diff --git a/interface/src/avatar/ModelReferential.cpp b/interface/src/avatar/ModelReferential.cpp
index 85533603f2..8f1360a705 100644
--- a/interface/src/avatar/ModelReferential.cpp
+++ b/interface/src/avatar/ModelReferential.cpp
@@ -69,12 +69,12 @@ void ModelReferential::update() {
     }
 }
 
-int ModelReferential::packExtraData(unsigned char* destinationBuffer) {
+int ModelReferential::packExtraData(unsigned char* destinationBuffer) const {
     memcpy(destinationBuffer, &_modelID, sizeof(_modelID));
     return sizeof(_modelID);
 }
 
-int ModelReferential::unpackExtraData(const unsigned char *sourceBuffer) {
+int ModelReferential::unpackExtraData(const unsigned char *sourceBuffer, int size) {
     memcpy(&_modelID, sourceBuffer, sizeof(_modelID));
     return sizeof(_modelID);
 }
diff --git a/interface/src/avatar/ModelReferential.h b/interface/src/avatar/ModelReferential.h
index e87a09594d..806e4edfcb 100644
--- a/interface/src/avatar/ModelReferential.h
+++ b/interface/src/avatar/ModelReferential.h
@@ -24,8 +24,8 @@ public:
     virtual void update();
     
 protected:
-    virtual int packExtraData(unsigned char* destinationBuffer);
-    virtual int unpackExtraData(const unsigned char* sourceBuffer);
+    virtual int packExtraData(unsigned char* destinationBuffer) const;
+    virtual int unpackExtraData(const unsigned char* sourceBuffer, int size);
     
     uint32_t _modelID;
     ModelTree* _tree;
diff --git a/libraries/avatars/src/Referential.cpp b/libraries/avatars/src/Referential.cpp
index 91c3050e2f..12a0f59186 100644
--- a/libraries/avatars/src/Referential.cpp
+++ b/libraries/avatars/src/Referential.cpp
@@ -36,7 +36,7 @@ Referential::Referential(const unsigned char*& sourceBuffer, AvatarData* avatar)
 Referential::~Referential() {
 }
 
-int Referential::packReferential(unsigned char* destinationBuffer) {
+int Referential::packReferential(unsigned char* destinationBuffer) const {
     const unsigned char* startPosition = destinationBuffer;
     destinationBuffer += pack(destinationBuffer);
     
@@ -53,17 +53,21 @@ int Referential::unpackReferential(const unsigned char* sourceBuffer) {
     sourceBuffer += unpack(sourceBuffer);
     
     char expectedSize = *sourceBuffer++;
-    char bytesRead = unpackExtraData(sourceBuffer);
+    char bytesRead = unpackExtraData(sourceBuffer, expectedSize);
     _isValid = (bytesRead == expectedSize);
+    if (!_isValid) {
+        qDebug() << "[ERROR] Referential extra data overflow";
+    }
     sourceBuffer += expectedSize;
     
     return sourceBuffer - startPosition;
 }
 
-int Referential::pack(unsigned char* destinationBuffer) {
+int Referential::pack(unsigned char* destinationBuffer) const {
     unsigned char* startPosition = destinationBuffer;
     *destinationBuffer++ = (unsigned char)_type;
     memcpy(destinationBuffer, &_createdAt, sizeof(_createdAt));
+    destinationBuffer += sizeof(_createdAt);
     
     destinationBuffer += packFloatVec3ToSignedTwoByteFixed(destinationBuffer, _translation, 0);
     destinationBuffer += packOrientationQuatToBytes(destinationBuffer, _rotation);
@@ -83,13 +87,14 @@ int Referential::unpack(const unsigned char* sourceBuffer) {
     return sourceBuffer - startPosition;
 }
 
-
-int Referential::unpackExtraData(const unsigned char* sourceBuffer) {
-    const unsigned char* startPosition = sourceBuffer;
-    int size = *sourceBuffer;
-    _extraDataBuffer.clear();
-    _extraDataBuffer.setRawData(reinterpret_cast<const char*>(sourceBuffer), size + 1);
-    sourceBuffer += size + 1;
-    return sourceBuffer - startPosition;
+int Referential::packExtraData(unsigned char *destinationBuffer) const {
+    memcpy(destinationBuffer, _extraDataBuffer.data(), _extraDataBuffer.size());
+    return _extraDataBuffer.size();
+}
+
+int Referential::unpackExtraData(const unsigned char* sourceBuffer, int size) {
+    _extraDataBuffer.clear();
+    _extraDataBuffer.setRawData(reinterpret_cast<const char*>(sourceBuffer), size);
+    return size;
 }
 
diff --git a/libraries/avatars/src/Referential.h b/libraries/avatars/src/Referential.h
index b7e3a248e8..713b6a028f 100644
--- a/libraries/avatars/src/Referential.h
+++ b/libraries/avatars/src/Referential.h
@@ -28,24 +28,24 @@ public:
     Referential(const unsigned char*& sourceBuffer, AvatarData* avatar);
     virtual ~Referential();
     
-    Type type() { return _type; }
-    quint64 createdAt() { return _createdAt; }
-    bool isValid() { return _isValid; }
-    bool hasExtraData() { return !_extraDataBuffer.isEmpty(); }
+    Type type() const { return _type; }
+    quint64 createdAt() const { return _createdAt; }
+    bool isValid() const { return _isValid; }
+    bool hasExtraData() const { return !_extraDataBuffer.isEmpty(); }
     
     virtual void update() {}
-    int packReferential(unsigned char* destinationBuffer);
+    int packReferential(unsigned char* destinationBuffer) const;
     int unpackReferential(const unsigned char* sourceBuffer);
     
 protected:
     Referential(Type type, AvatarData* avatar);
     
     // packs the base class data
-    int pack(unsigned char* destinationBuffer);
+    int pack(unsigned char* destinationBuffer) const;
     int unpack(const unsigned char* sourceBuffer);
     // virtual functions that pack fthe extra data of subclasses (needs to be reimplemented in subclass)
-    virtual int packExtraData(unsigned char* destinationBuffer) { return 0; }
-    virtual int unpackExtraData(const unsigned char* sourceBuffer);
+    virtual int packExtraData(unsigned char* destinationBuffer) const;
+    virtual int unpackExtraData(const unsigned char* sourceBuffer, int size);
     
     Type _type;
     quint64 _createdAt;