HL Rally Team Discovers Online Racing Ain’t Easy

The Original HL Rally

As seen at Blue’s News, the HL Rally 2 project, a rally racing mod for Half-Life 2, has been sadly dropped. Under development since early 2005, the mod planned to do for the sequel what HL Rally did for the original: namely, deliver some fun online racing action.

Given the stock game’s inclusion of reasonably realistic handling vehicles, one might be inclined to think that this would be even easier than the predecessor. That’s as may be when it comes to offline action, but it’s apparently in the online realm where things went wrong. The official HL Rally 2 site lists the problems they were encountering:

  • Vehicles were controlled by the server making them latent and not fun to play on the Internet
  • Predicting the vehicles on the client failed as the client and server simulate the physics differently, causing the vehicles to get rapidly out of sync
  • Correcting the predicted vehicles position made the game feel unresponsive and caused the vehicle to travel unexpected paths
  • Valve themselves said that it was currently impossible to predict and therefore network vphysics objects accurately (think of the barrels in CS).
  • The SDK does not allow for direct modification of physics
  • Could not implement manual transmission due to SDK limitations
  • RPM calculations were erratic and more often than not incorrect
  • RPM values could not be recalculated accurately

This list of issues should sound awfully familiar to those who have spent any time racing online in many ISI-based games like F1 2002 or GTR, namely warping and other related issues. It’s a shame this one won’t be available for offline racing at least.


Freelance journalist and software architect based in Upstate NY. I write for a variety of different places (as you’ll see) -- maybe even for you if you ask nicely.

One Comment

  1. I remember following the progress on HL Rally for the original Half-Life. Must have been 2001 or 2002. While it’s certainly sad that they can’t finish what they set out to do, I’m not sure it would have attracted a sustaining community.

    What I like though, as I’ve mentioned in other places a few times, is leveraging the Source engine into a racing sim. SOTA graphics with great performance, solid netcode, extensive audio engine and reliable rigid-body physics in a fairly stable package should make a good base for a racing sim. Same probably goes for UE3, the de-facto standard in engines or middleware for upcoming games it seems.

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