Drivatar™ in Forza Motorsport
Drivatar™

Drivatar™ technology is at the heart of all the computer opponents in Forza Motorsport, and is the basis for the novel "Train Drivatar" feature in the game.

Introduction

Remember the days when games came with nice big manuals you could read at bedtime? The pamphlets we all get these days are OK and just about fit-for-purpose, but they do not really tell us as much as we would like. That is why we have put together this web-site, and why we have written this section in particular. Consider this page an extension to the unavoidably concise Drivatar section in the Forza Motorsport manual.

The Drivatar – what is it?

We suggest you think of your Drivatar as a clone of yourself. It is a replicant, a Driving Avatar made to your very own recipe. You teach it to drive like you do and you can keep on training it until it reaches the dizzy heights of perfection. Well, as perfect as you can make it that is. Drivatars are rather like your own culinary concoctions, they are only as good as you are and whilst you may have followed the recipe from the TV-chef-of-the-moment’s new book to the letter, that Moroccan-lamb-served-on-a-bed-of-organic-rice-and-sunflower-seeds will always have your own unique slant on the theme. Drive erratically, braking and apexing too late and so will your Drivatar. Drive consistently with early braking, fast apexing and fast corner exit and so will your Drivatar. It really is a realistic model of your own driving skills.

Why create a Drivatar? What will it do for me?

What is it for? Well aside from being a really interesting scientific problem for "research" , it’s a novel addition to the gameplay of Forza. For one thing, all those computer opponents in "Career" and "Arcade" races are Drivatars that were pre-trained by computer – that is one of the reasons why they drive far more realistically than typically seen in racing games. For another, you can employ Drivatars to race for you in any Career Races that you are having trouble with or do not want to bother with (did I hear someone say "endurance"?). You can even pursue an entire career via your Drivatar. For some real fun though you can create a custom race in Head to Head using any combination of cars, tracks and drivers – including friends' Drivatars, your own Drivatars and the standard AI opponents in the game.

Drivatar Lessons

When you first create your Drivatar, it knows nothing about your driving style and you need to take time to nurture your protegé. The easiest way to teach it to race like you is to invite it into the passenger seat of a few different cars and let it observe how you drive.

Forza’s approach to getting you to spend quality time with your Drivatar is to impose five lessons on you. You get to take your Drivatar out in a cunningly selected variety of cars on an even more cunningly selected variety of tracks. In fact, if you are itching to test drive a Class R car and have not had time to unlock everything in the game yet then this is a sly backdoor into achieving just that since you will get to drive an Audi R8 in lesson five! The lessons are devilishly cunning because they shoe-horn you into teaching your Drivatar how you drive a representative sample of corner types that appear throughout the game. These corner types are listed in the manual for you and once you have completed all five lessons you will have taught your Drivatar how you drive each and every corner type in the game (with the exception of one – see Free Training to fix that). More importantly, you will have taught your Drivatar some key characteristics of your driving style:

    • Variety – how consistent are you?
    • Line – how smoothly do you guide the car around corners and through combinations thereof?
    • Entry speeds and braking points – how early do you brake before entering a corner? Are you conservative? Reckless?
    • Apex speeds and positions – how close are you to the apex of the corner and how fast are you going?
    • Exit Speeds and acceleration points – when do you start accelerating as you leave a corner and how well have you maintained your speed around the corner?

We use all this information to learn a model of your driving characteristics and that model is what drives the Drivatar.

The lessons are a pretty good way of learning some of the tracks and how to drive; as well as the route to training your Drivatar. You got full ghost access, you got the Scores, the lap times, best laps – a veritable cornucopia of information on how to improve your driving. Think of the lessons as a cunningly disguised "driving school" as well as the implementation of what we would claim is the most sophisticated machine learning ever seen in a video game!

Each lesson is three laps. There is a reason for that – we need a representative sample of your driving style to learn a driving model and three laps is pretty much the minimum useful amount of data. Ideally, to build a better model of your driving we need more, and indeed if you train further on the same track, your Drivatar will make use of that additional data.

You can quit a lesson early and depending on how many laps you have completed, there are two possible outcomes:

    • You will be informed that you have provided insufficient data for your Drivatar to learn anything useful, and your Drivatar will not be updated. Typically you need to complete a little more than one lap of good (i.e. mainly on the track!) driving, though the game is a little less strict on the Nurburgring.
    • You will have contributed to the Drivatar’s training (your data will be assimilated by the model), but you will not have completed the lesson and you will have to try again at another time.

Once you have completed a lesson (i.e. the full 3 laps) a giant blue tick mark will scythe through the lesson icon – this does not mean you cannot do it again though: feel free to repeat and improve.

Once you have completed all five lessons your Drivatar is considered “Mature”. That is the term we use to indicate that it has had sufficient training to reproduce a reasonable approximation to your driving. You should not consider your Drivatar complete at this stage (far from it!) – that is why we use the term “mature”, it indicates it has progressed from its enthusiastic teens and into the first flush of adulthood. You will now see some more menu options unlocked: Free Training and Head to Head. You will also now be able to employ your Drivatar to race for you in Career Races should you so choose. More on this later. Coming back to the point on completing your Drivatar, we should point out that a Drivatar is never really “complete”, it can always be improved. You would be surprised how much your own style progresses as you progress through the game and how you make subtle changes in different cars and on different tracks. Drivatars are like a partner, you need to give them constant love and attention to get the best from them. You can skip the chocolates though.

Scores on the Doors

As covered in the printed Forza manual, as you train your Drivatar, you are graded on how well you drive certain types of corner on each track. Let us talk a little more about those scores.

When you create your Drivatar you will see a menu option on the Drivatar menu called “Statistics”. If you visit this screen before you begin the lessons you see three tabs.

    • A "Career" summary page showing "Distance Driven" etc. Note that all these statistics here refer to Career Races driven by that Drivatar not the amount of driving during training.
    • A summary of the Drivatar's turn abilities. This is specific to the training.
    • A summary of the Drivatar's ability in various car categories, again specific to training.

The second tab is probably the most important – it lists all the corner types categorised in the game ("Kink", "Constant Radius" etc) along with your current average scores. These are all 0% to begin with. As you train your Drivatar, either via "Drivatar Lessons" or "Free Training", these scores will change. They are the current values of the running averages of the scores you have achieved for each corner type and will change rapidly to begin with but, being averages, obviously stabilise the more you drive. Let us take a look at one of those score messages you might see in the game:

Constant Radius 73% (+5)

Obviously the first part refers to the corner you just drove around. The “73%” refers to the absolute score you just achieved for that single corner. The “(+5)” refers to the fact that, compared to your score at the start of the race, you improved by a margin of 5%. Your previous score of record therefore was 68% - though the messages are rounded to the nearest whole number.

The 73% is calculated based on a number of key characteristics concerning the line and speed maintained through the corner. Roughly speaking, percentage points are awarded for entry speed, exit speed, closeness to apex, smoothness of line and time taken through the corner. Note that you do not have to be perfect according to all these metrics in order to score 100%.

Now, the talented drivers amongst you will rightly be shouting “but I drove that corner perfectly and did not get 100%”. That is a fair comment, since no scoring system can be perfect, and Drivatar Statistics are no exception. But you will also appreciate that for the majority of people for the majority of the time it gives a very reasonable and meaningful score. If you are genuinely talented (and that doesn’t mean 50% of you!!) then you should not get too hung up on your scores. In particular, please note that the scores are only indicative. The Drivatar itself is not concerned with the scores; it is concerned with your speed and position at every point on the track and of course your consistency. The scores are just a useful indicator of how well most people are doing and do not directly affect how well your Drivatar will perform in races.

Note that if, at the end of a lesson or some free training, you choose to "discard" your efforts, your statistics will not be updated.

Observe

Once you have completed at least one Drivatar lesson, entering "Observe" mode allows you to watch your Drivatar drive on any of the five tracks where the lessons have been completed. This allows you to assess you Drivatar's performance and perhaps see how your own driving might be improved to take advantage of any traits you observe in your Drivatar. Once you have completed all the lessons and your Drivatar is mature you will be able to watch it drive at any circuit in the game (another cunning back door – this time to checking out the locked tracks in the game) in any car in your garage. This is where you can start to appreciate the technology behind the Drivatar. The Drivatar is not a simple recording of your driving specific to the track and car combination from the lessons. Instead, your Drivatar infers a probabilistic model of your "style" of driving in general by monitoring your line with respect to the geometry of the track, and your speed with respect to the capabilities of your car.

Think about it ... you have trained your Drivatar to drive on 5 different tracks in 5 particular cars and now it is able to drive all the tracks in the game in all cars – though effectively it has never experienced them before. If you think that is simple, think again! What has just happened is that you have trained a computer how to drive any track in the game just by driving 3 laps of 5 tracks. In "machine learning" terms that is almost miraculous! In order to train a computer how to do the most menial of real world tasks we typically have to provide hundreds of thousands of examples of data.

Free Training

Once you have completed all the Drivatar lessons and your Drivatar is mature, "Free Training" is unlocked and you are able to continue training it on any track in the game using any car in your garage. This is where your Drivatar can start to really work for you. The more you train it, the better it will get.

The most noticeable change will come if you train it at new tracks it has not raced before. After the lessons are complete, try observing your Drivatar at Laguna Seca for example. It will do OK, perhaps as well or better than you would when driving that circuit for the very first time. But, of course, the expert driver requires specific knowledge and experience of the idiosyncrasies of a given track to really perform well and the infamous “corkscrew” at Laguna Seca is a great example. Make a note of the best observed lap time your Drivatar achieves at Laguna Seca and then do some training there. Repeat the observe experiment and, assuming a reasonable level of competence on the part of the trainer, you should see the best lap time improve significantly. To get the very best from your Drivatar, you really need to consider repeatedly adding to its training as you progress through the game and turn your attentions to specific cars and events. For example, your initial training at Tsukuba in the Ford Focus will allow your Drivatar to drive a Porsche GT3 there reasonably well but once you have progressed to that class of car in the game, you will really need to refresh the training to get the very best from your Drivatar at that level.

Also, Free Training is the place where you can update your Statistics and get scores for any corner type(s) not included in the tracks featured in the lessons.

Head to Head

Head to Head racing is easy to overlook in Forza given the vast swathes of arcade races, career races and online options open to you, but this is an innovative and exciting feature of the game. When was the last time you could completely customise a race to your precise requirements? Not only can you customise the track and the field of cars, you can personalise each and every driver. A great way to use the Head to Head races is to race your friends' Drivatars – simply get them to copy their Drivatar to a memory unit from the Xbox dashboard, and then copy it to your own console. Once on your Xbox hard disk, you can then race against it in Head to Head mode – how cool is that! Get a bunch of friends to all dump their Drivatars to your console and vice-versa and you can all continue to race against each other and learn each other’s lines and techniques without them being present (or on Xbox Live). In summary, you can specify races against:

    • Your currently selected Drivatar (which will be mature by default)
    • Any other mature Drivatars you may have created
    • Any other mature Drivatars created by other players (i.e. under other profiles) on your Xbox
    • Any mature Drivatars copied to your Xbox
    • Any of Forza's built-in AI Drivatar competitors, at "easy", "medium" or "hard" level

Head to Head is also a great way of learning where you can improve your own driving, simply configure a field of your own Drivatars in a mix of similarly specified cars and you can race against multiple versions of yourself and see where you can improve your lines or braking points by battling head to head against yourself. Or, for the ultimate personalised racing challenge, try racing your own Drivatar while giving them the benefit of a slightly faster car.

Career Races 

This is where your Drivatar gets to work for you and you can reap some financial reward and game progress for your efforts. At the beginning of each career race, a pre-race “start” menu is presented to you. There you will see the tantalisingly labelled “Load Drivatar” option. Once you have one or more locally-trained mature Drivatars available for that profile on your Xbox you can use this option to enter a Drivatar into the race for you. By “locally-trained” we mean that the Drivatar has to have been created and trained on the Xbox you are using at that time. What we did not want to see were people using Drivatars trained by other people to unlock tracks and cars for them – in other words cheating! So, in summary, to be able to enter a Drivatar in a career race, it must be:

    • Mature
    • Created on that physical Xbox
    • Created and trained under the current profile

Once you have selected a valid Drivatar from the menu, you have hired your Drivatar to race for you in the selected career race. (you can subsequently "unload" your Drivatar if you change your mind). By default you will be presented with “Live TV” style coverage of the race once it starts. Remember, this is not a replay; this is now a “live” race with your Drivatar racing for you (and if you re-run the race, the outcome may be completely different). Watch your Drivatar battle with the opposition, observe where it is driving well or badly and learn from the experience. You can always use what you just learned to refresh your Drivatar's training at that race track and in the current car.

Once the race is complete, you will have to pay a proportion of any earnings to the Drivatar as its fee for risking life and limb for you but you will still earn some credits and reap the rewards of any unlocks or prize vehicles. You can look at how many credits your Drivatar has earned and other stats like how many races it has entered and won on the first tab in the Drivatar Statistics screen. We have tended to notice that Drivatars are pretty stingy with their earnings and tend not to spend them on anything other than pies, chips and mushy peas – though it has been rumoured that some trainers have managed to secure interest free loans for desirable wheels the Drivatar might want to drive for you.

Maturity

As noted earlier, when your Drivatar has completed all 5 lessons, it is considered to be "mature". The consequences of this are, in summary:

    • Free Trainingis unlocked.
    • Observe mode is expanded, in that you can now select from any track in the game, not just those tracks for which lessons have been completed.
    • Head to Head is unlocked.

Copying Drivatars from Xbox to Xbox

Any Drivatar created on your Xbox we term to be "local". However, you can copy other "non-local" Drivatars to use in the game. Using the Xbox "dashboard" you can copy any Drivatar from the Xbox hard disk to a memory unit. From there, it can be copied to any other Xbox where it may be used subject to these limitations:

The main point of copying a Drivatar is hopefully obvious: it is to race against him or her in a custom Head to Head race. If you like, you can also Observe a copied Drivatar and examine its Statistics.