Forza Motorsport 4: Under the Hood Part 6

Brian Ekberg
Thursday, March 22, 2012

Welcome to the latest installment of our series, “Forza Motorsport 4: Under the Hood”. In this edition, Forza 4 creative director Dan Greenawalt discusses the most recent title update for Forza 4, which went live today. This title update has been in the works for several months now, and includes a number of key improvements to the Forza Motorsport 4 experience. So, without further ado, let's dive in!

 

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One of the foremost issues in the community’s minds of late has been the multiplayer lobby issues in Forza 4. What happened and how does the new title update improve the game? 

With every title update we’ve released for Forza Motorsport 4, our goal has been the same: to create the best experience for the people who are playing the game. This can be anything from updates that add functionality to the game (such as raising the level cap in this title update… more on that in a bit) to correcting post-release gameplay issues that crop up. In the case of multiplayer lobby crashing, the work in this title update to address the issue was the result of several months of painstaking research and investigation.

 

Essentially what was happening was a slow memory leak when using liveried cars and jumping between lobbies. The leak was only happening when players driving liveried cars would join or leave lobbies at precisely the right moment during the loading of a race (interestingly, this is called a "race condition" in software testing). The leak occurred on all boxes even if the player didn’t have a custom livery, but it was exceedingly small. As the leak got worse over the course of a player’s session, it would cause the box to crash. This resulted in longer load times for everyone else in the lobby with that player as his crashed box timed-out. Unfortunately, the problem was made worse when players would go from one lobby to the next after becoming impatient with loading times, thus essentially "spreading" the memory leak from one lobby to the next.

 

Because of the extended steps needed to find a reliable reproduction of the problem in our testing lab, our development team put weeks of research and testing into this fix. The result was a problem that was more difficult to diagnose than it actually was to repair. In addition to all our developers’ hard work, I want to recognize and thank our dedicated community members who answered the call put out by our QA team on the FM.net forums, which provided valuable insight into this issue from the player perspective. The data we received was crucial in helping us completely isolate the problem and eventually engineer our solution. 

 

As a result of all this work, we expect lobby crashes to dramatically reduce, resulting in the kind of online experience Forza Motorsport fans have come to expect from the game.

 

You mentioned a level cap increase. How will that work? 

This is one of my favorite parts of this title update. In short, we’re bumping up the level cap in Forza Motorsport 4 from 150 to 999. Our level 150 cap was based on data we gathered from Forza Motorsport 3, and we believed it was high enough that our most hardcore players wouldn’t hit it for nearly a year. As it turns out, our fans are playing a lot more Forza than they did in the past. Our most diligent players hit the 150 level cap in a quarter of the time we expected. Is this because of Rivals Mode, Public Lobbies, World Tour? We don’t know. As a result, we’ve raised the cap significantly to give our most dedicated players something new and exciting to brag about on their player cards and within the Forza community.

 

In terms of numbers, level 150 in Forza Motorsport 4 represents 6.5 million experience points. By comparison, it will take you 875 million XP to reach level 999 (or roughly 134 times the amount of experience needed to hit the previous level cap). Once you pass the level 150 mark, leveling will progress at a relatively steady rate. Around level 400 or so, however, the XP needed to level will dramatically jump, which should provide a real test for our most loyal players. 

 

Last time, we promised some Performance Index changes after banning a handful of so-called leaderboard cars. Can you explain the new changes and the reasoning behind them? 

In our last title update, we temporarily removed the ability for eight cars to post leaderboard times, while the development team investigated some changes to our Performance Index system. In addition to the temporary removal of the cars, we performed a leaderboard wipe of all times posted by those cars.

 

For this title update, our goal was to have more competition at the top of the leaderboards among different cars. We took a look not just at the eight cars affected by the previous title update, but also any cars that we felt had exploitable PI values. 

 

Our PI calculation attempts to quantify a car’s performance by running each car on a simulated track, one that is designed to represent the "average" track in Forza Motorsport 4. Unfortunately, approximately 5 to 8 percent of the cars have powerful engines but produce exceedingly low top speeds due to stock gearing (or the stock gearing that comes as a result of a powertrain swap). As a result, these cars received an unnaturally low PI score, because they spent so much time around the simulated lap pegged at a gear-limited top speed. The fix in this title update catches any car that is gear-limited below this extremely low top speed and allows the car’s PI to increase if its top speed was less aberrant.

 

For this title update, 38 cars have had their PI scores adjusted, including the aforementioned eight cars. The full list:

 

  • 1980 Abarth 131 Abarth
  • 1965 Alfa Romeo Giulia Sprint GTA Stradale
  • 1971 AMC Javelin-AMX
  • 1969 Chevrolet Camaro SS
  • 1969 Chevrolet Camaro Z28
  • 1970 Chevrolet Camaro Z28
  • 1979 Chevrolet Camaro Z28
  • 1970 Chevrolet Chevelle SS-454
  • 1960 Chevrolet Corvette
  • 1970 Chevrolet Corvette ZR-1
  • 1966 Chevrolet Nova SS
  • 1970 Dodge Challenger R/T
  • 1969 Dodge Charger R/T
  • 1967 Dodge Coronet W023
  • 1968 Dodge Dart HEMI Super Stock
  • 1970 Dodge Coronet Super Bee
  • 1964 Ford Fairlane Thunderbolt
  • 1970 Ford Mustang Boss 429
  • 1978 Ford Mustang King Cobra
  • 1971 Ford Mustang Mach 1
  • 1973 Ford Pinto
  • 1992 Lancia Delta Integrale EVO
  • 1971 Lotus Elan Sprint
  • 1999 Lotus 1999 Lotus Elise Sport
  • 1990 Mercedes-Benz 190E 2.5-16 Evolution II
  • 1954 Mercedes-Benz 300SL Gullwing Coupe
  • 1970 Mercury Cougar Eliminator
  • 1970 Nissan Datsun 510
  • 1968 Pontiac Firebird
  • 1969 Pontiac Firebird Trans Am
  • 1977 Pontiac Firebird Trans Am
  • 1965 Pontiac GTO
  • 1969 Pontiac GTO Judge
  • 1980 Renault 5 Turbo
  • 2009 Renault Twingo Renault Sport Cup
  • 1968 Shelby GT-500KR
  • 1985 Toyota Sprinter Trueno GT Apex
  • 1984 Volkswagen Rabbit GTI

 

This PI fix will affect any and all of the above cars in your personal Forza 4 garage. In addition, any affected cars that are currently shared in your Car Club Garage will be automatically unshared and will need to be re-uploaded. Affected cars in the Auction House will not be cleared and, while PI may be temporarily incorrect when you bring an affected car into your garage (or cancel an auction), the PI will eventually be updated. 

 

In addition, tuning setup classes will be invalidated from the storefront. If you have posted a tuning setup, it will still be on the Storefront, but any claim in the description or name regarding car class may be invalid depending on the car and its adjusted PI. We suggest you re-upload your tunes with correct class descriptions.

 

Finally, while all cars will be able to post to the leaderboard, we will be performing a leaderboard wipe in the coming days for all 38 of the above cars. This will allow the leaderboards to accurately reflect the post-title update PI changes.

 

What other improvements does this title update include? 

This title update fixes an interaction between our save game volume and the Xbox file system which was causing slow navigation problems when navigating car menus in Forza 4. As a result, players will see noticeably quicker UI navigation when in their Forza Motorsport 4 garages or in other car select menus. While this fix will not shrink your save game size, it will slow or halt the growth of your save game.

 

IMPORTANT NOTE: Because we are doing some behind-the-scenes work on your online profile (including PI re-assignment and removing orphaned thumbnails for car select menu navigation), your initial sign-in for Forza 4 upon the application of our latest title update might take longer than usual, upwards of a full minute if your Forza 4 garage is full of cars affected by the PI changes. This should only happen the one time.