+ Simple_spacer ();
+
+
+ void my_solve_linelen ();
+ void my_solve_natural_len ();
+ Real active_springs_stiffness () const;
+ Real range_stiffness (int, int) const;
+ void add_rod (int l, int r, Real dist);
+ void add_spring (Real, Real);
+ Real range_ideal_len (int l, int r) const;
+ Real active_blocking_force ()const;
+ Real configuration_length ()const;
+ void set_active_states ();
+ bool is_active () const;