+ Spring (Real distance, Real min_distance);
+
+ Real distance () const {return distance_;}
+ Real min_distance () const {return min_distance_;}
+ Real inverse_stretch_strength () const {return inverse_stretch_strength_;}
+ Real inverse_compress_strength () const {return inverse_compress_strength_;}
+ Real blocking_force () const {return blocking_force_;}
+
+ Real length (Real f) const;
+
+ void set_distance (Real);
+ void set_min_distance (Real);
+ void set_inverse_stretch_strength (Real);
+ void set_inverse_compress_strength (Real);
+ void set_blocking_force (Real);
+ void set_default_strength ();
+
+ void operator*= (Real);
+ bool operator> (Spring const&) const;