData, ShapeData.FixedShapeKey.KEY_SPHERE);
+            BuildPhysicalNativeShape(ShapeData.PhysicsShapeType.SHAPE_BOX, shapeData, ShapeData.FixedShapeKey.KEY_BOX);
 
         return fillinShape;
     }
@@ -746,7 +772,7 @@ public class BSShapeCollection : IDisposable
     // Updates prim.BSBody with the information about the new body if one is created.
     // Returns 'true' if an object was actually created.
     // Called at taint-time.
-    private bool CreateBody(bool forceRebuild, BSPhysObject prim, BulletSim sim, BulletShape shape, 
+    private bool CreateBody(bool forceRebuild, BSPhysObject prim, BulletSim sim, BulletShape shape,
                             ShapeData shapeData, BodyDestructionCallback bodyCallback)
     {
         bool ret = false;
@@ -765,7 +791,6 @@ public class BSShapeCollection : IDisposable
                 // If the collisionObject is not the correct type for solidness, rebuild what's there
                 mustRebuild = true;
             }
-
         }
 
         if (mustRebuild || forceRebuild)
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs b/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
index 4106534..880859a 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
@@ -201,9 +201,7 @@ public class BSTerrainManager
     // If called with a mapInfo in m_heightMaps and there is an existing terrain body, a new
     //     terrain shape is created and added to the body.
     //     This call is most often used to update the heightMap and parameters of the terrain.
-    // The 'doNow' boolean says whether to do all the unmanaged activities right now (like when
-    //     calling this routine from initialization or taint-time routines) or whether to delay
-    //     all the unmanaged activities to taint-time.
+    // (The above does suggest that some simplification/refactoring is in order.)
     private void UpdateOrCreateTerrain(uint id, float[] heightMap, Vector3 minCoords, Vector3 maxCoords, bool inTaintTime)
     {
         DetailLog("{0},BSTerrainManager.UpdateOrCreateTerrain,call,minC={1},maxC={2},inTaintTime={3}",
@@ -335,8 +333,8 @@ public class BSTerrainManager
 
                 // Make sure the new shape is processed.
                 // BulletSimAPI.Activate2(mapInfo.terrainBody.ptr, true);
-                BulletSimAPI.ForceActivationState2(mapInfo.terrainBody.ptr, ActivationState.ISLAND_SLEEPING);
-                // BulletSimAPI.ForceActivationState2(mapInfo.terrainBody.ptr, ActivationState.DISABLE_SIMULATION);
+                // BulletSimAPI.ForceActivationState2(mapInfo.terrainBody.ptr, ActivationState.ISLAND_SLEEPING);
+                BulletSimAPI.ForceActivationState2(mapInfo.terrainBody.ptr, ActivationState.DISABLE_SIMULATION);
 
                 m_terrainModified = true;
             };