Mar. 30, 2001 Xiaoyuan Tu and Demetri Terzopoulos, Dept. of CS, University of Toronto Artificial Fishes: Physics, Locomotion, Perception, Behavior Presentation by Siddharth Dalal

Intro & Background What do fish do? –eat, survive, when compelled by their libidos…. Physics based graphic modeling Worm Dynamics, facial model –more sophisticated spring mass model advanced behavioral animation Any fish is good if caught on the hook.

Overview Intention focuses sensory data causing behavior

Fishics 1 - Mechanics Spring Mass Model m = mass x = position q = damping factor w = net force due to springs f = external force

Fishics 2 - Hydrodynamics Swimming - Muscles + Hydrodynamics

Fishics 3 - Motor Controllers Swim MC Left and right MC Anterior and Posterior of fish - r1, s1, r2, s2 Max params scaled from to produce varying speeds

Sensory Perception Two on board environment sensors: –Vision Sensor - extracts information from scene geometry, object database, physical simulation. Cyclopean(?) vision o viewing angle. –Temperature sensor - senses ambient temp. at center of body

Behavio(u)r 1 Intention based on –Habits –Mental State –Incoming Sensory Information decides behavior routine incremental - needs memory

Behavior 2 - Habits and Mind Habits - does fish like brightness, schooling, male or female (yes this is in habits) Mental State –Three mental states - HLF - hunger, libido, fear –H= min[1-n(t)R(Δt)/α, 1] –L=min[s(Δt)(1-H(t)), 1] –F=min[Σf, 1], f=min[D/d(t), 1] (Fish like sex after dinner )

Intentions 1 Intentions –avoid, –escape –school –eat –mate –leave –wander

Intentions 2 Features of Generator –Persistence in intentions - no dithering –focusser - focus on most important intention Create ‘abnormal fish’ –warp intentions

Intentions 3 Behavior routines: –eight - avoid static obstacle, avoid fish, eat, mate, leave, wander, escape, school –chasing target subroutine –other subroutines - looping?, circling, ascending?, nuzzling

Fish Type = Warped Intentions Artificial Fish Types –Predators don’t escape, mate or school always cruise, so don’t leave

Fish Type = Prey Fish Grey Fish Artificial Fish Types –Prey school evade predators

Pacifists Artificial Fish Types –Pacifist no school, no escape just mate complex mating behavior implemented… –fish i chooses partner j –criteria if i is female/male –looping, circling, chasing-target, nuzzling –etc.

Result 10 fish, 15 food particles, 5 static obstacles at 4fps on SGI R4400 Indigo2 Future: –reproduction –other work

Links

Guests and fish start to stink after two days.