Tips for More Dynamic AI at Road Courses?

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Tips for More Dynamic AI at Road Courses?

Post by kensethfan on Sat Apr 04, 2015 11:13 pm

So I like road course racing in real life, as I imagine most of us do. And it disappoints me that in NR most road course racing is just follow-the-leader style racing. So without going so far as to make entirely new .lps, what can I do to the track.ini to make the AI more competitive? I'm not looking for help with any one road course in particular, just in general.

I imagine decreasing ai_slipcurve might help, albeit it's risky...
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Re: Tips for More Dynamic AI at Road Courses?

Post by fortine_oo on Sun Apr 05, 2015 2:09 am

RC's are prone to "follow-the-leader" racing because it's difficult to pull off a pass against an opponent of more less equal strength, it usually requires a mistake by the lead car. It's not particularly easy to pass an inferior opponent. However, a superior ai will eventually get past an inferior ai, but it can several laps to get it done. A "top tier car" will eventually get around a "2nd tier car", but it usually involves the "2nd tier car" going off line or making a mistake. Remember, ai are not intuitive nor inventive, they are directed to drive by the exe's interpretation of specific guidelines (lp's, track.ini, ai ratings, fast setup, papy_ai.ini) relative to the position of other cars in their vicinity.

Minrace and maxrace lp's play a critical role in RC passing by allowing and/or limiting the ai's alternate racing lines. Not allowing enough space beyond the race.lp will restrict the ai's alternate racing lines, but allowing too much "racing space" can draw the ai off a potential passing line to an "off" line where the ai end up losing momentum and track position. Using knowledge of the racing line and racing tactics is the best way to decide where to put the minrace and maxrace lp's in relation to the race lp; decide how you'd race the space if another car was in your way on the preferred line.

Re:using track.ini values to create more passing opportunities
1) ai_drafting_distance : decreasing this value allows the ai to run closer nose to tail  [ai_dlat_pad (side to side clearance) does have some affect, but using a value 0.8 (or less if it doesn't induce too many incidents ) seems to be enough to not restrict passing]
2) ai_squeeze_pcnt : increase this value (which is 0.0 by default), increase the value only enough to encourage some ai lane changing, 0.05 - 0.50, too large a value can be detrimental to keeping the ai on a preferred racing line (values of 1.0+ can cause the ai to run into walls or completely leave the track)
3) ai_wall_offset : using a value of 20 - 30 will allow the ai to run closer together without causing an accident (20-30 allows some ai to ai morphing but it isn't noticeable at speed)

ai ratings:
1) Driver/Aggression_a minimum value >50, a maximum value of 90-95 will make the ai more prone to attempt a pass, a value 95+ will result in ai attempting a pass even inadvisable situations
2) Driver/RC_a minimum value >50
3) Driver/Consistency_a minimum value >50
4) Vehicle/Aerodynamics_a minimum value >50
5) Vehicle/Chassis_a minimum value >50


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Re: Tips for More Dynamic AI at Road Courses?

Post by Cynon on Thu Apr 09, 2015 7:15 am

ai_dlat_pad is good to play around with if you want to see some unforced AI driver errors. The only thing we're interested in here is that this controls the AI braking zones. Want to see the AI blow corners without much help? Turn this down a bit. Very few if any tracks seem to know what this value actually does, so track makers leave it at a pretty high value and sometimes the racing is crap as a result. Don't worry, though, this can be a negative number. This is why you'll see TMMC drivers make unforced errors at times and have wildly different braking zones from each other.

ai_squeeze_pcnt is a given. Turn this down and they'll run closer to each other side-by-side. Depending on the track and the .lps, different values will have a different effect.

slipcurve behaves more or less like a downforce modifier... the higher it is, the less speed the AI have in the straights but the more they have in the corners. Depending on what you're going for, play with this. Typically I turn this down, the racing is better for it. Turn it too low and you'll get some AI self-spins unless you played with other values in papy.ai. If done right the AI will skate around in the corners a lot.

ai_drafting_distance ... there's no reason not to have it lower than 1.

ai_line_modifier: Yeah, put a semicolon in front of this line and call it a day. I've been doing that fairly regularly for like 4 years.

Now let's go to the papy_ai.ini...

Under [ behavior ]...

crashing_recovery_yaw_velocity is pretty self-explanatory. Put it to around 0.33 and you'll see the AI refuse to spin the car out and try to save the car.

Under [ mechanical ]

There's a nice little field called base_brake_wear that is set to 0.0 by default. It does appear to do something. No I don't need to tell you what. Setting it to 0.08 can't be all bad, though. Very Happy

Now let's take care of pit strategy in the papy.ai file!

driver_fuel_consumption_scaling = 0.2050 ; scales effect of quickness, smoothness, and aggression
driver_tire_break_wear_scaling = 0.10 ; scales effect of smoothness and aggression

...and we're done for now. Depending on if you're doing negative tire wear or not, these can really help.



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Re: Tips for More Dynamic AI at Road Courses?

Post by Mother of Invention on Mon Jun 15, 2015 10:20 pm

Hey I got a question, whats the best way for making poorly rated AI and highly rated AI more spread out. I was looking at one of the PCC Cup races and BurningThunder posted the times, with the good drivers and bad drivers being separated by a good 25 second. How does one go about modifying the AI like this beyond using just ratings?
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Re: Tips for More Dynamic AI at Road Courses?

Post by Syzygy on Mon Jun 15, 2015 11:22 pm

Mother of Invention wrote:Hey I got a question, whats the best way for making poorly rated AI and highly rated AI more spread out. I was looking at one of the PCC Cup races and BurningThunder posted the times, with the good drivers and bad drivers being separated by a good 25 second. How does one go about modifying the AI like this beyond using just ratings?

That's found within the papy_ai.ini file, in the [ driver ] section. Increasing values in that section make the effects of ratings much more noticeable, and you can make specific aspects of the ratings have more sway than others.

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Re: Tips for More Dynamic AI at Road Courses?

Post by Mother of Invention on Tue Jun 16, 2015 6:55 am

thank you man!
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Re: Tips for More Dynamic AI at Road Courses?

Post by NeverNeutral on Tue Jun 16, 2015 8:33 am

You know, with the number of questions being asked about them lately, I think it might be a good idea to make a sticky that details what everything in the track.ini and papy_ai.ini does.
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Re: Tips for More Dynamic AI at Road Courses?

Post by Milan655 on Tue Jun 16, 2015 12:36 pm

There's a very good page with explanations for improving AI with track.ini and papy_ai.ini here: http://www.nrtracks.com/nr2k3/make_ai_adjustments.html
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Re: Tips for More Dynamic AI at Road Courses?

Post by fortine_oo on Tue Jun 16, 2015 5:51 pm

Mother of Invention wrote:Hey I got a question, whats the best way for making poorly rated AI and highly rated AI more spread out. I was looking at one of the PCC Cup races and BurningThunder posted the times, with the good drivers and bad drivers being separated by a good 25 second. How does one go about modifying the AI like this beyond using just ratings?

The spread of the field is due to the ai ratings.
How quickly and to what degree the leader(s) will distance themselves from the rest of the field depends on, 1) the difference in each rating (as applied by the exe) between the competitors, 2) which ai ratings are "less than", e.g. a 10 point difference in Vehicle/Engine is vastly greater than a 10 point difference in Vehicle/Chassis, a 10 point difference in Driver/(TrackType) is vastly greater than a 10 point difference in Driver/Consistency.
Also, the distance and rate at which a "lesser" ai falls behind a race leader is partially track dependent, i.e. the track type, the degree of difficulty due to the track's configuration, and the track length. Obviously, the higher rated ai are going to better handle track conditions and lose less time per lap than an ai that is hobbled by less power, less aero, and less driving ability for a particular track type.

IMO, to modify track.ini values just to create a bigger spread would adversely affect all of the ai and therefore the Player's racing experience.
But, if you are so inclined, you can try:
1) The greater the value for <ai_drafting_distance>, the more difficult it is for ai to stay close and/or to pass, thereby increasing the opportunity to lose time to the leader.
2) Related to ai ratings, track.ini values associated with the ai's grip level [e.g. ai_grip_modifier, ai_inverse_slipcurve_k] or proclivity to drive with more aggression [e.g. ai_squeeze_pcnt, ai_line_modifier] may adversely affect the "lesser" ai more than the leaders, thereby increasing the spread between the leader(s) and the "also-ran"(s).

Everyone's got an opinion  Idea , so FWIW, my experience has indicated that "normal", human-like racing can be accomplished with lp's, track.ini values, ai ratings, and fast setup. Modifying the papy_ai.ini is more prone to cause problems than enhance the racing. (What works on one track doesn't necessarily work on other/all tracks.) Very Happy

-----------------------------------------

Milan655 wrote:There's a very good page with explanations for improving AI with track.ini and papy_ai.ini here: http://www.nrtracks.com/nr2k3/make_ai_adjustments.html


The article (scrap sheet tutorial) that link leads to was information that I had based my (early) ai work on and it was becoming more than I could recall offhand, so I compiled a file that I could refer to when needed.
I never intended for it to be a public release, but Lyndon Karber wished to put it on his website, so I cleaned it up a little and that is what you'll find at the link.

Update:
I have simplified the information, made some additions and corrections, and posted a new tutorial @ ai Development Tutorial - Track.ini Adjustments

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Re: Tips for More Dynamic AI at Road Courses?

Post by kensethfan on Tue Jun 16, 2015 5:58 pm

NeverNeutral wrote:You know, with the number of questions being asked about them lately, I think it might be a good idea to make a sticky that details what everything in the track.ini and papy_ai.ini does.

Yes, please. I realize I've been making a lot of these threads for my AI issues (which I'm still having). I feel like I'm inconveniencing people by making all these threads.
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