Editing Flocking (section)

==== Rule variants ====

The basic model has been extended in several different ways since Reynolds proposed it. For instance, Delgado-Mata et al.<ref>{{Cite journal |display-authors=etal |vauthors=Delgado-Mata C, Ibanez J, Bee S |year=2007 |title=On the use of Virtual Animals with Artificial Fear in Virtual Environments |journal=New Generation Computing |volume=25 |issue=2 |pages=145–169 |doi=10.1007/s00354-007-0009-5 |s2cid=26078361}}</ref> extended the basic model to incorporate the effects of fear. Olfaction was used to transmit emotion between animals, through pheromones modelled as particles in a free expansion gas.

Hartman and Benes<ref>{{Cite journal |vauthors=Hartman C, Benes B |year=2006 |title=Autonomous boids | journal=Computer Animation and Virtual Worlds |volume=17 |issue=3–4 |pages=199–206 |doi=10.1002/cav.123 |s2cid=15720643}}</ref> introduced a complementary force to the alignment that they call the change of leadership. This steer defines the chance of the bird to become a leader and try to escape.