diff --git a/pymvr/__init__.py b/pymvr/__init__.py
index ecf28c9..fe622d6 100644
--- a/pymvr/__init__.py
+++ b/pymvr/__init__.py
@@ -31,7 +31,7 @@
 from .value import Matrix, Color  # type: ignore
 from enum import Enum
 
-__version__ = "1.0.2"
+__version__ = "1.0.3.dev9"
 
 
 def _find_root(pkg: "zipfile.ZipFile") -> "ElementTree.Element":
@@ -91,7 +91,7 @@ def __init__(self):
             verMajor=self.version_major,
             verMinor=self.version_minor,
             provider=self.provider,
-            provider_version=self.provider_version,
+            providerVersion=self.provider_version,
         )
 
     def write_mvr(self, path: Optional[str] = None):
@@ -207,7 +207,7 @@ def __init__(
         *args,
         **kwargs,
     ):
-        self.layers = layers
+        self.layers = layers if layers else Layers()
         self.aux_data = aux_data
         super().__init__(xml_node, *args, **kwargs)
 
@@ -215,6 +215,8 @@ def _read_xml(self, xml_node: "Element"):
         layers_node = xml_node.find("Layers")
         if layers_node is not None:
             self.layers = Layers(xml_node=layers_node)
+        else:
+            self.layers = Layers()
 
         aux_data_collect = xml_node.find("AUXData")
 
@@ -225,11 +227,10 @@ def _read_xml(self, xml_node: "Element"):
 
     def to_xml(self, parent: Element):
         element = ElementTree.SubElement(parent, "Scene")
-        if self.layers:
+        if self.layers is not None:
             self.layers.to_xml(element)
         if self.aux_data:
             self.aux_data.to_xml(element)
-        return element
 
 
 class Layers(BaseNode):
@@ -298,7 +299,6 @@ def to_xml(self, parent: Element):
         element = ElementTree.SubElement(parent, type(self).__name__)
         for _data in self.data:
             element.append(_data.to_xml())
-        return element
 
 
 class ScaleHandelingEnum(Enum):
@@ -412,13 +412,13 @@ def __len__(self):
 class BaseChildNode(BaseNode):
     def __init__(
         self,
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         uuid: Optional[str] = None,
         gdtf_spec: Optional[str] = None,
         gdtf_mode: Optional[str] = None,
         matrix: Optional[Matrix] = None,
         classing: Optional[str] = None,
-        fixture_id: Optional[str] = None,
+        fixture_id: Optional[str] = "",
         fixture_id_numeric: int = 0,
         unit_number: int = 0,
         custom_id: int = 0,
@@ -461,7 +461,7 @@ def __init__(
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name")
+        self.name = xml_node.attrib.get("name") or ""
         uuid = xml_node.attrib.get("uuid")
         if uuid is not None:
             self.uuid = uuid
@@ -487,7 +487,7 @@ def _read_xml(self, xml_node: "Element"):
 
         _fixture_id_node = xml_node.find("FixtureID")
         if _fixture_id_node is not None:
-            self.fixture_id = _fixture_id_node.text
+            self.fixture_id = _fixture_id_node.text or ""
 
         _fixture_id_numeric_node = xml_node.find("FixtureIDNumeric")
         if (
@@ -572,7 +572,9 @@ def populate_xml(self, element: Element):
         if self.connections:
             self.connections.to_xml(element)
 
-        ElementTree.SubElement(element, "FixtureID").text = str(self.fixture_id) or "0"
+        ElementTree.SubElement(element, "FixtureID").text = (
+            str(self.fixture_id or "") or ""
+        )
         ElementTree.SubElement(element, "FixtureIDNumeric").text = str(
             self.fixture_id_numeric
         )
@@ -692,7 +694,7 @@ def to_xml(self, parent: Element):
 class MappingDefinition(BaseNode):
     def __init__(
         self,
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         uuid: Optional[str] = None,
         size_x: int = 0,
         size_y: int = 0,
@@ -703,6 +705,8 @@ def __init__(
         **kwargs,
     ):
         self.name = name
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
         self.uuid = uuid
         self.size_x = size_x
         self.size_y = size_y
@@ -713,8 +717,10 @@ def __init__(
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name")
-        self.uuid = xml_node.attrib.get("uuid")
+        self.name = xml_node.attrib.get("name") or ""
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
 
         size_x_node = xml_node.find("SizeX")
         if size_x_node is not None and size_x_node.text is not None:
@@ -757,7 +763,6 @@ def __init__(
         protocols: Optional["Protocols"] = None,
         mappings: Optional["Mappings"] = None,
         gobo: Optional["Gobo"] = None,
-        unit_number: int = 0,
         xml_node: Optional["Element"] = None,
         *args,
         **kwargs,
@@ -772,7 +777,6 @@ def __init__(
         self.protocols = protocols if protocols is not None else Protocols()
         self.mappings = mappings if mappings is not None else Mappings()
         self.gobo = gobo
-        self.unit_number = unit_number
         kwargs["xml_node"] = xml_node
         super().__init__(*args, **kwargs)
 
@@ -821,10 +825,6 @@ def _read_xml(self, xml_node: "Element"):
         if gobo_node is not None:
             self.gobo = Gobo(xml_node=gobo_node)
 
-        unit_number_node = xml_node.find("UnitNumber")
-        if unit_number_node is not None and unit_number_node.text is not None:
-            self.unit_number = int(unit_number_node.text)
-
     def to_xml(self):
         attributes = {"name": self.name, "uuid": self.uuid}
         if self.multipatch:
@@ -858,8 +858,6 @@ def to_xml(self):
         if self.gobo:
             element.append(self.gobo.to_xml())
 
-        ElementTree.SubElement(element, "UnitNumber").text = str(self.unit_number)
-
         return element
 
     def __str__(self):
@@ -869,7 +867,7 @@ def __str__(self):
 class GroupObject(BaseNode):
     def __init__(
         self,
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         uuid: Optional[str] = None,
         classing: Optional[str] = None,
         child_list: Optional["ChildList"] = None,
@@ -879,7 +877,9 @@ def __init__(
         **kwargs,
     ):
         self.name = name
-        self.uuid = uuid
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
+        self.uuid: str = uuid
         self.classing = classing
         self.child_list = child_list
         self.matrix = matrix if matrix is not None else Matrix(0)
@@ -887,8 +887,10 @@ def __init__(
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name")
-        self.uuid = xml_node.attrib.get("uuid")
+        self.name = xml_node.attrib.get("name") or ""
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
         classing_node = xml_node.find("Classing")
         if classing_node is not None:
             self.classing = classing_node.text
@@ -1008,7 +1010,7 @@ def __init__(
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name", "")
+        self.name = xml_node.attrib.get("name") or ""
         uuid = xml_node.attrib.get("uuid")
         if uuid is not None:
             self.uuid = uuid
@@ -1086,18 +1088,22 @@ class Class(BaseNode):
     def __init__(
         self,
         uuid: Optional[str] = None,
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         xml_node: Optional["Element"] = None,
         *args,
         **kwargs,
     ):
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
         self.uuid = uuid
         self.name = name
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name")
-        self.uuid = xml_node.attrib.get("uuid")
+        self.name = xml_node.attrib.get("name") or ""
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
 
     def __str__(self):
         return f"{self.name}"
@@ -1113,18 +1119,22 @@ class Position(BaseNode):
     def __init__(
         self,
         uuid: Optional[str] = None,
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         xml_node: Optional["Element"] = None,
         *args,
         **kwargs,
     ):
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
         self.uuid = uuid
         self.name = name
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name")
-        self.uuid = xml_node.attrib.get("uuid")
+        self.name = xml_node.attrib.get("name") or ""
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
 
     def __str__(self):
         return f"{self.name}"
@@ -1136,51 +1146,6 @@ def to_xml(self):
         return element
 
 
-class Symdef(BaseNode):
-    def __init__(
-        self,
-        uuid: Optional[str] = None,
-        name: Optional[str] = None,
-        geometry3d: Optional[List["Geometry3D"]] = None,
-        symbol: Optional[List["Symbol"]] = None,
-        xml_node: Optional["Element"] = None,
-        *args,
-        **kwargs,
-    ):
-        self.uuid = uuid
-        self.name = name
-        self.geometry3d = geometry3d if geometry3d is not None else []
-        self.symbol = symbol if symbol is not None else []
-        super().__init__(xml_node, *args, **kwargs)
-
-    def _read_xml(self, xml_node: "Element"):
-        self.name = xml_node.attrib.get("name")
-        self.uuid = xml_node.attrib.get("uuid")
-
-        child_list = xml_node.find("ChildList")
-        if child_list is not None:
-            self.symbol = [Symbol(xml_node=i) for i in child_list.findall("Symbol")]
-            _geometry3d = [
-                Geometry3D(xml_node=i) for i in child_list.findall("Geometry3D")
-            ]
-        else:
-            self.symbol = []
-            _geometry3d = []
-
-        # sometimes the list of geometry3d is full of duplicates, eliminate them here
-        self.geometry3d = list(set(_geometry3d))
-
-    def to_xml(self):
-        element = ElementTree.Element(
-            type(self).__name__, name=self.name, uuid=self.uuid
-        )
-        for geo in self.geometry3d:
-            element.append(geo.to_xml())
-        for sym in self.symbol:
-            element.append(sym.to_xml())
-        return element
-
-
 class Geometry3D(BaseNode):
     def __init__(
         self,
@@ -1233,13 +1198,17 @@ def __init__(
         *args,
         **kwargs,
     ):
-        self.uuid = uuid
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
+        self.uuid: str = uuid
         self.symdef = symdef
         self.matrix = matrix if matrix is not None else Matrix(0)
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.uuid = xml_node.attrib.get("uuid")
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
         self.symdef = xml_node.attrib.get("symdef")
         matrix_node = xml_node.find("Matrix")
         if matrix_node is not None and matrix_node.text is not None:
@@ -1284,11 +1253,58 @@ def to_xml(self, parent: Element):
         return element
 
 
+class SymdefChildList(Geometries):
+    # this is like the Geometries class, but called ChildList
+    def to_xml(self, parent: Element):
+        element = ElementTree.SubElement(parent, "ChildList")
+        for geo in self.geometry3d:
+            element.append(geo.to_xml())
+        for sym in self.symbol:
+            element.append(sym.to_xml())
+        return element
+
+
+class Symdef(BaseNode):
+    def __init__(
+        self,
+        uuid: Optional[str] = None,
+        name: Optional[str] = "",
+        child_list: Optional["SymdefChildList"] = None,
+        xml_node: Optional["Element"] = None,
+        *args,
+        **kwargs,
+    ):
+        self.name = name
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
+        self.uuid: str = uuid
+        self.child_list = child_list
+        super().__init__(xml_node, *args, **kwargs)
+
+    def _read_xml(self, xml_node: "Element"):
+        self.name = xml_node.attrib.get("name") or ""
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
+
+        child_list_node = xml_node.find("ChildList")
+        if child_list_node is not None:
+            self.child_list = SymdefChildList(xml_node=child_list_node)
+
+    def to_xml(self):
+        element = ElementTree.Element(
+            type(self).__name__, name=self.name, uuid=self.uuid
+        )
+        if self.child_list:
+            self.child_list.to_xml(parent=element)
+        return element
+
+
 class FocusPoint(BaseNode):
     def __init__(
         self,
         uuid: Optional[str] = None,
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         matrix: Optional[Matrix] = None,
         classing: Optional[str] = None,
         geometries: Optional["Geometries"] = None,
@@ -1297,7 +1313,9 @@ def __init__(
         **kwargs,
     ):
         self.name = name
-        self.uuid = uuid
+        if uuid is None:
+            uuid = str(py_uuid.uuid4())
+        self.uuid: str = uuid
         self.matrix = matrix if matrix is not None else Matrix(0)
         self.classing = classing
         if geometries is None:
@@ -1307,8 +1325,10 @@ def __init__(
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.uuid = xml_node.attrib.get("uuid")
-        self.name = xml_node.attrib.get("name")
+        uuid = xml_node.attrib.get("uuid")
+        if uuid is not None:
+            self.uuid = uuid
+        self.name = xml_node.attrib.get("name") or ""
         matrix_node = xml_node.find("Matrix")
         if matrix_node is not None and matrix_node.text is not None:
             self.matrix = Matrix(str_repr=matrix_node.text)
@@ -1504,7 +1524,7 @@ class Protocol(BaseNode):
     def __init__(
         self,
         geometry: Optional[str] = "NetworkInOut_1",
-        name: Optional[str] = None,
+        name: Optional[str] = "",
         type_: Optional[str] = None,
         version: Optional[str] = None,
         transmission: Optional[str] = None,
@@ -1521,7 +1541,7 @@ def __init__(
 
     def _read_xml(self, xml_node: "Element"):
         self.geometry = xml_node.attrib.get("geometry")
-        self.name = xml_node.attrib.get("name")
+        self.name = xml_node.attrib.get("name") or ""
         self.type = xml_node.attrib.get("type")
         self.version = xml_node.attrib.get("version")
         self.transmission = xml_node.attrib.get("transmission")
@@ -1546,6 +1566,10 @@ def to_xml(self):
 
 
 class Alignment(BaseNode):
+    geometry: Optional[str]
+    up: Optional[str]
+    direction: Optional[str]
+
     def __init__(
         self,
         geometry: Optional[str] = "Beam",
@@ -1589,12 +1613,12 @@ def __init__(
         *args,
         **kwargs,
     ):
-        self.universal = universal
+        self.universal = universal if universal is not None else ""
         self.target = target
         super().__init__(xml_node, *args, **kwargs)
 
     def _read_xml(self, xml_node: "Element"):
-        self.universal = xml_node.attrib.get("universal")
+        self.universal = xml_node.attrib.get("universal") or ""
         self.target = xml_node.attrib.get("target")
 
     def __str__(self):