Fixed how dimensions of all-atom structures are set

mrdna/model/arbdmodel.py

@@ -1017,7 +1017,7 @@ tclForcesScript $prefix.forces.tcl
         if update_dimensions:
             format_data['dimensions'] = self.dimensions_from_structure()
 
-        for k,v in zip('XYZ', self.dimensions):
+        for k,v in zip('XYZ', format_data['dimensions']):
             format_data['origin'+k] = -v*0.5
             format_data['cell'+k] = v