diff --git a/assignment-client/src/Agent.cpp b/assignment-client/src/Agent.cpp
index dc6b2427f2..e79085244f 100644
--- a/assignment-client/src/Agent.cpp
+++ b/assignment-client/src/Agent.cpp
@@ -499,7 +499,8 @@ void Agent::processAgentAvatar() {
     if (!_scriptEngine->isFinished() && _isAvatar) {
         auto scriptedAvatar = DependencyManager::get<ScriptableAvatar>();
 
-        QByteArray avatarByteArray = scriptedAvatar->toByteArray(true, randFloat() < AVATAR_SEND_FULL_UPDATE_RATIO);
+        QByteArray avatarByteArray = scriptedAvatar->toByteArray((randFloat() < AVATAR_SEND_FULL_UPDATE_RATIO) 
+                                                                    ? AvatarData::SendAllData : AvatarData::CullSmallData);
         scriptedAvatar->doneEncoding(true);
 
         static AvatarDataSequenceNumber sequenceNumber = 0;
diff --git a/assignment-client/src/avatars/AvatarMixer.cpp b/assignment-client/src/avatars/AvatarMixer.cpp
index 70950dc8fc..d8d0b10fea 100644
--- a/assignment-client/src/avatars/AvatarMixer.cpp
+++ b/assignment-client/src/avatars/AvatarMixer.cpp
@@ -44,6 +44,7 @@ AvatarMixer::AvatarMixer(ReceivedMessage& message) :
     connect(DependencyManager::get<NodeList>().data(), &NodeList::nodeKilled, this, &AvatarMixer::nodeKilled);
 
     auto& packetReceiver = DependencyManager::get<NodeList>()->getPacketReceiver();
+    packetReceiver.registerListener(PacketType::ViewFrustum, this, "handleViewFrustumPacket");
     packetReceiver.registerListener(PacketType::AvatarData, this, "handleAvatarDataPacket");
     packetReceiver.registerListener(PacketType::AvatarIdentity, this, "handleAvatarIdentityPacket");
     packetReceiver.registerListener(PacketType::KillAvatar, this, "handleKillAvatarPacket");
@@ -85,6 +86,8 @@ void AvatarMixer::sendIdentityPacket(AvatarMixerClientData* nodeData, const Shar
 //    1) use the view frustum to cull those avatars that are out of view. Since avatar data doesn't need to be present
 //       if the avatar is not in view or in the keyhole.
 void AvatarMixer::broadcastAvatarData() {
+    _broadcastRate.increment();
+
     int idleTime = AVATAR_DATA_SEND_INTERVAL_MSECS;
 
     if (_lastFrameTimestamp.time_since_epoch().count() > 0) {
@@ -173,6 +176,7 @@ void AvatarMixer::broadcastAvatarData() {
                 return;
             }
             ++_sumListeners;
+            nodeData->resetInViewStats();
 
             AvatarData& avatar = nodeData->getAvatar();
             glm::vec3 myPosition = avatar.getClientGlobalPosition();
@@ -379,9 +383,22 @@ void AvatarMixer::broadcastAvatarData() {
                     // start a new segment in the PacketList for this avatar
                     avatarPacketList->startSegment();
 
+                    // determine if avatar is in view, to determine how much data to include...
+                    glm::vec3 otherNodeBoxScale = (otherNodeData->getPosition() - otherNodeData->getGlobalBoundingBoxCorner()) * 2.0f;
+                    AABox otherNodeBox(otherNodeData->getGlobalBoundingBoxCorner(), otherNodeBoxScale);
+
+                    AvatarData::AvatarDataDetail detail;
+                    if (!nodeData->otherAvatarInView(otherNodeBox)) {
+                        detail = AvatarData::MinimumData;
+                        nodeData->incrementAvatarOutOfView();
+                    } else {
+                        detail = distribution(generator) < AVATAR_SEND_FULL_UPDATE_RATIO
+                                        ? AvatarData::SendAllData : AvatarData::IncludeSmallData;
+                        nodeData->incrementAvatarInView();
+                    }
+
                     numAvatarDataBytes += avatarPacketList->write(otherNode->getUUID().toRfc4122());
-                    numAvatarDataBytes +=
-                        avatarPacketList->write(otherAvatar.toByteArray(false, distribution(generator) < AVATAR_SEND_FULL_UPDATE_RATIO));
+                    numAvatarDataBytes += avatarPacketList->write(otherAvatar.toByteArray(detail));
 
                     avatarPacketList->endSegment();
             });
@@ -410,6 +427,9 @@ void AvatarMixer::broadcastAvatarData() {
 
     // We're done encoding this version of the otherAvatars.  Update their "lastSent" joint-states so
     // that we can notice differences, next time around.
+    //
+    // FIXME - this seems suspicious, the code seems to consider all avatars, but not all avatars will
+    // have had their joints sent, so actually we should consider the time since they actually were sent????
     nodeList->eachMatchingNode(
         [&](const SharedNodePointer& otherNode)->bool {
             if (!otherNode->getLinkedData()) {
@@ -434,6 +454,18 @@ void AvatarMixer::broadcastAvatarData() {
         });
 
     _lastFrameTimestamp = p_high_resolution_clock::now();
+
+#ifdef WANT_DEBUG
+    auto sinceLastDebug = p_high_resolution_clock::now() - _lastDebugMessage;
+    auto sinceLastDebugUsecs = std::chrono::duration_cast<std::chrono::microseconds>(sinceLastDebug).count();
+    quint64 DEBUG_INTERVAL = USECS_PER_SECOND * 5;
+
+    if (sinceLastDebugUsecs > DEBUG_INTERVAL) {
+        qDebug() << "broadcast rate:" << _broadcastRate.rate() << "hz";
+        _lastDebugMessage = p_high_resolution_clock::now();
+    }
+#endif
+
 }
 
 void AvatarMixer::nodeKilled(SharedNodePointer killedNode) {
@@ -483,6 +515,18 @@ void AvatarMixer::nodeKilled(SharedNodePointer killedNode) {
     }
 }
 
+void AvatarMixer::handleViewFrustumPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode) {
+    auto nodeList = DependencyManager::get<NodeList>();
+    nodeList->getOrCreateLinkedData(senderNode);
+
+    if (senderNode->getLinkedData()) {
+        AvatarMixerClientData* nodeData = dynamic_cast<AvatarMixerClientData*>(senderNode->getLinkedData());
+        if (nodeData != nullptr) {
+            nodeData->readViewFrustumPacket(message->getMessage());
+        }
+    }
+}
+
 void AvatarMixer::handleAvatarDataPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode) {
     auto nodeList = DependencyManager::get<NodeList>();
     nodeList->updateNodeWithDataFromPacket(message, senderNode);
@@ -529,6 +573,7 @@ void AvatarMixer::sendStatsPacket() {
 
     statsObject["trailing_sleep_percentage"] = _trailingSleepRatio * 100;
     statsObject["performance_throttling_ratio"] = _performanceThrottlingRatio;
+    statsObject["broadcast_loop_rate"] = _broadcastRate.rate();
 
     QJsonObject avatarsObject;
 
@@ -581,6 +626,7 @@ void AvatarMixer::run() {
 
     // setup the timer that will be fired on the broadcast thread
     _broadcastTimer = new QTimer;
+    _broadcastTimer->setTimerType(Qt::PreciseTimer);
     _broadcastTimer->setInterval(AVATAR_DATA_SEND_INTERVAL_MSECS);
     _broadcastTimer->moveToThread(&_broadcastThread);
 
diff --git a/assignment-client/src/avatars/AvatarMixer.h b/assignment-client/src/avatars/AvatarMixer.h
index 3c39380b3a..521fe72f39 100644
--- a/assignment-client/src/avatars/AvatarMixer.h
+++ b/assignment-client/src/avatars/AvatarMixer.h
@@ -15,6 +15,7 @@
 #ifndef hifi_AvatarMixer_h
 #define hifi_AvatarMixer_h
 
+#include <shared/RateCounter.h>
 #include <PortableHighResolutionClock.h>
 
 #include <ThreadedAssignment.h>
@@ -35,6 +36,7 @@ public slots:
     void sendStatsPacket() override;
 
 private slots:
+    void handleViewFrustumPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode);
     void handleAvatarDataPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode);
     void handleAvatarIdentityPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode);
     void handleKillAvatarPacket(QSharedPointer<ReceivedMessage> message);
@@ -67,6 +69,8 @@ private:
 
     QTimer* _broadcastTimer = nullptr;
 
+    RateCounter<> _broadcastRate;
+    p_high_resolution_clock::time_point _lastDebugMessage;
     QHash<QString, QPair<int, int>> _sessionDisplayNames;
 };
 
diff --git a/assignment-client/src/avatars/AvatarMixerClientData.cpp b/assignment-client/src/avatars/AvatarMixerClientData.cpp
index de843c7cea..c65703b8e6 100644
--- a/assignment-client/src/avatars/AvatarMixerClientData.cpp
+++ b/assignment-client/src/avatars/AvatarMixerClientData.cpp
@@ -57,6 +57,14 @@ void AvatarMixerClientData::ignoreOther(SharedNodePointer self, SharedNodePointe
     }
 }
 
+void AvatarMixerClientData::readViewFrustumPacket(const QByteArray& message) {
+    _currentViewFrustum.fromByteArray(message);
+}
+
+bool AvatarMixerClientData::otherAvatarInView(const AABox& otherAvatarBox) {
+    return _currentViewFrustum.boxIntersectsKeyhole(otherAvatarBox);
+}
+
 void AvatarMixerClientData::loadJSONStats(QJsonObject& jsonObject) const {
     jsonObject["display_name"] = _avatar->getDisplayName();
     jsonObject["full_rate_distance"] = _fullRateDistance;
@@ -70,4 +78,6 @@ void AvatarMixerClientData::loadJSONStats(QJsonObject& jsonObject) const {
     jsonObject[INBOUND_AVATAR_DATA_STATS_KEY] = _avatar->getAverageBytesReceivedPerSecond() / (float) BYTES_PER_KILOBIT;
 
     jsonObject["av_data_receive_rate"] = _avatar->getReceiveRate();
+    jsonObject["recent_other_av_in_view"] = _recentOtherAvatarsInView;
+    jsonObject["recent_other_av_out_of_view"] = _recentOtherAvatarsOutOfView;
 }
diff --git a/assignment-client/src/avatars/AvatarMixerClientData.h b/assignment-client/src/avatars/AvatarMixerClientData.h
index 16e886815f..78a30d8206 100644
--- a/assignment-client/src/avatars/AvatarMixerClientData.h
+++ b/assignment-client/src/avatars/AvatarMixerClientData.h
@@ -27,6 +27,7 @@
 #include <PortableHighResolutionClock.h>
 #include <SimpleMovingAverage.h>
 #include <UUIDHasher.h>
+#include <ViewFrustum.h>
 
 const QString OUTBOUND_AVATAR_DATA_STATS_KEY = "outbound_av_data_kbps";
 const QString INBOUND_AVATAR_DATA_STATS_KEY = "inbound_av_data_kbps";
@@ -34,7 +35,7 @@ const QString INBOUND_AVATAR_DATA_STATS_KEY = "inbound_av_data_kbps";
 class AvatarMixerClientData : public NodeData {
     Q_OBJECT
 public:
-    AvatarMixerClientData(const QUuid& nodeID = QUuid()) : NodeData(nodeID) {}
+    AvatarMixerClientData(const QUuid& nodeID = QUuid()) : NodeData(nodeID) { _currentViewFrustum.invalidate(); }
     virtual ~AvatarMixerClientData() {}
     using HRCTime = p_high_resolution_clock::time_point;
 
@@ -91,6 +92,13 @@ public:
     void removeFromRadiusIgnoringSet(const QUuid& other) { _radiusIgnoredOthers.erase(other); }
     void ignoreOther(SharedNodePointer self, SharedNodePointer other);
 
+    void readViewFrustumPacket(const QByteArray& message);
+
+    bool otherAvatarInView(const AABox& otherAvatarBox);
+
+    void resetInViewStats() { _recentOtherAvatarsInView = _recentOtherAvatarsOutOfView = 0; }
+    void incrementAvatarInView() { _recentOtherAvatarsInView++; }
+    void incrementAvatarOutOfView() { _recentOtherAvatarsOutOfView++; }
     const QString& getBaseDisplayName() { return _baseDisplayName; }
     void setBaseDisplayName(const QString& baseDisplayName) { _baseDisplayName = baseDisplayName; }
 
@@ -116,7 +124,10 @@ private:
 
     SimpleMovingAverage _avgOtherAvatarDataRate;
     std::unordered_set<QUuid> _radiusIgnoredOthers;
+    ViewFrustum _currentViewFrustum;
 
+    int _recentOtherAvatarsInView { 0 };
+    int _recentOtherAvatarsOutOfView { 0 };
     QString _baseDisplayName{}; // The santized key used in determinging unique sessionDisplayName, so that we can remove from dictionary.
 };
 
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 27eb66e4f9..b4b0ad10bb 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -4357,6 +4357,7 @@ void Application::update(float deltaTime) {
             if (DependencyManager::get<SceneScriptingInterface>()->shouldRenderEntities()) {
                 queryOctree(NodeType::EntityServer, PacketType::EntityQuery, _entityServerJurisdictions);
             }
+            sendAvatarViewFrustum();
             _lastQueriedViewFrustum = _viewFrustum;
         }
     }
@@ -4396,6 +4397,14 @@ void Application::update(float deltaTime) {
     AnimDebugDraw::getInstance().update();
 }
 
+void Application::sendAvatarViewFrustum() {
+    QByteArray viewFrustumByteArray = _viewFrustum.toByteArray();
+    auto avatarPacket = NLPacket::create(PacketType::ViewFrustum, viewFrustumByteArray.size());
+    avatarPacket->write(viewFrustumByteArray);
+
+    DependencyManager::get<NodeList>()->broadcastToNodes(std::move(avatarPacket), NodeSet() << NodeType::AvatarMixer);
+}
+
 
 int Application::sendNackPackets() {
 
diff --git a/interface/src/Application.h b/interface/src/Application.h
index 23d274aff3..49e30b13d1 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -444,6 +444,7 @@ private:
     void renderRearViewMirror(RenderArgs* renderArgs, const QRect& region, bool isZoomed);
 
     int sendNackPackets();
+    void sendAvatarViewFrustum();
 
     std::shared_ptr<MyAvatar> getMyAvatar() const;
 
diff --git a/interface/src/avatar/MyAvatar.cpp b/interface/src/avatar/MyAvatar.cpp
index 5a31fdbbed..eebcee8e4c 100644
--- a/interface/src/avatar/MyAvatar.cpp
+++ b/interface/src/avatar/MyAvatar.cpp
@@ -226,7 +226,7 @@ void MyAvatar::simulateAttachments(float deltaTime) {
     // don't update attachments here, do it in harvestResultsFromPhysicsSimulation()
 }
 
-QByteArray MyAvatar::toByteArray(bool cullSmallChanges, bool sendAll) {
+QByteArray MyAvatar::toByteArray(AvatarDataDetail dataDetail) {
     CameraMode mode = qApp->getCamera()->getMode();
     _globalPosition = getPosition();
     _globalBoundingBoxCorner.x = _characterController.getCapsuleRadius();
@@ -237,12 +237,12 @@ QByteArray MyAvatar::toByteArray(bool cullSmallChanges, bool sendAll) {
         // fake the avatar position that is sent up to the AvatarMixer
         glm::vec3 oldPosition = getPosition();
         setPosition(getSkeletonPosition());
-        QByteArray array = AvatarData::toByteArray(cullSmallChanges, sendAll);
+        QByteArray array = AvatarData::toByteArray(dataDetail);
         // copy the correct position back
         setPosition(oldPosition);
         return array;
     }
-    return AvatarData::toByteArray(cullSmallChanges, sendAll);
+    return AvatarData::toByteArray(dataDetail);
 }
 
 void MyAvatar::centerBody() {
diff --git a/interface/src/avatar/MyAvatar.h b/interface/src/avatar/MyAvatar.h
index f081ec533b..0e5ce0fe7b 100644
--- a/interface/src/avatar/MyAvatar.h
+++ b/interface/src/avatar/MyAvatar.h
@@ -333,7 +333,7 @@ private:
 
     glm::vec3 getWorldBodyPosition() const;
     glm::quat getWorldBodyOrientation() const;
-    QByteArray toByteArray(bool cullSmallChanges, bool sendAll) override;
+    QByteArray toByteArray(AvatarDataDetail dataDetail) override;
     void simulate(float deltaTime);
     void updateFromTrackers(float deltaTime);
     virtual void render(RenderArgs* renderArgs, const glm::vec3& cameraPositio) override;
diff --git a/libraries/avatars/src/AvatarData.cpp b/libraries/avatars/src/AvatarData.cpp
index 8fdbda70e7..d77f70fbe9 100644
--- a/libraries/avatars/src/AvatarData.cpp
+++ b/libraries/avatars/src/AvatarData.cpp
@@ -181,7 +181,11 @@ void AvatarData::setHandPosition(const glm::vec3& handPosition) {
     _handPosition = glm::inverse(getOrientation()) * (handPosition - getPosition());
 }
 
-QByteArray AvatarData::toByteArray(bool cullSmallChanges, bool sendAll) {
+
+QByteArray AvatarData::toByteArray(AvatarDataDetail dataDetail) {
+    bool cullSmallChanges = (dataDetail == CullSmallData);
+    bool sendAll = (dataDetail == SendAllData);
+    bool sendMinimum = (dataDetail == MinimumData);
     // TODO: DRY this up to a shared method
     // that can pack any type given the number of bytes
     // and return the number of bytes to push the pointer
@@ -199,207 +203,221 @@ QByteArray AvatarData::toByteArray(bool cullSmallChanges, bool sendAll) {
     unsigned char* destinationBuffer = reinterpret_cast<unsigned char*>(avatarDataByteArray.data());
     unsigned char* startPosition = destinationBuffer;
 
-    auto header = reinterpret_cast<AvatarDataPacket::Header*>(destinationBuffer);
-    header->position[0] = getLocalPosition().x;
-    header->position[1] = getLocalPosition().y;
-    header->position[2] = getLocalPosition().z;
-    header->globalPosition[0] = _globalPosition.x;
-    header->globalPosition[1] = _globalPosition.y;
-    header->globalPosition[2] = _globalPosition.z;
-    header->globalBoundingBoxCorner[0] = getPosition().x - _globalBoundingBoxCorner.x;
-    header->globalBoundingBoxCorner[1] = getPosition().y - _globalBoundingBoxCorner.y;
-    header->globalBoundingBoxCorner[2] = getPosition().z - _globalBoundingBoxCorner.z;
-
-    glm::vec3 bodyEulerAngles = glm::degrees(safeEulerAngles(getLocalOrientation()));
-    packFloatAngleToTwoByte((uint8_t*)(header->localOrientation + 0), bodyEulerAngles.y);
-    packFloatAngleToTwoByte((uint8_t*)(header->localOrientation + 1), bodyEulerAngles.x);
-    packFloatAngleToTwoByte((uint8_t*)(header->localOrientation + 2), bodyEulerAngles.z);
-    packFloatRatioToTwoByte((uint8_t*)(&header->scale), getDomainLimitedScale());
-    header->lookAtPosition[0] = _headData->_lookAtPosition.x;
-    header->lookAtPosition[1] = _headData->_lookAtPosition.y;
-    header->lookAtPosition[2] = _headData->_lookAtPosition.z;
-    header->audioLoudness = _headData->_audioLoudness;
-
-    glm::mat4 sensorToWorldMatrix = getSensorToWorldMatrix();
-    packOrientationQuatToSixBytes(header->sensorToWorldQuat, glmExtractRotation(sensorToWorldMatrix));
-    glm::vec3 scale = extractScale(sensorToWorldMatrix);
-    packFloatScalarToSignedTwoByteFixed((uint8_t*)&header->sensorToWorldScale, scale.x, SENSOR_TO_WORLD_SCALE_RADIX);
-    header->sensorToWorldTrans[0] = sensorToWorldMatrix[3][0];
-    header->sensorToWorldTrans[1] = sensorToWorldMatrix[3][1];
-    header->sensorToWorldTrans[2] = sensorToWorldMatrix[3][2];
-
-    setSemiNibbleAt(header->flags, KEY_STATE_START_BIT, _keyState);
-    // hand state
-    bool isFingerPointing = _handState & IS_FINGER_POINTING_FLAG;
-    setSemiNibbleAt(header->flags, HAND_STATE_START_BIT, _handState & ~IS_FINGER_POINTING_FLAG);
-    if (isFingerPointing) {
-        setAtBit(header->flags, HAND_STATE_FINGER_POINTING_BIT);
-    }
-    // faceshift state
-    if (_headData->_isFaceTrackerConnected) {
-        setAtBit(header->flags, IS_FACESHIFT_CONNECTED);
-    }
-    // eye tracker state
-    if (_headData->_isEyeTrackerConnected) {
-        setAtBit(header->flags, IS_EYE_TRACKER_CONNECTED);
-    }
-    // referential state
-    QUuid parentID = getParentID();
-    if (!parentID.isNull()) {
-        setAtBit(header->flags, HAS_REFERENTIAL);
-    }
-    destinationBuffer += sizeof(AvatarDataPacket::Header);
-
-    if (!parentID.isNull()) {
-        auto parentInfo = reinterpret_cast<AvatarDataPacket::ParentInfo*>(destinationBuffer);
-        QByteArray referentialAsBytes = parentID.toRfc4122();
-        memcpy(parentInfo->parentUUID, referentialAsBytes.data(), referentialAsBytes.size());
-        parentInfo->parentJointIndex = _parentJointIndex;
-        destinationBuffer += sizeof(AvatarDataPacket::ParentInfo);
+    // Leading flags, to indicate how much data is actually included in the packet...
+    uint8_t packetStateFlags = 0;
+    if (sendMinimum) {
+        setAtBit(packetStateFlags, AVATARDATA_FLAGS_MINIMUM);
     }
 
-    // If it is connected, pack up the data
-    if (_headData->_isFaceTrackerConnected) {
-        auto faceTrackerInfo = reinterpret_cast<AvatarDataPacket::FaceTrackerInfo*>(destinationBuffer);
+    memcpy(destinationBuffer, &packetStateFlags, sizeof(packetStateFlags));
+    destinationBuffer += sizeof(packetStateFlags);
 
-        faceTrackerInfo->leftEyeBlink = _headData->_leftEyeBlink;
-        faceTrackerInfo->rightEyeBlink = _headData->_rightEyeBlink;
-        faceTrackerInfo->averageLoudness = _headData->_averageLoudness;
-        faceTrackerInfo->browAudioLift = _headData->_browAudioLift;
-        faceTrackerInfo->numBlendshapeCoefficients = _headData->_blendshapeCoefficients.size();
-        destinationBuffer += sizeof(AvatarDataPacket::FaceTrackerInfo);
+    if (sendMinimum) {
+        memcpy(destinationBuffer, &_globalPosition, sizeof(_globalPosition));
+        destinationBuffer += sizeof(_globalPosition);
+    } else {
+        auto header = reinterpret_cast<AvatarDataPacket::Header*>(destinationBuffer);
+        header->position[0] = getLocalPosition().x;
+        header->position[1] = getLocalPosition().y;
+        header->position[2] = getLocalPosition().z;
+        header->globalPosition[0] = _globalPosition.x;
+        header->globalPosition[1] = _globalPosition.y;
+        header->globalPosition[2] = _globalPosition.z;
+        header->globalBoundingBoxCorner[0] = getPosition().x - _globalBoundingBoxCorner.x;
+        header->globalBoundingBoxCorner[1] = getPosition().y - _globalBoundingBoxCorner.y;
+        header->globalBoundingBoxCorner[2] = getPosition().z - _globalBoundingBoxCorner.z;
 
-        // followed by a variable number of float coefficients
-        memcpy(destinationBuffer, _headData->_blendshapeCoefficients.data(), _headData->_blendshapeCoefficients.size() * sizeof(float));
-        destinationBuffer += _headData->_blendshapeCoefficients.size() * sizeof(float);
-    }
+        glm::vec3 bodyEulerAngles = glm::degrees(safeEulerAngles(getLocalOrientation()));
+        packFloatAngleToTwoByte((uint8_t*)(header->localOrientation + 0), bodyEulerAngles.y);
+        packFloatAngleToTwoByte((uint8_t*)(header->localOrientation + 1), bodyEulerAngles.x);
+        packFloatAngleToTwoByte((uint8_t*)(header->localOrientation + 2), bodyEulerAngles.z);
+        packFloatRatioToTwoByte((uint8_t*)(&header->scale), getDomainLimitedScale());
+        header->lookAtPosition[0] = _headData->_lookAtPosition.x;
+        header->lookAtPosition[1] = _headData->_lookAtPosition.y;
+        header->lookAtPosition[2] = _headData->_lookAtPosition.z;
+        header->audioLoudness = _headData->_audioLoudness;
 
-    QReadLocker readLock(&_jointDataLock);
+        glm::mat4 sensorToWorldMatrix = getSensorToWorldMatrix();
+        packOrientationQuatToSixBytes(header->sensorToWorldQuat, glmExtractRotation(sensorToWorldMatrix));
+        glm::vec3 scale = extractScale(sensorToWorldMatrix);
+        packFloatScalarToSignedTwoByteFixed((uint8_t*)&header->sensorToWorldScale, scale.x, SENSOR_TO_WORLD_SCALE_RADIX);
+        header->sensorToWorldTrans[0] = sensorToWorldMatrix[3][0];
+        header->sensorToWorldTrans[1] = sensorToWorldMatrix[3][1];
+        header->sensorToWorldTrans[2] = sensorToWorldMatrix[3][2];
 
-    // joint rotation data
-    *destinationBuffer++ = _jointData.size();
-    unsigned char* validityPosition = destinationBuffer;
-    unsigned char validity = 0;
-    int validityBit = 0;
+        setSemiNibbleAt(header->flags, KEY_STATE_START_BIT, _keyState);
+        // hand state
+        bool isFingerPointing = _handState & IS_FINGER_POINTING_FLAG;
+        setSemiNibbleAt(header->flags, HAND_STATE_START_BIT, _handState & ~IS_FINGER_POINTING_FLAG);
+        if (isFingerPointing) {
+            setAtBit(header->flags, HAND_STATE_FINGER_POINTING_BIT);
+        }
+        // faceshift state
+        if (_headData->_isFaceTrackerConnected) {
+            setAtBit(header->flags, IS_FACESHIFT_CONNECTED);
+        }
+        // eye tracker state
+        if (_headData->_isEyeTrackerConnected) {
+            setAtBit(header->flags, IS_EYE_TRACKER_CONNECTED);
+        }
+        // referential state
+        QUuid parentID = getParentID();
+        if (!parentID.isNull()) {
+            setAtBit(header->flags, HAS_REFERENTIAL);
+        }
+        destinationBuffer += sizeof(AvatarDataPacket::Header);
 
-    #ifdef WANT_DEBUG
-    int rotationSentCount = 0;
-    unsigned char* beforeRotations = destinationBuffer;
-    #endif
+        if (!parentID.isNull()) {
+            auto parentInfo = reinterpret_cast<AvatarDataPacket::ParentInfo*>(destinationBuffer);
+            QByteArray referentialAsBytes = parentID.toRfc4122();
+            memcpy(parentInfo->parentUUID, referentialAsBytes.data(), referentialAsBytes.size());
+            parentInfo->parentJointIndex = _parentJointIndex;
+            destinationBuffer += sizeof(AvatarDataPacket::ParentInfo);
+        }
 
-    _lastSentJointData.resize(_jointData.size());
+        // If it is connected, pack up the data
+        if (_headData->_isFaceTrackerConnected) {
+            auto faceTrackerInfo = reinterpret_cast<AvatarDataPacket::FaceTrackerInfo*>(destinationBuffer);
 
-    for (int i=0; i < _jointData.size(); i++) {
-        const JointData& data = _jointData[i];
-        if (sendAll || _lastSentJointData[i].rotation != data.rotation) {
-            if (sendAll ||
-                !cullSmallChanges ||
-                fabsf(glm::dot(data.rotation, _lastSentJointData[i].rotation)) <= AVATAR_MIN_ROTATION_DOT) {
-                if (data.rotationSet) {
-                    validity |= (1 << validityBit);
-                    #ifdef WANT_DEBUG
-                    rotationSentCount++;
-                    #endif
+            faceTrackerInfo->leftEyeBlink = _headData->_leftEyeBlink;
+            faceTrackerInfo->rightEyeBlink = _headData->_rightEyeBlink;
+            faceTrackerInfo->averageLoudness = _headData->_averageLoudness;
+            faceTrackerInfo->browAudioLift = _headData->_browAudioLift;
+            faceTrackerInfo->numBlendshapeCoefficients = _headData->_blendshapeCoefficients.size();
+            destinationBuffer += sizeof(AvatarDataPacket::FaceTrackerInfo);
+
+            // followed by a variable number of float coefficients
+            memcpy(destinationBuffer, _headData->_blendshapeCoefficients.data(), _headData->_blendshapeCoefficients.size() * sizeof(float));
+            destinationBuffer += _headData->_blendshapeCoefficients.size() * sizeof(float);
+        }
+
+        QReadLocker readLock(&_jointDataLock);
+
+        // joint rotation data
+        *destinationBuffer++ = _jointData.size();
+        unsigned char* validityPosition = destinationBuffer;
+        unsigned char validity = 0;
+        int validityBit = 0;
+
+        #ifdef WANT_DEBUG
+        int rotationSentCount = 0;
+        unsigned char* beforeRotations = destinationBuffer;
+        #endif
+
+        _lastSentJointData.resize(_jointData.size());
+
+        for (int i=0; i < _jointData.size(); i++) {
+            const JointData& data = _jointData[i];
+            if (sendAll || _lastSentJointData[i].rotation != data.rotation) {
+                if (sendAll ||
+                    !cullSmallChanges ||
+                    fabsf(glm::dot(data.rotation, _lastSentJointData[i].rotation)) <= AVATAR_MIN_ROTATION_DOT) {
+                    if (data.rotationSet) {
+                        validity |= (1 << validityBit);
+                        #ifdef WANT_DEBUG
+                        rotationSentCount++;
+                        #endif
+                    }
                 }
             }
-        }
-        if (++validityBit == BITS_IN_BYTE) {
-            *destinationBuffer++ = validity;
-            validityBit = validity = 0;
-        }
-    }
-    if (validityBit != 0) {
-        *destinationBuffer++ = validity;
-    }
-
-    validityBit = 0;
-    validity = *validityPosition++;
-    for (int i = 0; i < _jointData.size(); i ++) {
-        const JointData& data = _jointData[i];
-        if (validity & (1 << validityBit)) {
-            destinationBuffer += packOrientationQuatToSixBytes(destinationBuffer, data.rotation);
-        }
-        if (++validityBit == BITS_IN_BYTE) {
-            validityBit = 0;
-            validity = *validityPosition++;
-        }
-    }
-
-
-    // joint translation data
-    validityPosition = destinationBuffer;
-    validity = 0;
-    validityBit = 0;
-
-    #ifdef WANT_DEBUG
-    int translationSentCount = 0;
-    unsigned char* beforeTranslations = destinationBuffer;
-    #endif
-
-    float maxTranslationDimension = 0.0;
-    for (int i=0; i < _jointData.size(); i++) {
-        const JointData& data = _jointData[i];
-        if (sendAll || _lastSentJointData[i].translation != data.translation) {
-            if (sendAll ||
-                !cullSmallChanges ||
-                glm::distance(data.translation, _lastSentJointData[i].translation) > AVATAR_MIN_TRANSLATION) {
-                if (data.translationSet) {
-                    validity |= (1 << validityBit);
-                    #ifdef WANT_DEBUG
-                    translationSentCount++;
-                    #endif
-                    maxTranslationDimension = glm::max(fabsf(data.translation.x), maxTranslationDimension);
-                    maxTranslationDimension = glm::max(fabsf(data.translation.y), maxTranslationDimension);
-                    maxTranslationDimension = glm::max(fabsf(data.translation.z), maxTranslationDimension);
-                }
+            if (++validityBit == BITS_IN_BYTE) {
+                *destinationBuffer++ = validity;
+                validityBit = validity = 0;
             }
         }
-        if (++validityBit == BITS_IN_BYTE) {
+        if (validityBit != 0) {
             *destinationBuffer++ = validity;
-            validityBit = validity = 0;
         }
-    }
 
-    if (validityBit != 0) {
-        *destinationBuffer++ = validity;
-    }
-
-    validityBit = 0;
-    validity = *validityPosition++;
-    for (int i = 0; i < _jointData.size(); i ++) {
-        const JointData& data = _jointData[i];
-        if (validity & (1 << validityBit)) {
-            destinationBuffer +=
-                packFloatVec3ToSignedTwoByteFixed(destinationBuffer, data.translation, TRANSLATION_COMPRESSION_RADIX);
+        validityBit = 0;
+        validity = *validityPosition++;
+        for (int i = 0; i < _jointData.size(); i ++) {
+            const JointData& data = _jointData[i];
+            if (validity & (1 << validityBit)) {
+                destinationBuffer += packOrientationQuatToSixBytes(destinationBuffer, data.rotation);
+            }
+            if (++validityBit == BITS_IN_BYTE) {
+                validityBit = 0;
+                validity = *validityPosition++;
+            }
         }
-        if (++validityBit == BITS_IN_BYTE) {
-            validityBit = 0;
-            validity = *validityPosition++;
+
+
+        // joint translation data
+        validityPosition = destinationBuffer;
+        validity = 0;
+        validityBit = 0;
+
+        #ifdef WANT_DEBUG
+        int translationSentCount = 0;
+        unsigned char* beforeTranslations = destinationBuffer;
+        #endif
+
+        float maxTranslationDimension = 0.0;
+        for (int i=0; i < _jointData.size(); i++) {
+            const JointData& data = _jointData[i];
+            if (sendAll || _lastSentJointData[i].translation != data.translation) {
+                if (sendAll ||
+                    !cullSmallChanges ||
+                    glm::distance(data.translation, _lastSentJointData[i].translation) > AVATAR_MIN_TRANSLATION) {
+                    if (data.translationSet) {
+                        validity |= (1 << validityBit);
+                        #ifdef WANT_DEBUG
+                        translationSentCount++;
+                        #endif
+                        maxTranslationDimension = glm::max(fabsf(data.translation.x), maxTranslationDimension);
+                        maxTranslationDimension = glm::max(fabsf(data.translation.y), maxTranslationDimension);
+                        maxTranslationDimension = glm::max(fabsf(data.translation.z), maxTranslationDimension);
+                    }
+                }
+            }
+            if (++validityBit == BITS_IN_BYTE) {
+                *destinationBuffer++ = validity;
+                validityBit = validity = 0;
+            }
         }
-    }
 
-    // faux joints
-    Transform controllerLeftHandTransform = Transform(getControllerLeftHandMatrix());
-    destinationBuffer += packOrientationQuatToSixBytes(destinationBuffer, controllerLeftHandTransform.getRotation());
-    destinationBuffer += packFloatVec3ToSignedTwoByteFixed(destinationBuffer, controllerLeftHandTransform.getTranslation(),
-                                                           TRANSLATION_COMPRESSION_RADIX);
-    Transform controllerRightHandTransform = Transform(getControllerRightHandMatrix());
-    destinationBuffer += packOrientationQuatToSixBytes(destinationBuffer, controllerRightHandTransform.getRotation());
-    destinationBuffer += packFloatVec3ToSignedTwoByteFixed(destinationBuffer, controllerRightHandTransform.getTranslation(),
-                                                           TRANSLATION_COMPRESSION_RADIX);
+        if (validityBit != 0) {
+            *destinationBuffer++ = validity;
+        }
 
-    #ifdef WANT_DEBUG
-    if (sendAll) {
-        qCDebug(avatars) << "AvatarData::toByteArray" << cullSmallChanges << sendAll
-                 << "rotations:" << rotationSentCount << "translations:" << translationSentCount
-                 << "largest:" << maxTranslationDimension
-                 << "size:"
-                 << (beforeRotations - startPosition) << "+"
-                 << (beforeTranslations - beforeRotations) << "+"
-                 << (destinationBuffer - beforeTranslations) << "="
-                 << (destinationBuffer - startPosition);
+        validityBit = 0;
+        validity = *validityPosition++;
+        for (int i = 0; i < _jointData.size(); i ++) {
+            const JointData& data = _jointData[i];
+            if (validity & (1 << validityBit)) {
+                destinationBuffer +=
+                    packFloatVec3ToSignedTwoByteFixed(destinationBuffer, data.translation, TRANSLATION_COMPRESSION_RADIX);
+            }
+            if (++validityBit == BITS_IN_BYTE) {
+                validityBit = 0;
+                validity = *validityPosition++;
+            }
+        }
+
+        // faux joints
+        Transform controllerLeftHandTransform = Transform(getControllerLeftHandMatrix());
+        destinationBuffer += packOrientationQuatToSixBytes(destinationBuffer, controllerLeftHandTransform.getRotation());
+        destinationBuffer += packFloatVec3ToSignedTwoByteFixed(destinationBuffer, controllerLeftHandTransform.getTranslation(),
+                                                               TRANSLATION_COMPRESSION_RADIX);
+        Transform controllerRightHandTransform = Transform(getControllerRightHandMatrix());
+        destinationBuffer += packOrientationQuatToSixBytes(destinationBuffer, controllerRightHandTransform.getRotation());
+        destinationBuffer += packFloatVec3ToSignedTwoByteFixed(destinationBuffer, controllerRightHandTransform.getTranslation(),
+                                                               TRANSLATION_COMPRESSION_RADIX);
+
+        #ifdef WANT_DEBUG
+        if (sendAll) {
+            qCDebug(avatars) << "AvatarData::toByteArray" << cullSmallChanges << sendAll
+                     << "rotations:" << rotationSentCount << "translations:" << translationSentCount
+                     << "largest:" << maxTranslationDimension
+                     << "size:"
+                     << (beforeRotations - startPosition) << "+"
+                     << (beforeTranslations - beforeRotations) << "+"
+                     << (destinationBuffer - beforeTranslations) << "="
+                     << (destinationBuffer - startPosition);
+        }
+        #endif
     }
-    #endif
 
     return avatarDataByteArray.left(destinationBuffer - startPosition);
 }
@@ -474,9 +492,22 @@ int AvatarData::parseDataFromBuffer(const QByteArray& buffer) {
         _headData = new HeadData(this);
     }
 
+    uint8_t packetStateFlags = buffer.at(0);
+    bool minimumSent = oneAtBit(packetStateFlags, AVATARDATA_FLAGS_MINIMUM);
+
     const unsigned char* startPosition = reinterpret_cast<const unsigned char*>(buffer.data());
     const unsigned char* endPosition = startPosition + buffer.size();
-    const unsigned char* sourceBuffer = startPosition;
+    const unsigned char* sourceBuffer = startPosition + sizeof(packetStateFlags); // skip the flags!!
+
+    // if this is the minimum, then it only includes the flags
+    if (minimumSent) {
+        memcpy(&_globalPosition, sourceBuffer, sizeof(_globalPosition));
+        sourceBuffer += sizeof(_globalPosition);
+        int numBytesRead = (sourceBuffer - startPosition);
+        _averageBytesReceived.updateAverage(numBytesRead);
+        return numBytesRead;
+    }
+
     quint64 now = usecTimestampNow();
 
     PACKET_READ_CHECK(Header, sizeof(AvatarDataPacket::Header));
@@ -1181,9 +1212,9 @@ void AvatarData::sendAvatarDataPacket() {
 
     // about 2% of the time, we send a full update (meaning, we transmit all the joint data), even if nothing has changed.
     // this is to guard against a joint moving once, the packet getting lost, and the joint never moving again.
-    bool sendFullUpdate = randFloat() < AVATAR_SEND_FULL_UPDATE_RATIO;
-    QByteArray avatarByteArray = toByteArray(true, sendFullUpdate);
-    doneEncoding(true);
+    QByteArray avatarByteArray = toByteArray((randFloat() < AVATAR_SEND_FULL_UPDATE_RATIO) ? SendAllData : CullSmallData);
+
+    doneEncoding(true); // FIXME - doneEncoding() takes a bool for culling small changes, that's janky!
 
     static AvatarDataSequenceNumber sequenceNumber = 0;
 
diff --git a/libraries/avatars/src/AvatarData.h b/libraries/avatars/src/AvatarData.h
index 906d9b312a..db06d52092 100644
--- a/libraries/avatars/src/AvatarData.h
+++ b/libraries/avatars/src/AvatarData.h
@@ -106,6 +106,11 @@ const char LEFT_HAND_POINTING_FLAG = 1;
 const char RIGHT_HAND_POINTING_FLAG = 2;
 const char IS_FINGER_POINTING_FLAG = 4;
 
+// AvatarData state flags - we store the details about the packet encoding in the first byte, 
+// before the "header" structure
+const char AVATARDATA_FLAGS_MINIMUM = 0;
+
+
 static const float MAX_AVATAR_SCALE = 1000.0f;
 static const float MIN_AVATAR_SCALE = .005f;
 
@@ -204,7 +209,14 @@ public:
     glm::vec3 getHandPosition() const;
     void setHandPosition(const glm::vec3& handPosition);
 
-    virtual QByteArray toByteArray(bool cullSmallChanges, bool sendAll);
+    typedef enum { 
+        MinimumData, 
+        CullSmallData,
+        IncludeSmallData,
+        SendAllData
+    } AvatarDataDetail;
+
+    virtual QByteArray toByteArray(AvatarDataDetail dataDetail);
     virtual void doneEncoding(bool cullSmallChanges);
 
     /// \return true if an error should be logged
diff --git a/libraries/networking/src/udt/PacketHeaders.h b/libraries/networking/src/udt/PacketHeaders.h
index e2dff2a65d..162e565b83 100644
--- a/libraries/networking/src/udt/PacketHeaders.h
+++ b/libraries/networking/src/udt/PacketHeaders.h
@@ -103,7 +103,8 @@ public:
         RadiusIgnoreRequest,
         UsernameFromIDRequest,
         UsernameFromIDReply,
-        LAST_PACKET_TYPE = UsernameFromIDReply
+        ViewFrustum,
+        LAST_PACKET_TYPE = ViewFrustum
     };
 };
 
diff --git a/libraries/shared/src/ViewFrustum.cpp b/libraries/shared/src/ViewFrustum.cpp
index 0a1a41ace1..b4ed462639 100644
--- a/libraries/shared/src/ViewFrustum.cpp
+++ b/libraries/shared/src/ViewFrustum.cpp
@@ -130,6 +130,75 @@ const char* ViewFrustum::debugPlaneName (int plane) const {
     return "Unknown";
 }
 
+void ViewFrustum::fromByteArray(const QByteArray& input) {
+
+    // From the wire!
+    glm::vec3 cameraPosition;
+    glm::quat cameraOrientation;
+    float cameraCenterRadius;
+    float cameraFov;
+    float cameraAspectRatio;
+    float cameraNearClip;
+    float cameraFarClip;
+
+    const unsigned char* startPosition = reinterpret_cast<const unsigned char*>(input.constData());
+    const unsigned char* sourceBuffer = startPosition;
+
+    // camera details
+    memcpy(&cameraPosition, sourceBuffer, sizeof(cameraPosition));
+    sourceBuffer += sizeof(cameraPosition);
+    sourceBuffer += unpackOrientationQuatFromBytes(sourceBuffer, cameraOrientation);
+    sourceBuffer += unpackFloatAngleFromTwoByte((uint16_t*)sourceBuffer, &cameraFov);
+    sourceBuffer += unpackFloatRatioFromTwoByte(sourceBuffer, cameraAspectRatio);
+    sourceBuffer += unpackClipValueFromTwoByte(sourceBuffer, cameraNearClip);
+    sourceBuffer += unpackClipValueFromTwoByte(sourceBuffer, cameraFarClip);
+    memcpy(&cameraCenterRadius, sourceBuffer, sizeof(cameraCenterRadius));
+    sourceBuffer += sizeof(cameraCenterRadius);
+
+    setPosition(cameraPosition);
+    setOrientation(cameraOrientation);
+    setCenterRadius(cameraCenterRadius);
+
+    // Also make sure it's got the correct lens details from the camera
+    const float VIEW_FRUSTUM_FOV_OVERSEND = 60.0f;
+    float originalFOV = cameraFov;
+    float wideFOV = originalFOV + VIEW_FRUSTUM_FOV_OVERSEND;
+
+    if (0.0f != cameraAspectRatio &&
+        0.0f != cameraNearClip &&
+        0.0f != cameraFarClip &&
+        cameraNearClip != cameraFarClip) {
+        setProjection(glm::perspective(
+            glm::radians(wideFOV), // hack
+            cameraAspectRatio,
+            cameraNearClip,
+            cameraFarClip));
+
+        calculate();
+    }
+}
+
+
+QByteArray ViewFrustum::toByteArray() {
+    static const int LARGE_ENOUGH = 1024;
+    QByteArray viewFrustumDataByteArray(LARGE_ENOUGH, 0);
+    unsigned char* destinationBuffer = reinterpret_cast<unsigned char*>(viewFrustumDataByteArray.data());
+    unsigned char* startPosition = destinationBuffer;
+
+    // camera details
+    memcpy(destinationBuffer, &_position, sizeof(_position));
+    destinationBuffer += sizeof(_position);
+    destinationBuffer += packOrientationQuatToBytes(destinationBuffer, _orientation);
+    destinationBuffer += packFloatAngleToTwoByte(destinationBuffer, _fieldOfView);
+    destinationBuffer += packFloatRatioToTwoByte(destinationBuffer, _aspectRatio);
+    destinationBuffer += packClipValueToTwoByte(destinationBuffer, _nearClip);
+    destinationBuffer += packClipValueToTwoByte(destinationBuffer, _farClip);
+    memcpy(destinationBuffer, &_centerSphereRadius, sizeof(_centerSphereRadius));
+    destinationBuffer += sizeof(_centerSphereRadius);
+
+    return viewFrustumDataByteArray.left(destinationBuffer - startPosition);
+}
+
 ViewFrustum::intersection ViewFrustum::calculateCubeFrustumIntersection(const AACube& cube) const {
     // only check against frustum
     ViewFrustum::intersection result = INSIDE;
diff --git a/libraries/shared/src/ViewFrustum.h b/libraries/shared/src/ViewFrustum.h
index 091aff7a92..9a6cb9ab68 100644
--- a/libraries/shared/src/ViewFrustum.h
+++ b/libraries/shared/src/ViewFrustum.h
@@ -139,6 +139,10 @@ public:
     const ::Plane* getPlanes() const { return _planes; }
 
     void invalidate(); // causes all reasonable intersection tests to fail
+
+    QByteArray toByteArray();
+    void fromByteArray(const QByteArray& input);
+
 private:
     glm::mat4 _view;
     glm::mat4 _projection;