diff --git a/geometry/__init__.py b/geometry/__init__.py
index ceb3a04..e50e3c0 100644
--- a/geometry/__init__.py
+++ b/geometry/__init__.py
@@ -1,9 +1,11 @@
 if "bpy" in locals():
     import importlib
+    importlib.reload(node_tree)
     importlib.reload(node_settings)
     importlib.reload(operator)
     importlib.reload(ui)
 else:
+    from . import node_tree
     from . import node_settings
     from . import operator
     from . import ui
diff --git a/geometry/node_tree.py b/geometry/node_tree.py
new file mode 100644
index 0000000..64be218
--- /dev/null
+++ b/geometry/node_tree.py
@@ -0,0 +1,8 @@
+from bpy.types import GeometryNodeTree, GeometryNodeSimulationInput
+
+from ..ntp_node_tree import NTP_NodeTree
+
+class NTP_GeoNodeTree(NTP_NodeTree):
+    def __init__(self, node_tree: GeometryNodeTree, var: str):
+        super().__init__(node_tree, var)
+        self.sim_inputs: list[GeometryNodeSimulationInput] = []
diff --git a/geometry/operator.py b/geometry/operator.py
index d1893a9..79f9cf1 100644
--- a/geometry/operator.py
+++ b/geometry/operator.py
@@ -7,8 +7,8 @@
 from io import StringIO
 
 from ..ntp_operator import NTP_Operator
-from ..ntp_node_tree import NTP_NodeTree
 from ..utils import *
+from .node_tree import NTP_GeoNodeTree
 from .node_settings import geo_node_settings
 
 class NTPGeoNodesOperator(NTP_Operator):
@@ -46,7 +46,7 @@ def _process_sim_output_node(self, node: GeometryNodeSimulationOutput,
             attr_domain = enum_to_py_str(si.attribute_domain)
             self._write((f"{inner}{si_var}.attribute_domain = {attr_domain}\n"))
 
-    def _process_node(self, node: Node, ntp_node_tree: NTP_NodeTree,
+    def _process_node(self, node: Node, ntp_node_tree: NTP_GeoNodeTree,
                       inner: str, level: int) -> None:
         #create node
         node_var: str = self._create_node(node, inner, ntp_node_tree.var)
@@ -121,7 +121,7 @@ def _process_node_tree(self, node_tree: GeometryNodeTree,
         #initialize nodes
         self._write(f"{inner}#initialize {nt_var} nodes\n")
 
-        ntp_nt = NTP_NodeTree(node_tree, nt_var)
+        ntp_nt = NTP_GeoNodeTree(node_tree, nt_var)
 
         for node in node_tree.nodes:
             self._process_node(node, ntp_nt, inner, level)