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Wednesday, 27 February, 2002, 16:54 GMT
Games fizz with proper physics
Artwork from Warcraft 3, Blizzard Entertainment, Blizzard
Games like Warcraft 3 are getting better physics
Every computer game takes place in a world far removed from this one, but the carefully constructed fantasy often falls apart because game elements avoid the basic laws of physics.

Sometimes you want to be able to take a left turn at 400 mph

Paul Hayes, Havok
Every game player has seen computer controlled foes merge briefly with walls or doors or huge explosions that leave walls and windows unscathed.

Many designers are now turning to specialised software, known as a physics engine, to ensure they do a much better job of describing the world and to make their creations more realistic.

Paul Hayes, a spokesman for physics engine maker Havok, said explosions and other effects were often used by some games makers to hide the fact that objects did not interact properly.

Action and reaction

Typically, every game has its own crude, custom-built physics engine. But slipshod programming can mean that touching objects, such as an arm and a wall, merge instead of staying distinct.

Screen shot from Grand Theft Auto 3, Take 2 Interactive
Collisions are all part of the fun
"All games designers know enough basic physics to keep the car on the track," said Mr Hayes, "but it's time-consuming and they are re-inventing the wheel every time."

To avoid this, many designers are turning to specialists like Havok and Math Engine who do nothing but work out the best way to translate the real world into software.

Havok's physics engine emerged out of computer science research done at Trinity College, Dublin, by its founders Hugh Reynolds and Stephen Collins.

No soft drinks

Physics engines model collisions between rigid and malleable objects, make cloths and fluids flow convincingly and capture the movement or reaction of softer, jointed objects like people.

Before now, said Mr Hayes, many of the objects in a game world were single use; ladders are for climbing, crates can either be destroyed or climbed on, and an empty gun cannot be used as a club.

Some games, such as the acclaimed Half-Life, use these restrictions to give hints about how a player should proceed. But, in many other games, these limits are irritating.

"In Deus Ex, players liked being able to break the Coke machine, but hated the fact that they couldn't pick up and use the cans in some way," said Mr Hayes.

Story bored

By using a specialist physics engine, all objects become useable because the hard work of figuring out how they interact with each other has been done.

Gorillaz Shockwave game, Gorillaz
Rock band Gorillaz are using the physics engine in an online game
"Players want to be able to use any object in a scene like they would in real life," said Mr Hayes.

Already 50 games makers have signed up for the Havok engine and it is being used in high-profile titles such as Warcraft III and Deus Ex 2. Even the virtual rock band Gorillaz is using it for a driving game on its website.

More realistic physics could have a profound effect on how people play games too. They no longer had to be linear stories that players are guided through, said Mr Hayes, instead they became more open-ended and non-deterministic.

Quick getaway

Havok does acknowledge, however, that too much reality can sometimes get in the way of a good game.

"It's more about a consistent world rather than the real world because the real world can be a pain in the neck," said Mr Hayes.

One game designer was forced to be less true to reality because guns carried by players kept catching on doorways and windows.

"And," said Mr Hayes, "sometimes you want to be able to take a left turn at 400 mph."

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