diff --git a/cmake/templates/NSIS.template.in b/cmake/templates/NSIS.template.in
index 710fd81316..f44c8185d8 100644
--- a/cmake/templates/NSIS.template.in
+++ b/cmake/templates/NSIS.template.in
@@ -49,7 +49,7 @@
     Var STR_CONTAINS_VAR_3
     Var STR_CONTAINS_VAR_4
     Var STR_RETURN_VAR
-
+    
     Function StrContains
       Exch $STR_NEEDLE
       Exch 1
@@ -438,6 +438,7 @@ Var DesktopServerCheckbox
 Var ServerStartupCheckbox
 Var LaunchServerNowCheckbox
 Var LaunchClientNowCheckbox
+Var CleanInstallCheckbox
 Var CurrentOffset
 Var OffsetUnits
 Var CopyFromProductionCheckbox
@@ -475,27 +476,18 @@ Function PostInstallOptionsPage
     ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Create a desktop shortcut for @INTERFACE_HF_SHORTCUT_NAME@"
     Pop $DesktopClientCheckbox
     IntOp $CurrentOffset $CurrentOffset + 15
-
+    
     ; set the checkbox state depending on what is present in the registry
     !insertmacro SetPostInstallOption $DesktopClientCheckbox @CLIENT_DESKTOP_SHORTCUT_REG_KEY@ ${BST_CHECKED}
   ${EndIf}
-
+  
   ${If} ${SectionIsSelected} ${@SERVER_COMPONENT_NAME@}
     ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Create a desktop shortcut for @CONSOLE_HF_SHORTCUT_NAME@"
     Pop $DesktopServerCheckbox
-
+    IntOp $CurrentOffset $CurrentOffset + 15
+    
     ; set the checkbox state depending on what is present in the registry
     !insertmacro SetPostInstallOption $DesktopServerCheckbox @CONSOLE_DESKTOP_SHORTCUT_REG_KEY@ ${BST_UNCHECKED}
-
-    IntOp $CurrentOffset $CurrentOffset + 15
-
-    ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Launch @CONSOLE_HF_SHORTCUT_NAME@ on startup"
-    Pop $ServerStartupCheckbox
-
-    ; set the checkbox state depending on what is present in the registry
-    !insertmacro SetPostInstallOption $ServerStartupCheckbox @CONSOLE_STARTUP_REG_KEY@ ${BST_CHECKED}
-
-    IntOp $CurrentOffset $CurrentOffset + 15
   ${EndIf}
 
   ${If} ${SectionIsSelected} ${@SERVER_COMPONENT_NAME@}
@@ -511,17 +503,33 @@ Function PostInstallOptionsPage
 
     IntOp $CurrentOffset $CurrentOffset + 15
   ${EndIf}
-
+  
   ${If} ${SectionIsSelected} ${@CLIENT_COMPONENT_NAME@}
-	  ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Launch @INTERFACE_HF_SHORTCUT_NAME@ after install"
-	  Pop $LaunchClientNowCheckbox
-
-	  ; set the checkbox state depending on what is present in the registry
-	  !insertmacro SetPostInstallOption $LaunchClientNowCheckbox @CLIENT_LAUNCH_NOW_REG_KEY@ ${BST_CHECKED}
-      ${StrContains} $substringResult "/forceNoLaunchClient" $CMDLINE
-      ${IfNot} $substringResult == ""
-          ${NSD_SetState} $LaunchClientNowCheckbox ${BST_UNCHECKED}
-      ${EndIf}
+    ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Launch @INTERFACE_HF_SHORTCUT_NAME@ after install"
+    Pop $LaunchClientNowCheckbox
+    IntOp $CurrentOffset $CurrentOffset + 30
+    
+    ; set the checkbox state depending on what is present in the registry
+    !insertmacro SetPostInstallOption $LaunchClientNowCheckbox @CLIENT_LAUNCH_NOW_REG_KEY@ ${BST_CHECKED}
+    ${StrContains} $substringResult "/forceNoLaunchClient" $CMDLINE
+    ${IfNot} $substringResult == ""
+    ${NSD_SetState} $LaunchClientNowCheckbox ${BST_UNCHECKED}
+    ${EndIf}
+  ${EndIf}
+  
+  ${If} ${SectionIsSelected} ${@SERVER_COMPONENT_NAME@}
+    ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Launch @CONSOLE_HF_SHORTCUT_NAME@ on startup"
+    Pop $ServerStartupCheckbox
+    IntOp $CurrentOffset $CurrentOffset + 15
+    
+    ; set the checkbox state depending on what is present in the registry
+    !insertmacro SetPostInstallOption $ServerStartupCheckbox @CONSOLE_STARTUP_REG_KEY@ ${BST_CHECKED}
+  ${EndIf}
+  
+  ${If} ${SectionIsSelected} ${@CLIENT_COMPONENT_NAME@}
+    ${NSD_CreateCheckbox} 0 $CurrentOffset$OffsetUnits 100% 10u "&Perform a clean install (Delete older settings and content)"
+    Pop $CleanInstallCheckbox
+    IntOp $CurrentOffset $CurrentOffset + 15
   ${EndIf}
 
   ${If} @PR_BUILD@ == 1
@@ -543,7 +551,7 @@ Function PostInstallOptionsPage
 
     ${NSD_SetState} $CopyFromProductionCheckbox ${BST_CHECKED}
   ${EndIf}
-
+  
   nsDialogs::Show
 FunctionEnd
 
@@ -558,6 +566,7 @@ Var ServerStartupState
 Var LaunchServerNowState
 Var LaunchClientNowState
 Var CopyFromProductionState
+Var CleanInstallState
 
 Function ReadPostInstallOptions
   ${If} ${SectionIsSelected} ${@CLIENT_COMPONENT_NAME@}
@@ -579,13 +588,18 @@ Function ReadPostInstallOptions
   ${EndIf}
 
   ${If} ${SectionIsSelected} ${@SERVER_COMPONENT_NAME@}
-	  ; check if we need to launch the server post-install
-	  ${NSD_GetState} $LaunchServerNowCheckbox $LaunchServerNowState
+    ; check if we need to launch the server post-install
+    ${NSD_GetState} $LaunchServerNowCheckbox $LaunchServerNowState
   ${EndIf}
-
+  
   ${If} ${SectionIsSelected} ${@CLIENT_COMPONENT_NAME@}
-	  ; check if we need to launch the client post-install
-	  ${NSD_GetState} $LaunchClientNowCheckbox $LaunchClientNowState
+    ; check if we need to launch the client post-install
+    ${NSD_GetState} $LaunchClientNowCheckbox $LaunchClientNowState
+  ${EndIf}
+   
+  ${If} ${SectionIsSelected} ${@CLIENT_COMPONENT_NAME@}
+    ; check if the user asked for a clean install
+    ${NSD_GetState} $CleanInstallCheckbox $CleanInstallState
   ${EndIf}
 FunctionEnd
 
@@ -628,6 +642,15 @@ Function HandlePostInstallOptions
       !insertmacro WritePostInstallOption @CONSOLE_STARTUP_REG_KEY@ NO
     ${EndIf}
   ${EndIf}
+  
+  ${If} ${SectionIsSelected} ${@CLIENT_COMPONENT_NAME@}
+    ; check if the user asked for a clean install
+    ${If} $CleanInstallState == ${BST_CHECKED}
+      SetShellVarContext current
+      RMDir /r "$APPDATA\@BUILD_ORGANIZATION@"
+      RMDir /r "$LOCALAPPDATA\@BUILD_ORGANIZATION@"
+    ${EndIf}
+  ${EndIf}
 
   ${If} @PR_BUILD@ == 1
 
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index d886b87644..707fc7b98b 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -69,6 +69,7 @@
 #include <EntityScriptClient.h>
 #include <EntityScriptServerLogClient.h>
 #include <EntityScriptingInterface.h>
+#include <HoverOverlayInterface.h>
 #include <ErrorDialog.h>
 #include <FileScriptingInterface.h>
 #include <Finally.h>
@@ -588,6 +589,7 @@ bool setupEssentials(int& argc, char** argv, bool runningMarkerExisted) {
     DependencyManager::set<Snapshot>();
     DependencyManager::set<CloseEventSender>();
     DependencyManager::set<ResourceManager>();
+    DependencyManager::set<HoverOverlayInterface>();
 
     return previousSessionCrashed;
 }
diff --git a/libraries/animation/src/AnimInverseKinematics.cpp b/libraries/animation/src/AnimInverseKinematics.cpp
index d7076a443e..57c00e7183 100644
--- a/libraries/animation/src/AnimInverseKinematics.cpp
+++ b/libraries/animation/src/AnimInverseKinematics.cpp
@@ -23,20 +23,23 @@
 #include "CubicHermiteSpline.h"
 #include "AnimUtil.h"
 
-static void lookupJointChainInfo(AnimInverseKinematics::JointChainInfo* jointChainInfos, size_t numJointChainInfos,
+static const float JOINT_CHAIN_INTERP_TIME = 0.25f;
+
+static void lookupJointInfo(const AnimInverseKinematics::JointChainInfo& jointChainInfo,
                                  int indexA, int indexB,
-                                 AnimInverseKinematics::JointChainInfo** jointChainInfoA,
-                                 AnimInverseKinematics::JointChainInfo** jointChainInfoB) {
-    *jointChainInfoA = nullptr;
-    *jointChainInfoB = nullptr;
-    for (size_t i = 0; i < numJointChainInfos; i++) {
-        if (jointChainInfos[i].jointIndex == indexA) {
-            *jointChainInfoA = jointChainInfos + i;
+                                 const AnimInverseKinematics::JointInfo** jointInfoA,
+                                 const AnimInverseKinematics::JointInfo** jointInfoB) {
+    *jointInfoA = nullptr;
+    *jointInfoB = nullptr;
+    for (size_t i = 0; i < jointChainInfo.jointInfoVec.size(); i++) {
+        const AnimInverseKinematics::JointInfo* jointInfo = &jointChainInfo.jointInfoVec[i];
+        if (jointInfo->jointIndex == indexA) {
+            *jointInfoA = jointInfo;
         }
-        if (jointChainInfos[i].jointIndex == indexB) {
-            *jointChainInfoB = jointChainInfos + i;
+        if (jointInfo->jointIndex == indexB) {
+            *jointInfoB = jointInfo;
         }
-        if (*jointChainInfoA && *jointChainInfoB) {
+        if (*jointInfoA && *jointInfoB) {
             break;
         }
     }
@@ -149,25 +152,28 @@ void AnimInverseKinematics::setTargetVars(const QString& jointName, const QStrin
 }
 
 void AnimInverseKinematics::computeTargets(const AnimVariantMap& animVars, std::vector<IKTarget>& targets, const AnimPoseVec& underPoses) {
-    // build a list of valid targets from _targetVarVec and animVars
-    _maxTargetIndex = -1;
+
     _hipsTargetIndex = -1;
-    bool removeUnfoundJoints = false;
+
+    targets.reserve(_targetVarVec.size());
 
     for (auto& targetVar : _targetVarVec) {
+
+        // update targetVar jointIndex cache
         if (targetVar.jointIndex == -1) {
-            // this targetVar hasn't been validated yet...
             int jointIndex = _skeleton->nameToJointIndex(targetVar.jointName);
             if (jointIndex >= 0) {
                 // this targetVar has a valid joint --> cache the indices
                 targetVar.jointIndex = jointIndex;
             } else {
                 qCWarning(animation) << "AnimInverseKinematics could not find jointName" << targetVar.jointName << "in skeleton";
-                removeUnfoundJoints = true;
             }
-        } else {
-            IKTarget target;
+        }
+
+        IKTarget target;
+        if (targetVar.jointIndex != -1) {
             target.setType(animVars.lookup(targetVar.typeVar, (int)IKTarget::Type::RotationAndPosition));
+            target.setIndex(targetVar.jointIndex);
             if (target.getType() != IKTarget::Type::Unknown) {
                 AnimPose absPose = _skeleton->getAbsolutePose(targetVar.jointIndex, underPoses);
                 glm::quat rotation = animVars.lookupRigToGeometry(targetVar.rotationVar, absPose.rot());
@@ -175,7 +181,6 @@ void AnimInverseKinematics::computeTargets(const AnimVariantMap& animVars, std::
                 float weight = animVars.lookup(targetVar.weightVar, targetVar.weight);
 
                 target.setPose(rotation, translation);
-                target.setIndex(targetVar.jointIndex);
                 target.setWeight(weight);
                 target.setFlexCoefficients(targetVar.numFlexCoefficients, targetVar.flexCoefficients);
 
@@ -188,39 +193,20 @@ void AnimInverseKinematics::computeTargets(const AnimVariantMap& animVars, std::
                 glm::vec3 poleReferenceVector = animVars.lookupRigToGeometryVector(targetVar.poleReferenceVectorVar, Vectors::UNIT_Z);
                 target.setPoleReferenceVector(glm::normalize(poleReferenceVector));
 
-                targets.push_back(target);
-
-                if (targetVar.jointIndex > _maxTargetIndex) {
-                    _maxTargetIndex = targetVar.jointIndex;
-                }
-
                 // record the index of the hips ik target.
                 if (target.getIndex() == _hipsIndex) {
-                    _hipsTargetIndex = (int)targets.size() - 1;
+                    _hipsTargetIndex = (int)targets.size();
                 }
             }
+        } else {
+            target.setType((int)IKTarget::Type::Unknown);
         }
-    }
 
-    if (removeUnfoundJoints) {
-        int numVars = (int)_targetVarVec.size();
-        int i = 0;
-        while (i < numVars) {
-            if (_targetVarVec[i].jointIndex == -1) {
-                if (numVars > 1) {
-                    // swap i for last element
-                    _targetVarVec[i] = _targetVarVec[numVars - 1];
-                }
-                _targetVarVec.pop_back();
-                --numVars;
-            } else {
-                ++i;
-            }
-        }
+        targets.push_back(target);
     }
 }
 
-void AnimInverseKinematics::solve(const AnimContext& context, const std::vector<IKTarget>& targets) {
+void AnimInverseKinematics::solve(const AnimContext& context, const std::vector<IKTarget>& targets, float dt, JointChainInfoVec& jointChainInfoVec) {
     // compute absolute poses that correspond to relative target poses
     AnimPoseVec absolutePoses;
     absolutePoses.resize(_relativePoses.size());
@@ -234,26 +220,75 @@ void AnimInverseKinematics::solve(const AnimContext& context, const std::vector<
         accumulator.clearAndClean();
     }
 
-    float maxError = FLT_MAX;
+    float maxError = 0.0f;
     int numLoops = 0;
     const int MAX_IK_LOOPS = 16;
-    const float MAX_ERROR_TOLERANCE = 0.1f; // cm
-    while (maxError > MAX_ERROR_TOLERANCE && numLoops < MAX_IK_LOOPS) {
+    while (numLoops < MAX_IK_LOOPS) {
         ++numLoops;
 
         bool debug = context.getEnableDebugDrawIKChains() && numLoops == MAX_IK_LOOPS;
 
         // solve all targets
-        for (auto& target: targets) {
-            if (target.getType() == IKTarget::Type::Spline) {
-                solveTargetWithSpline(context, target, absolutePoses, debug);
-            } else {
-                solveTargetWithCCD(context, target, absolutePoses, debug);
+        for (size_t i = 0; i < targets.size(); i++) {
+            switch (targets[i].getType()) {
+            case IKTarget::Type::Unknown:
+                break;
+            case IKTarget::Type::Spline:
+                solveTargetWithSpline(context, targets[i], absolutePoses, debug, jointChainInfoVec[i]);
+                break;
+            default:
+                solveTargetWithCCD(context, targets[i], absolutePoses, debug, jointChainInfoVec[i]);
+                break;
+            }
+        }
+
+        // on last iteration, interpolate jointChains, if necessary
+        if (numLoops == MAX_IK_LOOPS) {
+            for (size_t i = 0; i < _prevJointChainInfoVec.size(); i++) {
+                if (_prevJointChainInfoVec[i].timer > 0.0f) {
+                    float alpha = (JOINT_CHAIN_INTERP_TIME - _prevJointChainInfoVec[i].timer) / JOINT_CHAIN_INTERP_TIME;
+                    size_t chainSize = std::min(_prevJointChainInfoVec[i].jointInfoVec.size(), jointChainInfoVec[i].jointInfoVec.size());
+                    for (size_t j = 0; j < chainSize; j++) {
+                        jointChainInfoVec[i].jointInfoVec[j].rot = safeMix(_prevJointChainInfoVec[i].jointInfoVec[j].rot, jointChainInfoVec[i].jointInfoVec[j].rot, alpha);
+                        jointChainInfoVec[i].jointInfoVec[j].trans = lerp(_prevJointChainInfoVec[i].jointInfoVec[j].trans, jointChainInfoVec[i].jointInfoVec[j].trans, alpha);
+                    }
+
+                    // if joint chain was just disabled, ramp the weight toward zero.
+                    if (_prevJointChainInfoVec[i].target.getType() != IKTarget::Type::Unknown &&
+                        jointChainInfoVec[i].target.getType() == IKTarget::Type::Unknown) {
+                        IKTarget newTarget = _prevJointChainInfoVec[i].target;
+                        newTarget.setWeight((1.0f - alpha) * _prevJointChainInfoVec[i].target.getWeight());
+                        jointChainInfoVec[i].target = newTarget;
+                    }
+                }
+            }
+        }
+
+        // copy jointChainInfoVecs into accumulators
+        for (size_t i = 0; i < targets.size(); i++) {
+            const std::vector<JointInfo>& jointInfoVec = jointChainInfoVec[i].jointInfoVec;
+
+            // don't accumulate disabled or rotation only ik targets.
+            IKTarget::Type type = jointChainInfoVec[i].target.getType();
+            if (type != IKTarget::Type::Unknown && type != IKTarget::Type::RotationOnly) {
+                float weight = jointChainInfoVec[i].target.getWeight();
+                if (weight > 0.0f) {
+                    for (size_t j = 0; j < jointInfoVec.size(); j++) {
+                        const JointInfo& info = jointInfoVec[j];
+                        if (info.jointIndex >= 0) {
+                            _rotationAccumulators[info.jointIndex].add(info.rot, weight);
+                            _translationAccumulators[info.jointIndex].add(info.trans, weight);
+                        }
+                    }
+                }
             }
         }
 
         // harvest accumulated rotations and apply the average
         for (int i = 0; i < (int)_relativePoses.size(); ++i) {
+            if (i == _hipsIndex) {
+                continue;  // don't apply accumulators to hips
+            }
             if (_rotationAccumulators[i].size() > 0) {
                 _relativePoses[i].rot() = _rotationAccumulators[i].getAverage();
                 _rotationAccumulators[i].clear();
@@ -289,7 +324,7 @@ void AnimInverseKinematics::solve(const AnimContext& context, const std::vector<
     // finally set the relative rotation of each tip to agree with absolute target rotation
     for (auto& target: targets) {
         int tipIndex = target.getIndex();
-        int parentIndex = _skeleton->getParentIndex(tipIndex);
+        int parentIndex = (tipIndex >= 0) ? _skeleton->getParentIndex(tipIndex) : -1;
 
         // update rotationOnly targets that don't lie on the ik chain of other ik targets.
         if (parentIndex != -1 && !_rotationAccumulators[tipIndex].isDirty() && target.getType() == IKTarget::Type::RotationOnly) {
@@ -308,9 +343,34 @@ void AnimInverseKinematics::solve(const AnimContext& context, const std::vector<
             absolutePoses[tipIndex].rot() = targetRotation;
         }
     }
+
+    // copy jointChainInfoVec into _prevJointChainInfoVec, and update timers
+    for (size_t i = 0; i < jointChainInfoVec.size(); i++) {
+        _prevJointChainInfoVec[i].timer = _prevJointChainInfoVec[i].timer - dt;
+        if (_prevJointChainInfoVec[i].timer <= 0.0f) {
+            _prevJointChainInfoVec[i] = jointChainInfoVec[i];
+            _prevJointChainInfoVec[i].target = targets[i];
+            // store relative poses into unknown/rotation only joint chains.
+            // so we have something to interpolate from if this chain is activated.
+            IKTarget::Type type = _prevJointChainInfoVec[i].target.getType();
+            if (type == IKTarget::Type::Unknown || type == IKTarget::Type::RotationOnly) {
+                for (size_t j = 0; j < _prevJointChainInfoVec[i].jointInfoVec.size(); j++) {
+                    auto& info = _prevJointChainInfoVec[i].jointInfoVec[j];
+                    if (info.jointIndex >= 0) {
+                        info.rot = _relativePoses[info.jointIndex].rot();
+                        info.trans = _relativePoses[info.jointIndex].trans();
+                    } else {
+                        info.rot = Quaternions::IDENTITY;
+                        info.trans = glm::vec3(0.0f);
+                    }
+                }
+            }
+        }
+    }
 }
 
-void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses, bool debug) {
+void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses,
+                                               bool debug, JointChainInfo& jointChainInfoOut) const {
     size_t chainDepth = 0;
 
     IKTarget::Type targetType = target.getType();
@@ -338,9 +398,6 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
     // the tip's parent-relative as we proceed up the chain
     glm::quat tipParentOrientation = absolutePoses[pivotIndex].rot();
 
-    const size_t MAX_CHAIN_DEPTH = 30;
-    JointChainInfo jointChainInfos[MAX_CHAIN_DEPTH];
-
     // NOTE: if this code is removed, the head will remain rigid, causing the spine/hips to thrust forward backward
     // as the head is nodded.
     if (targetType == IKTarget::Type::HmdHead ||
@@ -368,7 +425,7 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
         }
 
         glm::vec3 tipRelativeTranslation = _relativePoses[target.getIndex()].trans();
-        jointChainInfos[chainDepth] = { tipRelativeRotation, tipRelativeTranslation, target.getWeight(), tipIndex, constrained };
+        jointChainInfoOut.jointInfoVec[chainDepth] = { tipRelativeRotation, tipRelativeTranslation, tipIndex, constrained };
     }
 
     // cache tip absolute position
@@ -379,7 +436,7 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
     // descend toward root, pivoting each joint to get tip closer to target position
     while (pivotIndex != _hipsIndex && pivotsParentIndex != -1) {
 
-        assert(chainDepth < MAX_CHAIN_DEPTH);
+        assert(chainDepth < jointChainInfoOut.jointInfoVec.size());
 
         // compute the two lines that should be aligned
         glm::vec3 jointPosition = absolutePoses[pivotIndex].trans();
@@ -444,9 +501,8 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
                             glm::quat twistPart;
                             glm::vec3 axis = glm::normalize(deltaRotation * leverArm);
                             swingTwistDecomposition(missingRotation, axis, swingPart, twistPart);
-                            float dotSign = copysignf(1.0f, twistPart.w);
                             const float LIMIT_LEAK_FRACTION = 0.1f;
-                            deltaRotation = glm::normalize(glm::lerp(glm::quat(), dotSign * twistPart, LIMIT_LEAK_FRACTION)) * deltaRotation;
+                            deltaRotation = safeLerp(glm::quat(), twistPart, LIMIT_LEAK_FRACTION);
                         }
                     }
                 }
@@ -455,9 +511,8 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
             // An HmdHead target slaves the orientation of the end-effector by distributing rotation
             // deltas up the hierarchy.  Its target position is enforced later (by shifting the hips).
             deltaRotation = target.getRotation() * glm::inverse(tipOrientation);
-            float dotSign = copysignf(1.0f, deltaRotation.w);
             const float ANGLE_DISTRIBUTION_FACTOR = 0.45f;
-            deltaRotation = glm::normalize(glm::lerp(glm::quat(), dotSign * deltaRotation, ANGLE_DISTRIBUTION_FACTOR));
+            deltaRotation = safeLerp(glm::quat(), deltaRotation, ANGLE_DISTRIBUTION_FACTOR);
         }
 
         // compute joint's new parent-relative rotation after swing
@@ -480,7 +535,7 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
         }
 
         glm::vec3 newTrans = _relativePoses[pivotIndex].trans();
-        jointChainInfos[chainDepth] = { newRot, newTrans, target.getWeight(), pivotIndex, constrained };
+        jointChainInfoOut.jointInfoVec[chainDepth] = { newRot, newTrans, pivotIndex, constrained };
 
         // keep track of tip's new transform as we descend towards root
         tipPosition = jointPosition + deltaRotation * (tipPosition - jointPosition);
@@ -502,24 +557,25 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
                 int baseParentJointIndex = _skeleton->getParentIndex(baseJointIndex);
                 AnimPose topPose, midPose, basePose;
                 int topChainIndex = -1, baseChainIndex = -1;
+                const size_t MAX_CHAIN_DEPTH = 30;
                 AnimPose postAbsPoses[MAX_CHAIN_DEPTH];
                 AnimPose accum = absolutePoses[_hipsIndex];
                 AnimPose baseParentPose = absolutePoses[_hipsIndex];
                 for (int i = (int)chainDepth - 1; i >= 0; i--) {
-                    accum = accum * AnimPose(glm::vec3(1.0f), jointChainInfos[i].relRot, jointChainInfos[i].relTrans);
+                    accum = accum * AnimPose(glm::vec3(1.0f), jointChainInfoOut.jointInfoVec[i].rot, jointChainInfoOut.jointInfoVec[i].trans);
                     postAbsPoses[i] = accum;
-                    if (jointChainInfos[i].jointIndex == topJointIndex) {
+                    if (jointChainInfoOut.jointInfoVec[i].jointIndex == topJointIndex) {
                         topChainIndex = i;
                         topPose = accum;
                     }
-                    if (jointChainInfos[i].jointIndex == midJointIndex) {
+                    if (jointChainInfoOut.jointInfoVec[i].jointIndex == midJointIndex) {
                         midPose = accum;
                     }
-                    if (jointChainInfos[i].jointIndex == baseJointIndex) {
+                    if (jointChainInfoOut.jointInfoVec[i].jointIndex == baseJointIndex) {
                         baseChainIndex = i;
                         basePose = accum;
                     }
-                    if (jointChainInfos[i].jointIndex == baseParentJointIndex) {
+                    if (jointChainInfoOut.jointInfoVec[i].jointIndex == baseParentJointIndex) {
                         baseParentPose = accum;
                     }
                 }
@@ -599,21 +655,16 @@ void AnimInverseKinematics::solveTargetWithCCD(const AnimContext& context, const
                 }
 
                 glm::quat newBaseRelRot = glm::inverse(baseParentPose.rot()) * poleRot * basePose.rot();
-                jointChainInfos[baseChainIndex].relRot = newBaseRelRot;
+                jointChainInfoOut.jointInfoVec[baseChainIndex].rot = newBaseRelRot;
 
                 glm::quat newTopRelRot = glm::inverse(midPose.rot()) * glm::inverse(poleRot) * topPose.rot();
-                jointChainInfos[topChainIndex].relRot = newTopRelRot;
+                jointChainInfoOut.jointInfoVec[topChainIndex].rot = newTopRelRot;
             }
         }
     }
 
-    for (size_t i = 0; i < chainDepth; i++) {
-        _rotationAccumulators[jointChainInfos[i].jointIndex].add(jointChainInfos[i].relRot, jointChainInfos[i].weight);
-        _translationAccumulators[jointChainInfos[i].jointIndex].add(jointChainInfos[i].relTrans, jointChainInfos[i].weight);
-    }
-
     if (debug) {
-        debugDrawIKChain(jointChainInfos, chainDepth, context);
+        debugDrawIKChain(jointChainInfoOut, context);
     }
 }
 
@@ -628,7 +679,7 @@ static CubicHermiteSplineFunctorWithArcLength computeSplineFromTipAndBase(const
 }
 
 // pre-compute information about each joint influeced by this spline IK target.
-void AnimInverseKinematics::computeSplineJointInfosForIKTarget(const AnimContext& context, const IKTarget& target) {
+void AnimInverseKinematics::computeAndCacheSplineJointInfosForIKTarget(const AnimContext& context, const IKTarget& target) const {
     std::vector<SplineJointInfo> splineJointInfoVec;
 
     // build spline between the default poses.
@@ -681,13 +732,13 @@ void AnimInverseKinematics::computeSplineJointInfosForIKTarget(const AnimContext
     _splineJointInfoMap[target.getIndex()] = splineJointInfoVec;
 }
 
-const std::vector<AnimInverseKinematics::SplineJointInfo>* AnimInverseKinematics::findOrCreateSplineJointInfo(const AnimContext& context, const IKTarget& target) {
+const std::vector<AnimInverseKinematics::SplineJointInfo>* AnimInverseKinematics::findOrCreateSplineJointInfo(const AnimContext& context, const IKTarget& target) const {
     // find or create splineJointInfo for this target
     auto iter = _splineJointInfoMap.find(target.getIndex());
     if (iter != _splineJointInfoMap.end()) {
         return &(iter->second);
     } else {
-        computeSplineJointInfosForIKTarget(context, target);
+        computeAndCacheSplineJointInfosForIKTarget(context, target);
         auto iter = _splineJointInfoMap.find(target.getIndex());
         if (iter != _splineJointInfoMap.end()) {
             return &(iter->second);
@@ -697,10 +748,8 @@ const std::vector<AnimInverseKinematics::SplineJointInfo>* AnimInverseKinematics
     return nullptr;
 }
 
-void AnimInverseKinematics::solveTargetWithSpline(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses, bool debug) {
-
-    const size_t MAX_CHAIN_DEPTH = 30;
-    JointChainInfo jointChainInfos[MAX_CHAIN_DEPTH];
+void AnimInverseKinematics::solveTargetWithSpline(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses,
+                                                  bool debug, JointChainInfo& jointChainInfoOut) const {
 
     const int baseIndex = _hipsIndex;
 
@@ -720,7 +769,7 @@ void AnimInverseKinematics::solveTargetWithSpline(const AnimContext& context, co
 
     // This prevents the rotation interpolation from rotating the wrong physical way (but correct mathematical way)
     // when the head is arched backwards very far.
-    glm::quat halfRot = glm::normalize(glm::lerp(basePose.rot(), tipPose.rot(), 0.5f));
+    glm::quat halfRot = safeLerp(basePose.rot(), tipPose.rot(), 0.5f);
     if (glm::dot(halfRot * Vectors::UNIT_Z, basePose.rot() * Vectors::UNIT_Z) < 0.0f) {
         tipPose.rot() = -tipPose.rot();
     }
@@ -743,7 +792,7 @@ void AnimInverseKinematics::solveTargetWithSpline(const AnimContext& context, co
             if (target.getIndex() == _headIndex) {
                 rotT = t * t;
             }
-            glm::quat twistRot = glm::normalize(glm::lerp(basePose.rot(), tipPose.rot(), rotT));
+            glm::quat twistRot = safeLerp(basePose.rot(), tipPose.rot(), rotT);
 
             // compute the rotation by using the derivative of the spline as the y-axis, and the twistRot x-axis
             glm::vec3 y = glm::normalize(spline.d(t));
@@ -783,19 +832,14 @@ void AnimInverseKinematics::solveTargetWithSpline(const AnimContext& context, co
                 }
             }
 
-            jointChainInfos[i] = { relPose.rot(), relPose.trans(), target.getWeight(), splineJointInfo.jointIndex, constrained };
+            jointChainInfoOut.jointInfoVec[i] = { relPose.rot(), relPose.trans(), splineJointInfo.jointIndex, constrained };
 
             parentAbsPose = flexedAbsPose;
         }
     }
 
-    for (size_t i = 0; i < splineJointInfoVec->size(); i++) {
-        _rotationAccumulators[jointChainInfos[i].jointIndex].add(jointChainInfos[i].relRot, jointChainInfos[i].weight);
-        _translationAccumulators[jointChainInfos[i].jointIndex].add(jointChainInfos[i].relTrans, jointChainInfos[i].weight);
-    }
-
     if (debug) {
-        debugDrawIKChain(jointChainInfos, splineJointInfoVec->size(), context);
+        debugDrawIKChain(jointChainInfoOut, context);
     }
 }
 
@@ -806,6 +850,24 @@ const AnimPoseVec& AnimInverseKinematics::evaluate(const AnimVariantMap& animVar
     return _relativePoses;
 }
 
+AnimPose AnimInverseKinematics::applyHipsOffset() const {
+    glm::vec3 hipsOffset = _hipsOffset;
+    AnimPose relHipsPose = _relativePoses[_hipsIndex];
+    float offsetLength = glm::length(hipsOffset);
+    const float MIN_HIPS_OFFSET_LENGTH = 0.03f;
+    if (offsetLength > MIN_HIPS_OFFSET_LENGTH) {
+        float scaleFactor = ((offsetLength - MIN_HIPS_OFFSET_LENGTH) / offsetLength);
+        glm::vec3 scaledHipsOffset = scaleFactor * hipsOffset;
+        if (_hipsParentIndex == -1) {
+            relHipsPose.trans() = _relativePoses[_hipsIndex].trans() + scaledHipsOffset;
+        } else {
+            AnimPose absHipsPose = _skeleton->getAbsolutePose(_hipsIndex, _relativePoses);
+            absHipsPose.trans() += scaledHipsOffset;
+            relHipsPose = _skeleton->getAbsolutePose(_hipsParentIndex, _relativePoses).inverse() * absHipsPose;
+        }
+    }
+    return relHipsPose;
+}
 
 //virtual
 const AnimPoseVec& AnimInverseKinematics::overlay(const AnimVariantMap& animVars, const AnimContext& context, float dt, Triggers& triggersOut, const AnimPoseVec& underPoses) {
@@ -850,33 +912,88 @@ const AnimPoseVec& AnimInverseKinematics::overlay(const AnimVariantMap& animVars
             _relativePoses = underPoses;
         } else {
 
+            JointChainInfoVec jointChainInfoVec(targets.size());
+            {
+                PROFILE_RANGE_EX(simulation_animation, "ik/jointChainInfo", 0xffff00ff, 0);
+
+                // initialize a new jointChainInfoVec, this will hold the results for solving each ik chain.
+                JointInfo defaultJointInfo = { glm::quat(), glm::vec3(), -1, false };
+                for (size_t i = 0; i < targets.size(); i++) {
+                    size_t chainDepth = (size_t)_skeleton->getChainDepth(targets[i].getIndex());
+                    jointChainInfoVec[i].jointInfoVec.reserve(chainDepth);
+                    jointChainInfoVec[i].target = targets[i];
+                    int index = targets[i].getIndex();
+                    for (size_t j = 0; j < chainDepth; j++) {
+                        jointChainInfoVec[i].jointInfoVec.push_back(defaultJointInfo);
+                        jointChainInfoVec[i].jointInfoVec[j].jointIndex = index;
+                        index = _skeleton->getParentIndex(index);
+                    }
+                }
+
+                // identify joint chains that have changed types this frame.
+                _prevJointChainInfoVec.resize(jointChainInfoVec.size());
+                for (size_t i = 0; i < _prevJointChainInfoVec.size(); i++) {
+                    if (_prevJointChainInfoVec[i].timer <= 0.0f &&
+                        (jointChainInfoVec[i].target.getType() != _prevJointChainInfoVec[i].target.getType() ||
+                         jointChainInfoVec[i].target.getPoleVectorEnabled() != _prevJointChainInfoVec[i].target.getPoleVectorEnabled())) {
+                        _prevJointChainInfoVec[i].timer = JOINT_CHAIN_INTERP_TIME;
+                    }
+                }
+            }
+
             {
                 PROFILE_RANGE_EX(simulation_animation, "ik/shiftHips", 0xffff00ff, 0);
 
-                if (_hipsTargetIndex >= 0 && _hipsTargetIndex < (int)targets.size()) {
+                if (_hipsTargetIndex >= 0) {
+                    assert(_hipsTargetIndex < (int)targets.size());
+
                     // slam the hips to match the _hipsTarget
+
                     AnimPose absPose = targets[_hipsTargetIndex].getPose();
+
                     int parentIndex = _skeleton->getParentIndex(targets[_hipsTargetIndex].getIndex());
-                    if (parentIndex != -1) {
-                        _relativePoses[_hipsIndex] = _skeleton->getAbsolutePose(parentIndex, _relativePoses).inverse() * absPose;
-                    } else {
-                        _relativePoses[_hipsIndex] = absPose;
+                    AnimPose parentAbsPose = _skeleton->getAbsolutePose(parentIndex, _relativePoses);
+
+                    // do smooth interpolation of hips, if necessary.
+                    if (_prevJointChainInfoVec[_hipsTargetIndex].timer > 0.0f && _prevJointChainInfoVec[_hipsTargetIndex].jointInfoVec.size() > 0) {
+                        float alpha = (JOINT_CHAIN_INTERP_TIME - _prevJointChainInfoVec[_hipsTargetIndex].timer) / JOINT_CHAIN_INTERP_TIME;
+
+                        auto& info = _prevJointChainInfoVec[_hipsTargetIndex].jointInfoVec[0];
+                        AnimPose prevHipsRelPose(info.rot, info.trans);
+                        AnimPose prevHipsAbsPose = parentAbsPose * prevHipsRelPose;
+                        ::blend(1, &prevHipsAbsPose, &absPose, alpha, &absPose);
                     }
-                } else {
+
+                    _relativePoses[_hipsIndex] = parentAbsPose.inverse() * absPose;
+                    _relativePoses[_hipsIndex].scale() = glm::vec3(1.0f);
+                    _hipsOffset = Vectors::ZERO;
+
+                } else if (_hipsIndex >= 0) {
+
                     // if there is no hips target, shift hips according to the _hipsOffset from the previous frame
-                    float offsetLength = glm::length(_hipsOffset);
-                    const float MIN_HIPS_OFFSET_LENGTH = 0.03f;
-                    if (offsetLength > MIN_HIPS_OFFSET_LENGTH && _hipsIndex >= 0) {
-                        float scaleFactor = ((offsetLength - MIN_HIPS_OFFSET_LENGTH) / offsetLength);
-                        glm::vec3 hipsOffset = scaleFactor * _hipsOffset;
-                        if (_hipsParentIndex == -1) {
-                            _relativePoses[_hipsIndex].trans() = _relativePoses[_hipsIndex].trans() + hipsOffset;
-                        } else {
-                            auto absHipsPose = _skeleton->getAbsolutePose(_hipsIndex, _relativePoses);
-                            absHipsPose.trans() += hipsOffset;
-                            _relativePoses[_hipsIndex] = _skeleton->getAbsolutePose(_hipsParentIndex, _relativePoses).inverse() * absHipsPose;
+                    AnimPose relHipsPose = applyHipsOffset();
+
+                    // determine if we should begin interpolating the hips.
+                    for (size_t i = 0; i < targets.size(); i++) {
+                        if (_prevJointChainInfoVec[i].target.getIndex() == _hipsIndex) {
+                            if (_prevJointChainInfoVec[i].timer > 0.0f) {
+                                // smoothly lerp in hipsOffset
+                                float alpha = (JOINT_CHAIN_INTERP_TIME - _prevJointChainInfoVec[i].timer) / JOINT_CHAIN_INTERP_TIME;
+                                AnimPose prevRelHipsPose(_prevJointChainInfoVec[i].jointInfoVec[0].rot, _prevJointChainInfoVec[i].jointInfoVec[0].trans);
+                                ::blend(1, &prevRelHipsPose, &relHipsPose, alpha, &relHipsPose);
+                            }
+                            break;
                         }
                     }
+
+                    _relativePoses[_hipsIndex] = relHipsPose;
+                }
+
+                // if there is an active jointChainInfo for the hips store the post shifted hips into it.
+                // This is so we have a valid pose to interplate from when the hips target is disabled.
+                if (_hipsTargetIndex >= 0) {
+                    jointChainInfoVec[_hipsTargetIndex].jointInfoVec[0].rot = _relativePoses[_hipsIndex].rot();
+                    jointChainInfoVec[_hipsTargetIndex].jointInfoVec[0].trans = _relativePoses[_hipsIndex].trans();
                 }
 
                 // update all HipsRelative targets to account for the hips shift/ik target.
@@ -920,15 +1037,14 @@ const AnimPoseVec& AnimInverseKinematics::overlay(const AnimVariantMap& animVars
 
             {
                 PROFILE_RANGE_EX(simulation_animation, "ik/ccd", 0xffff00ff, 0);
+
                 preconditionRelativePosesToAvoidLimbLock(context, targets);
-                solve(context, targets);
+                solve(context, targets, dt, jointChainInfoVec);
             }
 
             if (_hipsTargetIndex < 0) {
                 PROFILE_RANGE_EX(simulation_animation, "ik/measureHipsOffset", 0xffff00ff, 0);
-                computeHipsOffset(targets, underPoses, dt);
-            } else {
-                _hipsOffset = Vectors::ZERO;
+                _hipsOffset = computeHipsOffset(targets, underPoses, dt, _hipsOffset);
             }
         }
 
@@ -937,23 +1053,15 @@ const AnimPoseVec& AnimInverseKinematics::overlay(const AnimVariantMap& animVars
         }
     }
 
-    if (_leftHandIndex > -1) {
-        _uncontrolledLeftHandPose = _skeleton->getAbsolutePose(_leftHandIndex, underPoses);
-    }
-    if (_rightHandIndex > -1) {
-        _uncontrolledRightHandPose = _skeleton->getAbsolutePose(_rightHandIndex, underPoses);
-    }
-    if (_hipsIndex > -1) {
-        _uncontrolledHipsPose = _skeleton->getAbsolutePose(_hipsIndex, underPoses);
-    }
-
     return _relativePoses;
 }
 
-void AnimInverseKinematics::computeHipsOffset(const std::vector<IKTarget>& targets, const AnimPoseVec& underPoses, float dt) {
+glm::vec3 AnimInverseKinematics::computeHipsOffset(const std::vector<IKTarget>& targets, const AnimPoseVec& underPoses, float dt, glm::vec3 prevHipsOffset) const {
+
     // measure new _hipsOffset for next frame
     // by looking for discrepancies between where a targeted endEffector is
     // and where it wants to be (after IK solutions are done)
+    glm::vec3 hipsOffset = prevHipsOffset;
     glm::vec3 newHipsOffset = Vectors::ZERO;
     for (auto& target: targets) {
         int targetIndex = target.getIndex();
@@ -969,9 +1077,9 @@ void AnimInverseKinematics::computeHipsOffset(const std::vector<IKTarget>& targe
             } else if (target.getType() == IKTarget::Type::HmdHead) {
                 // we want to shift the hips to bring the head to its designated position
                 glm::vec3 actual = _skeleton->getAbsolutePose(_headIndex, _relativePoses).trans();
-                _hipsOffset += target.getTranslation() - actual;
+                hipsOffset += target.getTranslation() - actual;
                 // and ignore all other targets
-                newHipsOffset = _hipsOffset;
+                newHipsOffset = hipsOffset;
                 break;
             } else if (target.getType() == IKTarget::Type::RotationAndPosition) {
                 glm::vec3 actualPosition = _skeleton->getAbsolutePose(targetIndex, _relativePoses).trans();
@@ -991,16 +1099,18 @@ void AnimInverseKinematics::computeHipsOffset(const std::vector<IKTarget>& targe
         }
     }
 
-    // smooth transitions by relaxing _hipsOffset toward the new value
+    // smooth transitions by relaxing hipsOffset toward the new value
     const float HIPS_OFFSET_SLAVE_TIMESCALE = 0.10f;
     float tau = dt < HIPS_OFFSET_SLAVE_TIMESCALE ?  dt / HIPS_OFFSET_SLAVE_TIMESCALE : 1.0f;
-    _hipsOffset += (newHipsOffset - _hipsOffset) * tau;
+    hipsOffset += (newHipsOffset - hipsOffset) * tau;
 
     // clamp the hips offset
-    float hipsOffsetLength = glm::length(_hipsOffset);
+    float hipsOffsetLength = glm::length(hipsOffset);
     if (hipsOffsetLength > _maxHipsOffsetLength) {
-        _hipsOffset *= _maxHipsOffsetLength / hipsOffsetLength;
+        hipsOffset *= _maxHipsOffsetLength / hipsOffsetLength;
     }
+
+    return hipsOffset;
 }
 
 void AnimInverseKinematics::setMaxHipsOffsetLength(float maxLength) {
@@ -1414,8 +1524,6 @@ void AnimInverseKinematics::setSkeletonInternal(AnimSkeleton::ConstPointer skele
         targetVar.jointIndex = -1;
     }
 
-    _maxTargetIndex = -1;
-
     for (auto& accumulator: _rotationAccumulators) {
         accumulator.clearAndClean();
     }
@@ -1446,10 +1554,6 @@ void AnimInverseKinematics::setSkeletonInternal(AnimSkeleton::ConstPointer skele
         _leftHandIndex = -1;
         _rightHandIndex = -1;
     }
-
-    _uncontrolledLeftHandPose = AnimPose();
-    _uncontrolledRightHandPose = AnimPose();
-    _uncontrolledHipsPose = AnimPose();
 }
 
 static glm::vec3 sphericalToCartesian(float phi, float theta) {
@@ -1495,14 +1599,14 @@ void AnimInverseKinematics::debugDrawRelativePoses(const AnimContext& context) c
     }
 }
 
-void AnimInverseKinematics::debugDrawIKChain(JointChainInfo* jointChainInfos, size_t numJointChainInfos, const AnimContext& context) const {
+void AnimInverseKinematics::debugDrawIKChain(const JointChainInfo& jointChainInfo, const AnimContext& context) const {
     AnimPoseVec poses = _relativePoses;
 
     // copy debug joint rotations into the relative poses
-    for (size_t i = 0; i < numJointChainInfos; i++) {
-        const JointChainInfo& info = jointChainInfos[i];
-        poses[info.jointIndex].rot() = info.relRot;
-        poses[info.jointIndex].trans() = info.relTrans;
+    for (size_t i = 0; i < jointChainInfo.jointInfoVec.size(); i++) {
+        const JointInfo& info = jointChainInfo.jointInfoVec[i];
+        poses[info.jointIndex].rot() = info.rot;
+        poses[info.jointIndex].trans() = info.trans;
     }
 
     // convert relative poses to absolute
@@ -1519,9 +1623,9 @@ void AnimInverseKinematics::debugDrawIKChain(JointChainInfo* jointChainInfos, si
     // draw each pose
     for (int i = 0; i < (int)poses.size(); i++) {
         int parentIndex = _skeleton->getParentIndex(i);
-        JointChainInfo* jointInfo = nullptr;
-        JointChainInfo* parentJointInfo = nullptr;
-        lookupJointChainInfo(jointChainInfos, numJointChainInfos, i, parentIndex, &jointInfo, &parentJointInfo);
+        const JointInfo* jointInfo = nullptr;
+        const JointInfo* parentJointInfo = nullptr;
+        lookupJointInfo(jointChainInfo, i, parentIndex, &jointInfo, &parentJointInfo);
         if (jointInfo && parentJointInfo) {
 
             // transform local axes into world space.
@@ -1608,7 +1712,7 @@ void AnimInverseKinematics::debugDrawConstraints(const AnimContext& context) con
 
                     const int NUM_SWING_STEPS = 10;
                     for (int i = 0; i < NUM_SWING_STEPS + 1; i++) {
-                        glm::quat rot = glm::normalize(glm::lerp(minRot, maxRot, i * (1.0f / NUM_SWING_STEPS)));
+                        glm::quat rot = safeLerp(minRot, maxRot, i * (1.0f / NUM_SWING_STEPS));
                         glm::vec3 axis = transformVectorFast(geomToWorldMatrix, parentAbsRot * rot * refRot * Vectors::UNIT_Y);
                         DebugDraw::getInstance().drawRay(pos, pos + TWIST_LENGTH * axis, CYAN);
                     }
@@ -1626,7 +1730,7 @@ void AnimInverseKinematics::debugDrawConstraints(const AnimContext& context) con
 
                         const int NUM_SWING_STEPS = 10;
                         for (int i = 0; i < NUM_SWING_STEPS + 1; i++) {
-                            glm::quat rot = glm::normalize(glm::lerp(minRot, maxRot, i * (1.0f / NUM_SWING_STEPS)));
+                            glm::quat rot = safeLerp(minRot, maxRot, i * (1.0f / NUM_SWING_STEPS));
                             glm::vec3 axis = transformVectorFast(geomToWorldMatrix, parentAbsRot * rot * refRot * Vectors::UNIT_X);
                             DebugDraw::getInstance().drawRay(pos, pos + TWIST_LENGTH * axis, CYAN);
                         }
@@ -1666,10 +1770,9 @@ void AnimInverseKinematics::blendToPoses(const AnimPoseVec& targetPoses, const A
     // relax toward poses
     int numJoints = (int)_relativePoses.size();
     for (int i = 0; i < numJoints; ++i) {
-        float dotSign = copysignf(1.0f, glm::dot(_relativePoses[i].rot(), targetPoses[i].rot()));
         if (_rotationAccumulators[i].isDirty()) {
             // this joint is affected by IK --> blend toward the targetPoses rotation
-            _relativePoses[i].rot() = glm::normalize(glm::lerp(_relativePoses[i].rot(), dotSign * targetPoses[i].rot(), blendFactor));
+            _relativePoses[i].rot() = safeLerp(_relativePoses[i].rot(), targetPoses[i].rot(), blendFactor);
         } else {
             // this joint is NOT affected by IK --> slam to underPoses rotation
             _relativePoses[i].rot() = underPoses[i].rot();
diff --git a/libraries/animation/src/AnimInverseKinematics.h b/libraries/animation/src/AnimInverseKinematics.h
index d473ae3698..7f7640aa24 100644
--- a/libraries/animation/src/AnimInverseKinematics.h
+++ b/libraries/animation/src/AnimInverseKinematics.h
@@ -26,14 +26,21 @@ class RotationConstraint;
 class AnimInverseKinematics : public AnimNode {
 public:
 
-    struct JointChainInfo {
-        glm::quat relRot;
-        glm::vec3 relTrans;
-        float weight;
+    struct JointInfo {
+        glm::quat rot;
+        glm::vec3 trans;
         int jointIndex;
         bool constrained;
     };
 
+    struct JointChainInfo {
+        std::vector<JointInfo> jointInfoVec;
+        IKTarget target;
+        float timer { 0.0f };
+    };
+
+    using JointChainInfoVec = std::vector<JointChainInfo>;
+
     explicit AnimInverseKinematics(const QString& id);
     virtual ~AnimInverseKinematics() override;
 
@@ -66,23 +73,22 @@ public:
     void setSolutionSource(SolutionSource solutionSource) { _solutionSource = solutionSource; }
     void setSolutionSourceVar(const QString& solutionSourceVar) { _solutionSourceVar = solutionSourceVar; }
 
-    const AnimPose& getUncontrolledLeftHandPose() { return _uncontrolledLeftHandPose; }
-    const AnimPose& getUncontrolledRightHandPose() { return _uncontrolledRightHandPose; }
-    const AnimPose& getUncontrolledHipPose() { return _uncontrolledHipsPose; }
-
 protected:
     void computeTargets(const AnimVariantMap& animVars, std::vector<IKTarget>& targets, const AnimPoseVec& underPoses);
-    void solve(const AnimContext& context, const std::vector<IKTarget>& targets);
-    void solveTargetWithCCD(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses, bool debug);
-    void solveTargetWithSpline(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses, bool debug);
+    void solve(const AnimContext& context, const std::vector<IKTarget>& targets, float dt, JointChainInfoVec& jointChainInfoVec);
+    void solveTargetWithCCD(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses,
+                            bool debug, JointChainInfo& jointChainInfoOut) const;
+    void solveTargetWithSpline(const AnimContext& context, const IKTarget& target, const AnimPoseVec& absolutePoses,
+                               bool debug, JointChainInfo& jointChainInfoOut) const;
     virtual void setSkeletonInternal(AnimSkeleton::ConstPointer skeleton) override;
-    void debugDrawIKChain(JointChainInfo* jointChainInfos, size_t numJointChainInfos, const AnimContext& context) const;
+    void debugDrawIKChain(const JointChainInfo& jointChainInfo, const AnimContext& context) const;
     void debugDrawRelativePoses(const AnimContext& context) const;
     void debugDrawConstraints(const AnimContext& context) const;
     void debugDrawSpineSplines(const AnimContext& context, const std::vector<IKTarget>& targets) const;
     void initRelativePosesFromSolutionSource(SolutionSource solutionSource, const AnimPoseVec& underPose);
     void blendToPoses(const AnimPoseVec& targetPoses, const AnimPoseVec& underPose, float blendFactor);
     void preconditionRelativePosesToAvoidLimbLock(const AnimContext& context, const std::vector<IKTarget>& targets);
+    AnimPose applyHipsOffset() const;
 
     // used to pre-compute information about each joint influeced by a spline IK target.
     struct SplineJointInfo {
@@ -91,8 +97,8 @@ protected:
         AnimPose offsetPose;  // local offset from the spline to the joint.
     };
 
-    void computeSplineJointInfosForIKTarget(const AnimContext& context, const IKTarget& target);
-    const std::vector<SplineJointInfo>* findOrCreateSplineJointInfo(const AnimContext& context, const IKTarget& target);
+    void computeAndCacheSplineJointInfosForIKTarget(const AnimContext& context, const IKTarget& target) const;
+    const std::vector<SplineJointInfo>* findOrCreateSplineJointInfo(const AnimContext& context, const IKTarget& target) const;
 
     // for AnimDebugDraw rendering
     virtual const AnimPoseVec& getPosesInternal() const override { return _relativePoses; }
@@ -101,7 +107,7 @@ protected:
     void clearConstraints();
     void initConstraints();
     void initLimitCenterPoses();
-    void computeHipsOffset(const std::vector<IKTarget>& targets, const AnimPoseVec& underPoses, float dt);
+    glm::vec3 computeHipsOffset(const std::vector<IKTarget>& targets, const AnimPoseVec& underPoses, float dt, glm::vec3 prevHipsOffset) const;
 
     // no copies
     AnimInverseKinematics(const AnimInverseKinematics&) = delete;
@@ -136,7 +142,7 @@ protected:
     AnimPoseVec _relativePoses; // current relative poses
     AnimPoseVec _limitCenterPoses;  // relative
 
-    std::map<int, std::vector<SplineJointInfo>> _splineJointInfoMap;
+    mutable std::map<int, std::vector<SplineJointInfo>> _splineJointInfoMap;
 
     // experimental data for moving hips during IK
     glm::vec3 _hipsOffset { Vectors::ZERO };
@@ -148,18 +154,12 @@ protected:
     int _leftHandIndex { -1 };
     int _rightHandIndex { -1 };
 
-    // _maxTargetIndex is tracked to help optimize the recalculation of absolute poses
-    // during the the cyclic coordinate descent algorithm
-    int _maxTargetIndex { 0 };
-
     float _maxErrorOnLastSolve { FLT_MAX };
     bool _previousEnableDebugIKTargets { false };
     SolutionSource _solutionSource { SolutionSource::RelaxToUnderPoses };
     QString _solutionSourceVar;
 
-    AnimPose _uncontrolledLeftHandPose { AnimPose() };
-    AnimPose _uncontrolledRightHandPose { AnimPose() };
-    AnimPose _uncontrolledHipsPose { AnimPose() };
+    JointChainInfoVec _prevJointChainInfoVec;
 };
 
 #endif // hifi_AnimInverseKinematics_h
diff --git a/libraries/animation/src/AnimSkeleton.cpp b/libraries/animation/src/AnimSkeleton.cpp
index 062e016660..804ffb0583 100644
--- a/libraries/animation/src/AnimSkeleton.cpp
+++ b/libraries/animation/src/AnimSkeleton.cpp
@@ -42,6 +42,20 @@ int AnimSkeleton::getNumJoints() const {
     return _jointsSize;
 }
 
+int AnimSkeleton::getChainDepth(int jointIndex) const {
+    if (jointIndex >= 0) {
+        int chainDepth = 0;
+        int index = jointIndex;
+        do {
+            chainDepth++;
+            index = _joints[index].parentIndex;
+        } while (index != -1);
+        return chainDepth;
+    } else {
+        return 0;
+    }
+}
+
 const AnimPose& AnimSkeleton::getAbsoluteBindPose(int jointIndex) const {
     return _absoluteBindPoses[jointIndex];
 }
diff --git a/libraries/animation/src/AnimSkeleton.h b/libraries/animation/src/AnimSkeleton.h
index 6315f2d62b..99c9a148f7 100644
--- a/libraries/animation/src/AnimSkeleton.h
+++ b/libraries/animation/src/AnimSkeleton.h
@@ -28,6 +28,7 @@ public:
     int nameToJointIndex(const QString& jointName) const;
     const QString& getJointName(int jointIndex) const;
     int getNumJoints() const;
+    int getChainDepth(int jointIndex) const;
 
     // absolute pose, not relative to parent
     const AnimPose& getAbsoluteBindPose(int jointIndex) const;
diff --git a/libraries/animation/src/AnimUtil.cpp b/libraries/animation/src/AnimUtil.cpp
index a4659f1e76..bcf30642e8 100644
--- a/libraries/animation/src/AnimUtil.cpp
+++ b/libraries/animation/src/AnimUtil.cpp
@@ -28,7 +28,7 @@ void blend(size_t numPoses, const AnimPose* a, const AnimPose* b, float alpha, A
         }
 
         result[i].scale() = lerp(aPose.scale(), bPose.scale(), alpha);
-        result[i].rot() = glm::normalize(glm::lerp(aPose.rot(), q2, alpha));
+        result[i].rot() = safeLerp(aPose.rot(), bPose.rot(), alpha);
         result[i].trans() = lerp(aPose.trans(), bPose.trans(), alpha);
     }
 }
diff --git a/libraries/animation/src/AnimUtil.h b/libraries/animation/src/AnimUtil.h
index 055fd630eb..d215fdc654 100644
--- a/libraries/animation/src/AnimUtil.h
+++ b/libraries/animation/src/AnimUtil.h
@@ -21,4 +21,14 @@ glm::quat averageQuats(size_t numQuats, const glm::quat* quats);
 float accumulateTime(float startFrame, float endFrame, float timeScale, float currentFrame, float dt, bool loopFlag,
                      const QString& id, AnimNode::Triggers& triggersOut);
 
+inline glm::quat safeLerp(const glm::quat& a, const glm::quat& b, float alpha) {
+    // adjust signs if necessary
+    glm::quat bTemp = b;
+    float dot = glm::dot(a, bTemp);
+    if (dot < 0.0f) {
+        bTemp = -bTemp;
+    }
+    return glm::normalize(glm::lerp(a, bTemp, alpha));
+}
+
 #endif
diff --git a/libraries/animation/src/IKTarget.h b/libraries/animation/src/IKTarget.h
index 5567539659..325a1b40b6 100644
--- a/libraries/animation/src/IKTarget.h
+++ b/libraries/animation/src/IKTarget.h
@@ -56,8 +56,8 @@ private:
     glm::vec3 _poleReferenceVector;
     bool _poleVectorEnabled { false };
     int _index { -1 };
-    Type _type { Type::RotationAndPosition };
-    float _weight;
+    Type _type { Type::Unknown };
+    float _weight { 0.0f };
     float _flexCoefficients[MAX_FLEX_COEFFICIENTS];
     size_t _numFlexCoefficients;
 };
diff --git a/libraries/animation/src/Rig.cpp b/libraries/animation/src/Rig.cpp
index 6ebb68773f..fc0ca73c96 100644
--- a/libraries/animation/src/Rig.cpp
+++ b/libraries/animation/src/Rig.cpp
@@ -1115,36 +1115,13 @@ void Rig::updateHands(bool leftHandEnabled, bool rightHandEnabled, bool hipsEnab
     const glm::vec3 bodyCapsuleEnd = bodyCapsuleCenter + glm::vec3(0, bodyCapsuleHalfHeight, 0);
 
     const float HAND_RADIUS = 0.05f;
-
-    const float RELAX_DURATION = 0.6f;
-    const float CONTROL_DURATION = 0.4f;
-    const bool TO_CONTROLLED = true;
-    const bool FROM_CONTROLLED = false;
-    const bool LEFT_HAND = true;
-    const bool RIGHT_HAND = false;
-
     const float ELBOW_POLE_VECTOR_BLEND_FACTOR = 0.95f;
 
     if (leftHandEnabled) {
-        if (!_isLeftHandControlled) {
-            _leftHandControlTimeRemaining = CONTROL_DURATION;
-            _isLeftHandControlled = true;
-        }
 
         glm::vec3 handPosition = leftHandPose.trans();
         glm::quat handRotation = leftHandPose.rot();
 
-        if (_leftHandControlTimeRemaining > 0.0f) {
-            // Move hand from non-controlled position to controlled position.
-            _leftHandControlTimeRemaining = std::max(_leftHandControlTimeRemaining - dt, 0.0f);
-            AnimPose handPose(Vectors::ONE, handRotation, handPosition);
-            if (transitionHandPose(_leftHandControlTimeRemaining, CONTROL_DURATION, handPose,
-                                   LEFT_HAND, TO_CONTROLLED, handPose)) {
-                handPosition = handPose.trans();
-                handRotation = handPose.rot();
-            }
-        }
-
         if (!hipsEnabled) {
             // prevent the hand IK targets from intersecting the body capsule
             glm::vec3 displacement;
@@ -1157,9 +1134,6 @@ void Rig::updateHands(bool leftHandEnabled, bool rightHandEnabled, bool hipsEnab
         _animVars.set("leftHandRotation", handRotation);
         _animVars.set("leftHandType", (int)IKTarget::Type::RotationAndPosition);
 
-        _lastLeftHandControlledPose = AnimPose(Vectors::ONE, handRotation, handPosition);
-        _isLeftHandControlled = true;
-
         // compute pole vector
         int handJointIndex = _animSkeleton->nameToJointIndex("LeftHand");
         int armJointIndex = _animSkeleton->nameToJointIndex("LeftArm");
@@ -1187,47 +1161,17 @@ void Rig::updateHands(bool leftHandEnabled, bool rightHandEnabled, bool hipsEnab
         _prevLeftHandPoleVectorValid = false;
         _animVars.set("leftHandPoleVectorEnabled", false);
 
-        if (_isLeftHandControlled) {
-            _leftHandRelaxTimeRemaining = RELAX_DURATION;
-            _isLeftHandControlled = false;
-        }
+        _animVars.unset("leftHandPosition");
+        _animVars.unset("leftHandRotation");
+        _animVars.set("leftHandType", (int)IKTarget::Type::HipsRelativeRotationAndPosition);
 
-        if (_leftHandRelaxTimeRemaining > 0.0f) {
-            // Move hand from controlled position to non-controlled position.
-            _leftHandRelaxTimeRemaining = std::max(_leftHandRelaxTimeRemaining - dt, 0.0f);
-            AnimPose handPose;
-            if (transitionHandPose(_leftHandRelaxTimeRemaining, RELAX_DURATION, _lastLeftHandControlledPose,
-                                   LEFT_HAND, FROM_CONTROLLED, handPose)) {
-                _animVars.set("leftHandPosition", handPose.trans());
-                _animVars.set("leftHandRotation", handPose.rot());
-                _animVars.set("leftHandType", (int)IKTarget::Type::RotationAndPosition);
-            }
-        } else {
-            _animVars.unset("leftHandPosition");
-            _animVars.unset("leftHandRotation");
-            _animVars.set("leftHandType", (int)IKTarget::Type::HipsRelativeRotationAndPosition);
-        }
     }
 
     if (rightHandEnabled) {
-        if (!_isRightHandControlled) {
-            _rightHandControlTimeRemaining = CONTROL_DURATION;
-            _isRightHandControlled = true;
-        }
 
         glm::vec3 handPosition = rightHandPose.trans();
         glm::quat handRotation = rightHandPose.rot();
 
-        if (_rightHandControlTimeRemaining > 0.0f) {
-            // Move hand from non-controlled position to controlled position.
-            _rightHandControlTimeRemaining = std::max(_rightHandControlTimeRemaining - dt, 0.0f);
-            AnimPose handPose(Vectors::ONE, handRotation, handPosition);
-            if (transitionHandPose(_rightHandControlTimeRemaining, CONTROL_DURATION, handPose, RIGHT_HAND, TO_CONTROLLED, handPose)) {
-                handPosition = handPose.trans();
-                handRotation = handPose.rot();
-            }
-        }
-
         if (!hipsEnabled) {
             // prevent the hand IK targets from intersecting the body capsule
             glm::vec3 displacement;
@@ -1240,9 +1184,6 @@ void Rig::updateHands(bool leftHandEnabled, bool rightHandEnabled, bool hipsEnab
         _animVars.set("rightHandRotation", handRotation);
         _animVars.set("rightHandType", (int)IKTarget::Type::RotationAndPosition);
 
-        _lastRightHandControlledPose = AnimPose(Vectors::ONE, handRotation, handPosition);
-        _isRightHandControlled = true;
-
         // compute pole vector
         int handJointIndex = _animSkeleton->nameToJointIndex("RightHand");
         int armJointIndex = _animSkeleton->nameToJointIndex("RightArm");
@@ -1270,25 +1211,9 @@ void Rig::updateHands(bool leftHandEnabled, bool rightHandEnabled, bool hipsEnab
         _prevRightHandPoleVectorValid = false;
         _animVars.set("rightHandPoleVectorEnabled", false);
 
-        if (_isRightHandControlled) {
-            _rightHandRelaxTimeRemaining = RELAX_DURATION;
-            _isRightHandControlled = false;
-        }
-
-        if (_rightHandRelaxTimeRemaining > 0.0f) {
-            // Move hand from controlled position to non-controlled position.
-            _rightHandRelaxTimeRemaining = std::max(_rightHandRelaxTimeRemaining - dt, 0.0f);
-            AnimPose handPose;
-            if (transitionHandPose(_rightHandRelaxTimeRemaining, RELAX_DURATION, _lastRightHandControlledPose, RIGHT_HAND, FROM_CONTROLLED, handPose)) {
-                _animVars.set("rightHandPosition", handPose.trans());
-                _animVars.set("rightHandRotation", handPose.rot());
-                _animVars.set("rightHandType", (int)IKTarget::Type::RotationAndPosition);
-            }
-        } else {
-            _animVars.unset("rightHandPosition");
-            _animVars.unset("rightHandRotation");
-            _animVars.set("rightHandType", (int)IKTarget::Type::HipsRelativeRotationAndPosition);
-        }
+        _animVars.unset("rightHandPosition");
+        _animVars.unset("rightHandRotation");
+        _animVars.set("rightHandType", (int)IKTarget::Type::HipsRelativeRotationAndPosition);
     }
 }
 
@@ -1737,39 +1662,38 @@ void Rig::computeAvatarBoundingCapsule(
     ikNode.setTargetVars("RightFoot", "rightFootPosition", "rightFootRotation",
                          "rightFootType", "rightFootWeight", 1.0f, {},
                          QString(), QString(), QString());
-
-    AnimPose geometryToRig = _modelOffset * _geometryOffset;
-
-    AnimPose hips(glm::vec3(1), glm::quat(), glm::vec3());
+    glm::vec3 hipsPosition(0.0f);
     int hipsIndex = indexOfJoint("Hips");
     if (hipsIndex >= 0) {
-        hips = geometryToRig * _animSkeleton->getAbsoluteBindPose(hipsIndex);
+        hipsPosition = transformPoint(_geometryToRigTransform, _animSkeleton->getAbsoluteDefaultPose(hipsIndex).trans());
     }
     AnimVariantMap animVars;
+    animVars.setRigToGeometryTransform(_rigToGeometryTransform);
     glm::quat handRotation = glm::angleAxis(PI, Vectors::UNIT_X);
-    animVars.set("leftHandPosition", hips.trans());
+    animVars.set("leftHandPosition", hipsPosition);
     animVars.set("leftHandRotation", handRotation);
     animVars.set("leftHandType", (int)IKTarget::Type::RotationAndPosition);
-    animVars.set("rightHandPosition", hips.trans());
+    animVars.set("rightHandPosition", hipsPosition);
     animVars.set("rightHandRotation", handRotation);
     animVars.set("rightHandType", (int)IKTarget::Type::RotationAndPosition);
 
     int rightFootIndex = indexOfJoint("RightFoot");
     int leftFootIndex = indexOfJoint("LeftFoot");
     if (rightFootIndex != -1 && leftFootIndex != -1) {
-        glm::vec3 foot = Vectors::ZERO;
+        glm::vec3 geomFootPosition = glm::vec3(0.0f, _animSkeleton->getAbsoluteDefaultPose(rightFootIndex).trans().y, 0.0f);
+        glm::vec3 footPosition = transformPoint(_geometryToRigTransform, geomFootPosition);
         glm::quat footRotation = glm::angleAxis(0.5f * PI, Vectors::UNIT_X);
-        animVars.set("leftFootPosition", foot);
+        animVars.set("leftFootPosition", footPosition);
         animVars.set("leftFootRotation", footRotation);
         animVars.set("leftFootType", (int)IKTarget::Type::RotationAndPosition);
-        animVars.set("rightFootPosition", foot);
+        animVars.set("rightFootPosition", footPosition);
         animVars.set("rightFootRotation", footRotation);
         animVars.set("rightFootType", (int)IKTarget::Type::RotationAndPosition);
     }
 
     // call overlay twice: once to verify AnimPoseVec joints and again to do the IK
     AnimNode::Triggers triggersOut;
-    AnimContext context(false, false, false, glm::mat4(), glm::mat4());
+    AnimContext context(false, false, false, _geometryToRigTransform, _rigToGeometryTransform);
     float dt = 1.0f; // the value of this does not matter
     ikNode.overlay(animVars, context, dt, triggersOut, _animSkeleton->getRelativeBindPoses());
     AnimPoseVec finalPoses =  ikNode.overlay(animVars, context, dt, triggersOut, _animSkeleton->getRelativeBindPoses());
@@ -1802,34 +1726,13 @@ void Rig::computeAvatarBoundingCapsule(
 
     // compute bounding shape parameters
     // NOTE: we assume that the longest side of totalExtents is the yAxis...
-    glm::vec3 diagonal = (geometryToRig * totalExtents.maximum) - (geometryToRig * totalExtents.minimum);
+    glm::vec3 diagonal = (transformPoint(_geometryToRigTransform, totalExtents.maximum) -
+                          transformPoint(_geometryToRigTransform, totalExtents.minimum));
     // ... and assume the radiusOut is half the RMS of the X and Z sides:
     radiusOut = 0.5f * sqrtf(0.5f * (diagonal.x * diagonal.x + diagonal.z * diagonal.z));
     heightOut = diagonal.y - 2.0f * radiusOut;
 
     glm::vec3 rootPosition = finalPoses[geometry.rootJointIndex].trans();
-    glm::vec3 rigCenter = (geometryToRig * (0.5f * (totalExtents.maximum + totalExtents.minimum)));
-    localOffsetOut = rigCenter - (geometryToRig * rootPosition);
-}
-
-bool Rig::transitionHandPose(float deltaTime, float totalDuration, AnimPose& controlledHandPose, bool isLeftHand,
-                             bool isToControlled, AnimPose& returnHandPose) {
-    auto ikNode = getAnimInverseKinematicsNode();
-    if (ikNode) {
-        float alpha = 1.0f - deltaTime / totalDuration;
-        const AnimPose geometryToRigTransform(_geometryToRigTransform);
-        AnimPose uncontrolledHandPose;
-        if (isLeftHand) {
-            uncontrolledHandPose = geometryToRigTransform * ikNode->getUncontrolledLeftHandPose();
-        } else {
-            uncontrolledHandPose = geometryToRigTransform * ikNode->getUncontrolledRightHandPose();
-        }
-        if (isToControlled) {
-            ::blend(1, &uncontrolledHandPose, &controlledHandPose, alpha, &returnHandPose);
-        } else {
-            ::blend(1, &controlledHandPose, &uncontrolledHandPose, alpha, &returnHandPose);
-        }
-        return true;
-    }
-    return false;
+    glm::vec3 rigCenter = transformPoint(_geometryToRigTransform, (0.5f * (totalExtents.maximum + totalExtents.minimum)));
+    localOffsetOut = rigCenter - transformPoint(_geometryToRigTransform, rootPosition);
 }
diff --git a/libraries/animation/src/Rig.h b/libraries/animation/src/Rig.h
index c17a7b9c8f..5293fa1fe7 100644
--- a/libraries/animation/src/Rig.h
+++ b/libraries/animation/src/Rig.h
@@ -340,18 +340,6 @@ protected:
     int _nextStateHandlerId { 0 };
     QMutex _stateMutex;
 
-    bool transitionHandPose(float deltaTime, float totalDuration, AnimPose& controlledHandPose, bool isLeftHand,
-                            bool isToControlled, AnimPose& returnHandPose);
-
-    bool _isLeftHandControlled { false };
-    bool _isRightHandControlled { false };
-    float _leftHandControlTimeRemaining { 0.0f };
-    float _rightHandControlTimeRemaining { 0.0f };
-    float _leftHandRelaxTimeRemaining { 0.0f };
-    float _rightHandRelaxTimeRemaining { 0.0f };
-    AnimPose _lastLeftHandControlledPose;
-    AnimPose _lastRightHandControlledPose;
-
     glm::vec3 _prevRightFootPoleVector { Vectors::UNIT_Z };
     bool _prevRightFootPoleVectorValid { false };
 
diff --git a/libraries/entities-renderer/src/EntityTreeRenderer.cpp b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
index a8eca41077..475471b0fb 100644
--- a/libraries/entities-renderer/src/EntityTreeRenderer.cpp
+++ b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
@@ -26,6 +26,7 @@
 #include <PerfStat.h>
 #include <SceneScriptingInterface.h>
 #include <ScriptEngine.h>
+#include <HoverOverlayInterface.h>
 
 
 #include "RenderableEntityItem.h"
@@ -452,6 +453,8 @@ RayToEntityIntersectionResult EntityTreeRenderer::findRayIntersectionWorker(cons
 
 void EntityTreeRenderer::connectSignalsToSlots(EntityScriptingInterface* entityScriptingInterface) {
 
+    auto hoverOverlayInterface = DependencyManager::get<HoverOverlayInterface>().data();
+
     connect(this, &EntityTreeRenderer::mousePressOnEntity, entityScriptingInterface, &EntityScriptingInterface::mousePressOnEntity);
     connect(this, &EntityTreeRenderer::mouseMoveOnEntity, entityScriptingInterface, &EntityScriptingInterface::mouseMoveOnEntity);
     connect(this, &EntityTreeRenderer::mouseReleaseOnEntity, entityScriptingInterface, &EntityScriptingInterface::mouseReleaseOnEntity);
@@ -461,8 +464,12 @@ void EntityTreeRenderer::connectSignalsToSlots(EntityScriptingInterface* entityS
     connect(this, &EntityTreeRenderer::clickReleaseOnEntity, entityScriptingInterface, &EntityScriptingInterface::clickReleaseOnEntity);
 
     connect(this, &EntityTreeRenderer::hoverEnterEntity, entityScriptingInterface, &EntityScriptingInterface::hoverEnterEntity);
+    connect(this, &EntityTreeRenderer::hoverEnterEntity, hoverOverlayInterface, &HoverOverlayInterface::createHoverOverlay);
+
     connect(this, &EntityTreeRenderer::hoverOverEntity, entityScriptingInterface, &EntityScriptingInterface::hoverOverEntity);
+
     connect(this, &EntityTreeRenderer::hoverLeaveEntity, entityScriptingInterface, &EntityScriptingInterface::hoverLeaveEntity);
+    connect(this, &EntityTreeRenderer::hoverLeaveEntity, hoverOverlayInterface, &HoverOverlayInterface::destroyHoverOverlay);
 
     connect(this, &EntityTreeRenderer::enterEntity, entityScriptingInterface, &EntityScriptingInterface::enterEntity);
     connect(this, &EntityTreeRenderer::leaveEntity, entityScriptingInterface, &EntityScriptingInterface::leaveEntity);
diff --git a/libraries/entities/src/HoverOverlayInterface.cpp b/libraries/entities/src/HoverOverlayInterface.cpp
new file mode 100644
index 0000000000..85b2738fc4
--- /dev/null
+++ b/libraries/entities/src/HoverOverlayInterface.cpp
@@ -0,0 +1,30 @@
+//
+//  HoverOverlayInterface.cpp
+//  libraries/entities/src
+//
+//  Created by Zach Fox on 2017-07-14.
+//  Copyright 2017 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#include "HoverOverlayInterface.h"
+
+HoverOverlayInterface::HoverOverlayInterface() {
+    // "hover_overlay" debug log category disabled by default.
+    // Create your own "qtlogging.ini" file and set your "QT_LOGGING_CONF" environment variable
+    // if you'd like to enable/disable certain categories.
+    // More details: http://doc.qt.io/qt-5/qloggingcategory.html#configuring-categories
+    QLoggingCategory::setFilterRules(QStringLiteral("hifi.hover_overlay.debug=false"));
+}
+
+void HoverOverlayInterface::createHoverOverlay(const EntityItemID& entityItemID, const PointerEvent& event) {
+    qCDebug(hover_overlay) << "Creating Hover Overlay on top of entity with ID: " << entityItemID;
+    setCurrentHoveredEntity(entityItemID);
+}
+
+void HoverOverlayInterface::destroyHoverOverlay(const EntityItemID& entityItemID, const PointerEvent& event) {
+    qCDebug(hover_overlay) << "Destroying Hover Overlay on top of entity with ID: " << entityItemID;
+    setCurrentHoveredEntity(QUuid());
+}
diff --git a/libraries/entities/src/HoverOverlayInterface.h b/libraries/entities/src/HoverOverlayInterface.h
new file mode 100644
index 0000000000..1e56cc03dd
--- /dev/null
+++ b/libraries/entities/src/HoverOverlayInterface.h
@@ -0,0 +1,44 @@
+//
+//  HoverOverlayInterface.h
+//  libraries/entities/src
+//
+//  Created by Zach Fox on 2017-07-14.
+//  Copyright 2017 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#pragma once
+#ifndef hifi_HoverOverlayInterface_h
+#define hifi_HoverOverlayInterface_h
+
+#include <QtCore/QObject>
+#include <QUuid>
+
+#include <DependencyManager.h>
+#include <PointerEvent.h>
+
+#include "EntityTree.h"
+#include "HoverOverlayLogging.h"
+
+class HoverOverlayInterface : public QObject, public Dependency  {
+    Q_OBJECT
+
+    Q_PROPERTY(QUuid currentHoveredEntity READ getCurrentHoveredEntity WRITE setCurrentHoveredEntity)
+public:
+    HoverOverlayInterface();
+
+    Q_INVOKABLE QUuid getCurrentHoveredEntity() { return _currentHoveredEntity; }
+    void setCurrentHoveredEntity(const QUuid& entityID) { _currentHoveredEntity = entityID; }
+
+public slots:
+    void createHoverOverlay(const EntityItemID& entityItemID, const PointerEvent& event);
+    void destroyHoverOverlay(const EntityItemID& entityItemID, const PointerEvent& event);
+
+private:
+    bool _verboseLogging { true };
+    QUuid _currentHoveredEntity{};
+};
+
+#endif // hifi_HoverOverlayInterface_h
diff --git a/libraries/entities/src/HoverOverlayLogging.cpp b/libraries/entities/src/HoverOverlayLogging.cpp
new file mode 100644
index 0000000000..99a2dff782
--- /dev/null
+++ b/libraries/entities/src/HoverOverlayLogging.cpp
@@ -0,0 +1,14 @@
+//
+//  HoverOverlayLogging.cpp
+//  libraries/entities/src
+//
+//  Created by Zach Fox on 2017-07-17
+//  Copyright 2017 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#include "HoverOverlayLogging.h"
+
+Q_LOGGING_CATEGORY(hover_overlay, "hifi.hover_overlay")
diff --git a/libraries/entities/src/HoverOverlayLogging.h b/libraries/entities/src/HoverOverlayLogging.h
new file mode 100644
index 0000000000..f0a024bba9
--- /dev/null
+++ b/libraries/entities/src/HoverOverlayLogging.h
@@ -0,0 +1,20 @@
+//
+//  HoverOverlayLogging.h
+//  libraries/entities/src
+//
+//  Created by Zach Fox on 2017-07-17
+//  Copyright 2017 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#pragma once
+#ifndef hifi_HoverOverlayLogging_h
+#define hifi_HoverOverlayLogging_h
+
+#include <QLoggingCategory>
+
+Q_DECLARE_LOGGING_CATEGORY(hover_overlay)
+
+#endif // hifi_HoverOverlayLogging_h
diff --git a/libraries/ui/src/ui/OffscreenQmlSurface.cpp b/libraries/ui/src/ui/OffscreenQmlSurface.cpp
index 9df727424f..34865ea058 100644
--- a/libraries/ui/src/ui/OffscreenQmlSurface.cpp
+++ b/libraries/ui/src/ui/OffscreenQmlSurface.cpp
@@ -264,9 +264,6 @@ QNetworkAccessManager* QmlNetworkAccessManagerFactory::create(QObject* parent) {
     return new QmlNetworkAccessManager(parent);
 }
 
-static QQmlEngine* globalEngine { nullptr };
-static size_t globalEngineRefCount { 0 };
-
 QString getEventBridgeJavascript() {
     // FIXME: Refactor with similar code in RenderableWebEntityItem
     QString javaScriptToInject;
@@ -300,9 +297,44 @@ private:
 };
 
 
+#define SINGLE_QML_ENGINE 0
+
+#if SINGLE_QML_ENGINE
+static QQmlEngine* globalEngine{ nullptr };
+static size_t globalEngineRefCount{ 0 };
+#endif
+
+void initializeQmlEngine(QQmlEngine* engine, QQuickWindow* window) {
+    engine->setNetworkAccessManagerFactory(new QmlNetworkAccessManagerFactory);
+    auto importList = engine->importPathList();
+    importList.insert(importList.begin(), PathUtils::resourcesPath());
+    engine->setImportPathList(importList);
+    for (const auto& path : importList) {
+        qDebug() << path;
+    }
+
+    if (!engine->incubationController()) {
+        engine->setIncubationController(window->incubationController());
+    }
+    auto rootContext = engine->rootContext();
+    rootContext->setContextProperty("GL", ::getGLContextData());
+    rootContext->setContextProperty("urlHandler", new UrlHandler());
+    rootContext->setContextProperty("resourceDirectoryUrl", QUrl::fromLocalFile(PathUtils::resourcesPath()));
+    rootContext->setContextProperty("pathToFonts", "../../");
+    rootContext->setContextProperty("ApplicationInterface", qApp);
+    auto javaScriptToInject = getEventBridgeJavascript();
+    if (!javaScriptToInject.isEmpty()) {
+        rootContext->setContextProperty("eventBridgeJavaScriptToInject", QVariant(javaScriptToInject));
+    }
+    rootContext->setContextProperty("FileTypeProfile", new FileTypeProfile(rootContext));
+    rootContext->setContextProperty("HFWebEngineProfile", new HFWebEngineProfile(rootContext));
+    rootContext->setContextProperty("HFTabletWebEngineProfile", new HFTabletWebEngineProfile(rootContext));
+}
 
 QQmlEngine* acquireEngine(QQuickWindow* window) {
     Q_ASSERT(QThread::currentThread() == qApp->thread());
+
+    QQmlEngine* result = nullptr;
     if (QThread::currentThread() != qApp->thread()) {
         qCWarning(uiLogging) << "Cannot acquire QML engine on any thread but the main thread";
     }
@@ -311,47 +343,34 @@ QQmlEngine* acquireEngine(QQuickWindow* window) {
         qmlRegisterType<SoundEffect>("Hifi", 1, 0, "SoundEffect");
     });
 
+
+#if SINGLE_QML_ENGINE
     if (!globalEngine) {
         Q_ASSERT(0 == globalEngineRefCount);
         globalEngine = new QQmlEngine();
-        globalEngine->setNetworkAccessManagerFactory(new QmlNetworkAccessManagerFactory);
-
-        auto importList = globalEngine->importPathList();
-        importList.insert(importList.begin(), PathUtils::resourcesPath());
-        globalEngine->setImportPathList(importList);
-        for (const auto& path : importList) {
-            qDebug() << path;
-        }
-
-        if (!globalEngine->incubationController()) {
-            globalEngine->setIncubationController(window->incubationController());
-        }
-        auto rootContext = globalEngine->rootContext();
-        rootContext->setContextProperty("GL", ::getGLContextData());
-        rootContext->setContextProperty("urlHandler", new UrlHandler());
-        rootContext->setContextProperty("resourceDirectoryUrl", QUrl::fromLocalFile(PathUtils::resourcesPath()));
-        rootContext->setContextProperty("pathToFonts", "../../");
-        rootContext->setContextProperty("ApplicationInterface", qApp);
-        auto javaScriptToInject = getEventBridgeJavascript();
-        if (!javaScriptToInject.isEmpty()) {
-            rootContext->setContextProperty("eventBridgeJavaScriptToInject", QVariant(javaScriptToInject));
-        }
-        rootContext->setContextProperty("FileTypeProfile", new FileTypeProfile(rootContext));
-        rootContext->setContextProperty("HFWebEngineProfile", new HFWebEngineProfile(rootContext));
-        rootContext->setContextProperty("HFTabletWebEngineProfile", new HFTabletWebEngineProfile(rootContext));
+        initializeQmlEngine(result, window);
+        ++globalEngineRefCount;
     }
+    result = globalEngine;
+#else
+    result = new QQmlEngine();
+    initializeQmlEngine(result, window);
+#endif
 
-    ++globalEngineRefCount;
-    return globalEngine;
+    return result;
 }
 
-void releaseEngine() {
+void releaseEngine(QQmlEngine* engine) {
     Q_ASSERT(QThread::currentThread() == qApp->thread());
+#if SINGLE_QML_ENGINE
     Q_ASSERT(0 != globalEngineRefCount);
     if (0 == --globalEngineRefCount) {
         globalEngine->deleteLater();
         globalEngine = nullptr;
     }
+#else
+    engine->deleteLater();
+#endif
 }
 
 void OffscreenQmlSurface::cleanup() {
@@ -456,11 +475,11 @@ OffscreenQmlSurface::~OffscreenQmlSurface() {
     QObject::disconnect(qApp);
 
     cleanup();
-
+    auto engine = _qmlContext->engine();
     _canvas->deleteLater();
     _rootItem->deleteLater();
     _quickWindow->deleteLater();
-    releaseEngine();
+    releaseEngine(engine);
 }
 
 void OffscreenQmlSurface::onAboutToQuit() {
diff --git a/libraries/ui/src/ui/TabletScriptingInterface.cpp b/libraries/ui/src/ui/TabletScriptingInterface.cpp
index 857cae15cc..76f290f17e 100644
--- a/libraries/ui/src/ui/TabletScriptingInterface.cpp
+++ b/libraries/ui/src/ui/TabletScriptingInterface.cpp
@@ -227,7 +227,6 @@ void TabletProxy::setToolbarMode(bool toolbarMode) {
         // forward qml surface events to interface js
         connect(tabletRootWindow, &QmlWindowClass::fromQml, this, &TabletProxy::fromQml);
     } else {
-        _state = State::Home;
         removeButtonsFromToolbar();
         addButtonsToHomeScreen();
         emit screenChanged(QVariant("Home"), QVariant(TABLET_SOURCE_URL));