Video: Rally Cross Physics

[Morgan Ramsay]

International Game Developers Association, San Diego, recently released the video for Rally Cross Physics (http://www.igda-sandiego.org/web/2007/08/video-rally-cross-physics/)—a presentation by Jim Buck, chief executive officer at Twitchy Thumbs Entertainment (http://www.twitchythumbs.com/), on the physics of Rally Cross for the PlayStation.

In the presentation, Jim Buck discusses "the methods used to develop the physics of Rally Cross and how they were achieved with limited resources available on the PlayStation. He focused on lessons learned, resourcefulness, and why tricks for 'old dogs' are still relevant to today's projects despite advances in technology."

You can also find the presentation slides and photos of the event at the International Game Developers Association, San Diego, and Twitchy Thumbs Entertainment websites.

[ChrisP]

Interesting, thanks for posting this. I always like hearing about alternate methods for physics simulations. :)

For those without an hour to spare to watch the video: Rally Cross represented each car as 8 vertices connected by springs - rather than tracking angular/linear effects separately, which is the usual approach taken for rigid body physics. The effect is likened to driving a slab of Jell-O around.

I wonder if Gish used a similar approach for its player character physics. Though Gish had a lot more going on of course; I seem to remember it had rigid bodies and such as well. Not to mention the whole wall-climbing thing (but that's a control issue more than a physics issue I guess - you just have to figure out what forces to apply to your system and your existing physics code takes care of the rest).

[Jim Buck]

Glad someone enjoyed it.

Yeah, Gish definitely was doing something similar for the Gish character. In fact, not toooo long ago, there was an article in Game Developer discussing creating a Gish-like character (maybe a year ago?).

[Michael Flad]

The GDMag article from Mick West can be found on his website ...

http://cowboyprogramming.com/2007/01/05/blob-physics/

[duck]

I had many hours of fun playing Rally Cross on the Playstation I. It was (still is) a great game. It's a treat to see how the physics was done. Thanks Jim!

[Jim Buck]

No problem. I still dig playing it myself. There is also this article from a while back in Game Developer magazine and now on Gamasutra that discusses this same method of physics:

http://www.gamasutra.com/features/20000208/lander_01.htm

[Bad Sector]

Heh, nice to see that the first thing i thought about "physics" (keeping vertices connected with some kind of springs :-) is actually used somewhere with success.

Unfortunatelly my first naive implementations of the idea were a disaster, so i just thought that the whole thing was not what others are really doing and i abandoned the idea :-P.