diff --git a/src/polyphy/core/discrete3D.py b/src/polyphy/core/discrete3D.py
index a74359f..71e8666 100644
--- a/src/polyphy/core/discrete3D.py
+++ b/src/polyphy/core/discrete3D.py
@@ -51,9 +51,10 @@ def register_data(self, ppData):
 
 class PPInputData_3DDiscrete(PPInputData):
     # TODO: load datasets from specified file + type
-    def __init__(self, input_file=None):
+    def __init__(self, input_file=None, rng=None):
         super().__init__()
         self.input_file = input_file
+        self.rng = rng
 
     def __load_from_file__(self):
         if self.input_file is None: