update

oofem_classes.py

@@ -156,9 +156,9 @@ class Element:
 class Visualizer:
     def __init__(self, struct):
         self.struct = struct
-        self.displacement_scale
-        self.symbol_scale
         self.num_elements = self.struct.get_number_elements()
+        self.displacement_scale = None
+        self.symbol_scale = None
 
 class Structure:
     def __init__(self):