virtual SnapType get_default_snap_type_to(const Object &) const { return NO_SNAP; }
public:
+ virtual unsigned get_n_link_slots() const { return 0; }
+ virtual Object *get_link(unsigned) const;
+ virtual int get_link_slot(const Object &) const { return -1; }
+ virtual bool link_to(Object &) { return false; }
+ virtual bool break_link(Object &);
+ virtual bool break_link(unsigned) { return false; }
+ virtual void break_links();
+
virtual bool collide_ray(const Vector &, const Vector &) const = 0;
};