Is there any hope for the AI on dirt ovals?

[aasasd]

I installed several highly-rated dirt-oval mods from RFC, a few tracks from RFC (that were still available) and a couple track packs from the TrippTeam server. And I almost completely fail to get any semblance of decent racing with the AI. So far, with ‘321 Bandit Sprint Cars’, out of 48 tracks that I've tried, the AI can be said to drive properly well on three. On the rest, at best the AIs drive too slowly even at high strength settings, and are easy to overtake despite my noob skills with dirt ovals. Mostly, however, they just swerve randomly, running into the walls or off the track, colliding with each other and the player, generally getting in the way of others, and not doing any actual driving.

I haven't tried all of the same tracks with other mods, but various attempts show exactly the same problems.

Is there some trick that would make the AI run well? Or are these tracks made solely for multiplayer?

The consistency of problems between mods, plus what I heard about the AI before, suggest that this is a fault with the tracks, and I just need to leaf through them until I gather a few good ones. However, perhaps I don't know something about choosing the mods and matching them to tracks. Neither the mods nor the tracks mention which pairings should work, maybe with a couple exceptions. It would be understandable if the AIs worked when the mod matches the tracks—but instead, 321 Bandit cars are poor on 321 tracks, and DWD Late Models are poor on DWD tracks.

I've heard about the technology of ‘training’ the AI, but it sounds rather suspect to me: I hoped instead that people who know more about dirt racing would put some of that knowledge into their mods and tracks, so I could judge my novice attempts by the AIs' performance—instead of getting some generic AI driving that the ‘calibration’ should deliver.

It's kinda awkward when NR2003 tends to have better AI on dirt ovals than rFactor—even if they just drive the same as on pavement—considering that rFactor has a much wider ‘range’ of physics, so dirt racing and various weird cars feel better in it. However, I also noticed that offroad cars in general tend to have questionable AI, so maybe the game just can't cope with them—though again there's difference between tracks.

Mods that I've tried so far:
- DirtWorks Designs Late Models 2011
- DirtFactor Late Models
- SPR USAC National Midgets 2
- 321 Bandit Sprint Cars 1.0
- SPR POWRi Midgets 2014

 

[aasasd]

What I learned so far: if I enable the autopilot and watch it drive laps, I can see firsthand what the AI is doing. Turns out, on many tracks the car swerves right before the turn, in the characteristic motion of a Scandinavian flick. There may also be a second swerve on the straight for some reason. These swerves are where the AI cars lose control and run into the wall or collide with each other.

However, at least with 321 Bandit Sprint Cars, this behavior varies between tracks—on those where the AIs can drive around the track without problems, there's less or none of the swerving. My guess is that track authors indeed built their vision of proper dirt racing into the AI's racing line—but, since Bandit cars are very light and plenty powerful, they swerve too much and lose control. So the prescribed AI trajectory on a track is necessarily made for some particular mod, or at least for cars that are close-ish in power-to-weight and handling.

I switched again to heavier DirtFactor Late Model cars, and the AI does a lot better on some of the tracks that were a challenge for Bandit cars. They don't lose the rear too much, and don't end up driving across the track instead of just skidding a bit. (In fact, I had to lower the AI strength way down to 75%, instead of running it at 110-120%, like with Bandit cars—but that might be just a poor default setup, or these particular tracks may have exceptionally strong AI.)

So, it appears that I will now have to again check each track for whether it can be properly used with DirtFactor late models—I'm sure that the cars still have trouble on some of the tracks. And I'll need to do the same with any other mod that I'll want to use—bruteforcing my way through the table of the tracks and the mods.

I wonder whether the game's AI has any inbuilt understanding of driving on off-road surfaces—or at least provides some for mods. Notably, with the DirtFactor cars, the AI does some drifting even on tracks where Bandit cars drive undeviatingly on the line.

 

[Daveybird]

It depends on the mod. I think at some point, many dirt oval modders gave up on the AI, and just focused on multiplayer. So the physics the player uses for a lot of them breaks the AI, they can barely complete a lap if the game hasn't already CTDed out. Some, like BOZ Sprint Cars and DirtMotorsport 16 Late Models, have dedicated AI cars you must select in your opponents list to keep the AI stable. Others, like DirtWorks Designs and mine, have AI compatibility with every car. There was a site called The Dirt Pile, which had many of the old and more recent dirt mods. It probably closed, but it's on Archive.org and if you trim the archive.org parts out, its MediaFire links are still working. DirtWorks Designs' Facebook page has most of their mods on MediaFire links. Above, I mentioned that I make mods. Randle Sim Racing, or RSR. At rsrdirtsim.webs.com, rFactor page is https://rsrdirtsim.webs.com/rfactor-downloads . I also have a links page with some rare links, some of which are whole MediaFire libraries used by old rFactor leagues that hastily removed them when moving to iRacing. There's a lot to check out and a lot to still keep it going. Btw, I'm also working on rF2 mods and tracks.

 

[aasasd]

@Daveybird Thanks! I figured out about the tracks' AI being tailored to some cars, but didn't know about specific cars for the AI drivers—thought the Boz Sprints just can't be handled by the game.

 

[Speednut357]

Hello,
What you need to learn about is what we call the AIW file. It is a line the Ai follows around the track and contains information about what speed the Ai should be doing at any particular point. If the Ai is acting weird on any particular track, it is the AIW file that needs to be edited.

You mention training the Ai. This is correct you can have the Ai train itself, and my understanding is that it works well on Dirt ovals. This May be all you need. The Ai will follow the Aiw line and adjust its speed until it has achieved the ideal time for the track. You then find the file the Ai has saved and rename it.

The next level would be to get the software called rF_AIW_CAM_405, which is an AIW line editor. Here is an example of what the AIW file looks like in the editor.

The green Line Is the AI racing line, The red lines are the track boundary, And the dots are the waypoints. This software lets you easily see and fix any errors in the Ai path. It also allows you to fix the pit lane.

 

[aasasd]

@Speednut357 Yea, once I looked out of an AI-driven car and saw it attempting Scandinavian flicks into the turns, it became clear that the behavior is baked into the AI's racing line, and that lighter cars just freak out when doing that.

One thing that's a mystery to me is how some tracks, when used with some late model mod—either DirtWorks or DirtFactor—manage to teach the AI to drift through the turns. Perhaps I just know too little about RF modding (which is definitely true), but I can't quite picture that being done via the AIW lines. I would think that this requires specific support on the game's side.

Bit of a pity that I haven't seen tracks working so well with 321 Bandits, because those little psycho wheeled bucketseats get into corners like nothing else.

 

[Daveybird]

@Speednut357 Yea, once I looked out of an AI-driven car and saw it attempting Scandinavian flicks into the turns, it became clear that the behavior is baked into the AI's racing line, and that lighter cars just freak out when doing that.

One thing that's a mystery to me is how some tracks, when used with some late model mod—either DirtWorks or DirtFactor—manage to teach the AI to drift through the turns. Perhaps I just know too little about RF modding (which is definitely true), but I can't quite picture that being done via the AIW lines. I would think that this requires specific support on the game's side.

Bit of a pity that I haven't seen tracks working so well with 321 Bandits, because those little psycho wheeled bucketseats get into corners like nothing else.

That's because the mods AI grip and stability settings are made for them to powerslide safely, which is hard to pull off. Many of my RSR mods are like that, often a bit less than DWD, but definitely way more than you're describing Bandit Sprints (drove them before, but never bothered with their AI)

 

[MJQT]

@aasasd If you end up being able to get a decent dirt oval experience with AI in rFactor, please share with us! That's a lacking area in the sim racing landscape right now.

I wonder whether the game's AI has any inbuilt understanding of driving on off-road surfaces—or at least provides some for mods. Notably, with the DirtFactor cars, the AI does some drifting even on tracks where Bandit cars drive undeviatingly on the line.

I honestly don't know how off-road surfaces are implemented on rFactor dirt mod tracks. I wonder... is it the gravel surface type with a tuned grip value? It also could be just asphalt with decreased grip, but I doubt it. I don't know, and have never looked into it. Anyway, I bet the AI behaviour will be somewhat related to this.

There also are hidden AI-related parameters in mod files that could control whether AI cars get sideways on the dirt. One that comes to mind is AITorqueStab=(x.xx, x.xx, x.xx), where the values mean "Pitch (car body up/down front/rear), Jaw (car body rotate as when turning), and Roll (car body rotates side to side, as prevented/decreased by anti roll bars)". Defaults are (1,1,1), but I bet you could increase or decrease these values to help cars get sideways Might be worth looking at the values of AITorqueStab in the mods that work better for you.

 

[jgf]

AI in ISI based games often have trouble with any surface other than tarmac; problem seems to be they always use throttle as if on pavement. And there are some car/track/AI combinations where they just seem to be brain dead (I'm currently cursing an Audi A3 mod at the default Anderstorp in GTR2 ...and that's asphalt).

But giving the AI decent setups and then a couple of training sessions at the specific track usually helps, editing the talent files to mellow their cornering may also help. I've read that enabling ABS and traction control for the AI can help immensely, but I don't know how to do that without also affecting my car.

Also, as has been mentioned, if the AIW file was created with a much different car/mod the AI may not be able to cope easily with the car(s) you give them. Or there may just be a bad line at that part of the track. (I'm trying to learn AIW editing for just such problems; I can't even test at Cadwell, in anything from a Formula Ford to a Ferrari, because the AI cannot handle the S curve at the top of the hill, there is a near constant yellow flag there.)

 

[jgf]

... One that comes to mind is AITorqueStab=(x.xx, x.xx, x.xx), where the values mean "Pitch (car body up/down front/rear), Jaw (car body rotate as when turning), and Roll (car body rotates side to side, as prevented/decreased by anti roll bars)". Defaults are (1,1,1), but I bet you could increase or decrease these values to help cars get sideways Might be worth looking at the values of AITorqueStab in the mods that work better for you.

This is essentially an inertia control - how much force will cause that car to deviate from its path longitudinally, laterally, or vertically. Many of the default cars (and many mods) have this much too high, the cars were tanks, you could could hit one hard enough to trash your car while they drove away as if nothing happened. At the other extreme it is entirely too sensitive and will rebound manically from any contact.

The best way to adjust this is a quick single-make test session. You intentionally bump the AI, if you bounce off and they hardly move the setting is too high; if you barely bump them and they fly off track while you barely wobble, the setting is too low. Proper setting is when you and the AI bump, both cars are equally affected. A good rule of thumb is this setting is proportional to the mass of the car; a small, light car like a Formula Vee might be down in the 0.4-0.5 range, while a heavy GT car is typically around 1.5 (I've not encountered anything requiring even 2.0, much less those 2.5-3.5 settings in some default cars).

The vertical setting seems to have little importance in most contacts, but does have an effect if the car gets airborne, such as hitting a bump at high speed, or coming off the top of a hill too fast.

A downside to having "correct" settings is that when hitting TSOs (which for all practical purposes have infinite torque stab) you or the AI may bounce off like a pinball from a bumper. So don't hit TSOs, lol.

 

[aasasd]

If you end up being able to get a decent dirt oval experience with AI in rFactor, please share with us!

So far I'm pretty much adding to a big old spreadsheet of mod × track whenever I'm doing dirt ovals again. DirtFactor and DWD Late Models have it easy because many tracks are tailored to them, and I have to dial the AI strength way back. (Should probably also try other kinds of modifieds—‘big block’ and whatnot.)

Aside from the regular big boys and sprint cars, there's also a mod called DM Kart (the archive)—really, karts for dirt ovals. They are only suited to smallest of ovals, like 1/10 or 1/8 mile, but do pretty well on those, though with the minuscule power they don't drift. I have to set the AI to about 75-80%, and to still have my line and throttle very on point, otherwise the AIs easily beat me. The karts can also be used on paved short ovals, for the asymmetric setups—since regular track karts are rather boring on ovals.

 

[aasasd]

I'm currently cursing an Audi A3 mod at the default Anderstorp in GTR2

Don't SimBin games have their own AI? GTR2 and Race 07 flogged me rather assuredly, but then I migrated to rFactor and had an easier time there. Plus the AIs don't seem to bump the user so much (Race 07 is particularly good in this regard IMO, but that may be a placebo-level difference from GTR2).

 

[aasasd]

This is essentially an inertia control

In every discussion on mod parameters, I keep thinking that it would be nice to have documentation on them compiled into a wiki—so that there would be a ‘final’ source of info on them, and the knowledgeable modders could add the descriptions one by one. Having a wiki or just a repo on Github would be the best bet, probably (and with the sane Markdown notation).

Currently modding docs vaguely seem to be an assortment of Word docs made individually by one guy or another.

 

[MJQT]

In every discussion on mod parameters, I keep thinking that it would be nice to have documentation on them compiled into a wiki—so that there would be a ‘final’ source of info on them, and the knowledgeable modders could add the descriptions one by one. Having a wiki or just a repo on Github would be the best bet, probably (and with the sane Markdown notation).

Currently modding docs vaguely seem to be an assortment of Word docs made individually by one guy or another.

I've thought about the same idea! A simple GitHub Pages website generated from a set of Markdown files. You'd want to document all major isiMotor2 games, though – so IMO basically rFactor 1, SimBin titles (GTR 2 and RACE 07), and Automobilista. And given there's lots of forum posts and Word/PDF documentation floating around, I think you could compile existing knowledge written by experienced modders, without them having to come in and add it themselves.

And you could have one page per game for well-optimized mod and track combinations, including a page or section devoted to dirt oval mods (if any offer a good enough experience).

It's not a project I'm ready to take on yet, but perhaps down the road.

 

[Daveybird]

@MJQT I've collected several notes and findings the past few years, I should post them somewhere, maybe on my site.

 

[MJQT]

Don't SimBin games have their own AI? GTR2 and Race 07 flogged me rather assuredly, but then I migrated to rFactor and had an easier time there. Plus the AIs don't seem to bump the user so much (Race 07 is particularly good in this regard IMO, but that may be a placebo-level difference from GTR2).

SimBin games use an iteration of the usual isiMotor2 AI. SimBin added their own special features (e.g. qualifying versus race speed, rain logic) and changed the range of some parameter values. So it is different but not majorly so. And IIRC there's no oval rules/logic in SimBin titles, whereas there is in rFactor 1. Differences between GTR 2 and RACE 07 may come from code changes, but more likely come down to the optimization of car and track AI-related parameters for particular combinations (e.g. in the vanilla content) – just like you ran into running different cars on the same dirt oval track mods.

 

[Daveybird]

Wow, I've never seen so many people at once on the Internet talk about rFactor Dirt Oval in about 5-6 years!!

 

[MJQT]

Just thought of this thread again after a Discord conversation with Billy Strange, who has tried to work on improving rFactor dirt oval AI in the past (thank you Billy! ). Look at the results 15 minutes into this video, for example.

To summarize and paraphrase the process Billy said he followed back then.

1. First, get the AI to race without crashing into other cars around them. Especially watch out for how they get sideways. Tweak AI brake power and tires. Billy didn't do this, but it would also be beneficial to tweak the AI fast line and corridors.
2. Then tweak the grip levels on the track. There are three grooves on the DWD tracks, each with separate grip levels - for online racing, they're often set to be similar, but for offline, you'd want them to be different. With different grip for different grooves, the AI start "hunting around" for grip, trying different lanes. You'd also want to tweak grip levels per groove on the straights to even things out per lane.
3. Then do the automatic AI learning to help the AI drive better around the track.

If anybody wants to try tweaking (e.g. at Volusia, the track in that video), let us know how it goes. I may give it a try sometime soon, if I feel like it.

 

[jgf]

rfactor AI, like GTR2, is quite adaptable ....but....

since AI is controlled by settings in the track files, in the player file, and in the talent files, it requires tweaking all these (and the interaction between them) to optimize performance to a particular mod. And if this is too far removed from best settings for other mods it is best to have a dedicated install for that mod.