Kangaroo Legends

CARELESS CODE RECYCLING CAUSES KILLER KANGAS
 Mutant Marsupials Take Up Arms Against Australian Air Force

 The reuse of some object-oriented code has caused tactical headaches
 for Australia's armed forces. As virtual reality simulators assume
 larger roles in helicopter combat training, programmers have gone to
 great lengths to increase the realism of their scenarios, including
 detailed landscapes and - in the case of the Northern Territory's
 Operation Phoenix- herds of kangaroos (since disturbed animals might
 well give away a helicopter's position).

 The head of the Defense Science & Technology Organization's Land
 Operations/Simulation division reportedly instructed developers to
 model the local marsupials' movements and reactions to helicopters.
 Being efficient programmers, they just re-appropriated some code
 originally used to model infantry detachment reactions under the
 same stimuli, changed the mapped icon from a soldier to a kangaroo,
 and increased the figures' speed of movement.

 Eager to demonstrate their flying skills for some visiting American
 pilots, the hotshot Aussies "buzzed" the virtual kangaroos in low
 flight during a simulation. The kangaroos scattered, as predicted,
 and the visiting Americans nodded appreciatively... then did a
 double-take as the kangaroos reappeared from behind a hill and
 launched a barrage of Stinger missiles at the hapless helicopter.
 (Apparently the programmers had forgotten to remove that part of the
 infantry coding.)

 The lesson?

 Objects are defined with certain attributes, and any new object
 defined in terms of an old one inherits all the attributes. The
 embarrassed programmers had learned to be careful when reusing
 object-oriented code, and the Yanks left with a newfound respect for
 Australian wildlife.

 Simulator supervisors report that pilots from that point onward have
 strictly avoided kangaroos, just as they were meant to.

 -- From June 15, 1999 Defense Science and Technology Organization
    Lecture Series, Melbourne, Australia, and staff reports

29 November 1999

On Friday DSD told the story of the killer kangaroos. Now we know the
truth. And it is even weirder: the kangaroos threw beach balls!

Dr Anne-Marie Grisogono, Head, Simulation Land Operations Division at
the Australian DSTO has told us what actually happened and we are
delighted to set the record straight.

"I related this story as part of a talk on Simulation for Defence, at
the Australian Science Festival on May 6th in Canberra. The Armed
Reconnaissance Helicopter mission simulators built by the Synthetic
Environments Research Facility in Land Operations Division of DSTO, do
indeed fly in a fairly high fidelity environment which is a 4000 sq km
piece of real outback Australia around Katherine, built from elevation
data, overlaid with aerial photographs and with 2.5 million realistic
3d trees placed in the terrain in those areas where the photographs
indicated real trees actually exist.

"For a bit of extra fun (and not for any strategic reason like
kangaroos betraying your cover!) our programmers decided to put in a
bit of animated wildlife. Since ModSAF is our simulation tool, these
were modelled on ModSAF's Stinger detachments so that the associated
detection model could be used to determine when a helo approached, and
the behaviour invoked by such contact was set to 'retreat'. Replace
the visual model of the Stinger detachment in your stealth viewer with
a visual model of a kangaroo (or buffalo...) and you have wildlife
that moves away when approached. It is true that the first time this
was tried in the lab, we discovered that we had forgotten to remove
the weapons and the 'fire' behaviour.

"It is NOT true that this happened in front of a bunch of visitors
(American or any other flavour). We don't normally try things for the
first time in front of an audience! What I didn't relate in the talk
is that since we were not at that stage interested in weapons, we had
not set any weapon or projectile types, so what the kangaroos fired at
us was in fact the default object for the simulation, which happened
to be large multicoloured beachballs.

"I usually conclude the story by reassuring the audience that we have
now disarmed the kangaroos and it is again safe to fly in Australia."