Topics

[How long a track tile actually is?]

I'm opening this thread as a spin-off from the "Dissecting" one, so we can post file dissections and gameplay experiments on Stunts physical model in a neat way. It could also be useful as a place for experimental CarBlaster questions. The first results I would like to announce are on a pretty basic but very relevant question that can finally be solved with good accuracy now that we have better insight on CarBlaster workings and the graphic files coordinates:

How long a track tile actually is?

The obvious experiment is to race a car through some distance at constant speed, measure how long does it take and calculate the length accordingly, the "constant speed" bit being the troublesome part: Due to truncation of digital speedometer readings to an integer value and to the nature of the rpm curve (defined in steps of 128rpm) it is very hard to be confident about keeping a constant and known speed value, even with tricks such as holding the gas steadily at redline or lowering aero drag to zero (so that the car rolls on forever at constant speed). Moreover, ideally one would prefer to run this test at very low speeds, so that times and positions can be measured with better precision; however, the speed truncation means the relative error of the speedometer is very high at low speeds (if you assume that a reading of 10mph could be anywhere between 10 and 11, that makes for 10% relative error...). Thus, I ended up doing the most obvious procedure, picking the Lada Niva and shooting it to 245mph in a 27-tile long straight, delimited by water terrain so I could check exactly where the tile boundaries were. The actual speed might be slightly higher than 245mph due to truncation, but at such high speeds the effect on the overall result of a 1mph difference would be rather small.

The results attained were as follows: the Lada took 15.4s to cross the 27 tiles at ~245mph (I was very lucky in that the measurement was unusually accurate, for the nose of the car had almost the same relative position to the start and finish lines when crossing them). Some math reveals that the straight was (assuming exact 245mph speed) 1.048 mile long, and thus each tile would have 0.03882 mile.

And now for the interesting stuff, during which I'll use imperial units so the numbers get prettier. Since one mile is exactly 5280 feet, that means one tile measures 204.95 feet, very close to an integer number... since we should expect a slightly higher speed than 245mph due to truncation, it is perfectly reasonable to admit the developers made it so that each tile has exactly 205 feet, or 62.484 meters. That, in turn, triggers a cascade of interesting implications:

• Using stressed to make experiments with the track tiles, I verified each tile is 1024 points (internal coordinates/stressed units) long (track element graphics are usually slightly longer to generate some overlap and prevent any graphical glitches at the tile junctions). Now, the size of a stressed unit can be found by doing 205/1024 and, surprisingly enough, the result is almost exactly 0.2 feet! (the actual value is 0.2002ft; it would be exact should the tile length be 1025 points, but of course an odd-length tile would not be convenient at all).


• The height of a ramp/hill/etc. is 450 points; using the 205/1024 conversion factor that would amount to 90.09ft, or 27.46m. One might wonder about what Stunts gravity would actually be like expressed into numbers then. Using the fact that a car, when not affected by any weird bugs, takes ~1.45s to drop from a hilltop to the ground, Stunts' gravity acceleration would be 26.1m/s^2, some 2.66 times the real-life value... counter-intuitive, isn't it?


• It is widely known that Stunts cars cannot go faster than 245mph due to game engine restrictions. Converting that speed to internal Stunts units (points per frame) gives 89.83 points/frame. That is, a car running at 245mph covers a distance almost equal to its length in 0.05s (the Indy, for instance, is 98 points long). Now the need for an artificial speed limit in order to avoid excessively jumpy motion at 20 frames per second appears to be perfectly natural...


• And finally: have you ever had the impression that Stunts cars are a bit too large for the tracks they race on? Well, that's not just an impression anymore: Lancia, one of the shortest original cars, is 79 points long, which amounts to 15.8ft or 4.82m, surely much larger than the real car. Larger cars like the Corvette would be well over 6 meters... The reason for those distortions is pretty clear: just like the very tall hills with strong gravity, the game designers have done so because it looks better at low resolutions. And nobody was supposed to notice anyway 

Some nice little things I, and possibly others, were curious about were clarified with those tests. Hopefully the informations can also be useful when people start to design track/scenery elements to scale...

What is it about: since I was willing to exercise my elementary Java skills a bit further, I decided to start a small project and make a new, Java-based, implementation of RPLInfo. While the relevance of coding yet another replay checker is debatable (especially a console based one, as learning how to design decent user interfaces is not on my short-term plans...), what I am really interested in is to use my implementation as back-end for batch file processing, thus creating helper functions useful to competition managers and replay archive organizers. For instance, the first utility I'm working on is a .HIG generator: the program parses the .RPL files, sorts them according to replay times and then print the data into binary .HIG format, using the file name for the pipsqueak name field. I think that would be a cool addition in future replay packs, as well as helping to keep record of race results for the posterity. Other possibilities that can be envisioned include an offline management system for competitions without php sites, which would get aptly-named replay files from a new replays folder, do the proper validity checks (track, car, lap completion), add the new laps to the scoreboard (eventually replacing older laps from the same pipsqueak) and print the updated scoreboard to a .txt . If you can think of other useful stuff that could be added, please do make the suggestions!  I will publish a preliminary version of the code for you to test as soon as it gets a bit more clean and usable.

I have just watched the replays of races 2 to 5 Krys uploaded, and I'm exceedingly surprised by them. There were a number of significant alternate driver decisions, most of the choices being pretty even-matched attempts at finding the ideal line - and that applies even to the centisecond wars... for instance, who would imagine there were no equal routes at all on FTT0105?! That's some great racing, most of all (as Krys likes to say) in a NoRH contest, so I suggest you to treat yourselves comparing all those replays...

Edit: To further reinforce the point, here is analysis for races 2 and 4. Especially in FTT0104, the race was so dynamic it's bewildering...

Well, as Zak mentioned on the news, the bonus percentages are indeed quite strange. The balance between different cars in itself is fine, but overall the percentage values are growing at a rather alarming pace. Not only that makes for a bit strange-looking "compressed" scoreboard, but also having bonuses nearing 50% means that more often than not a pipsqueak will need to improve 0.10s in order to advance 0.05s on the scoreboard, which is quite undesirable and annoying. Since not rounding the corrected lap times to 0.05s precision (i.e, taking times like 0:45.7193...s) or adopting other esoteric manipulations (say, multiplying all times by 1.5 to widen the gaps beyond the 0.05s threshold) feel way too unnatural, I was left wondering whether reducing all percentages to more "sane" values would be a good idea, and it seems indeed to be the case.

The most natural procedure for bonus renormalization would be to reduce all percentages so that if two times achieved with different cars were equivalent before the changes they remain equivalent after them, save for rounding differences. Let's consider percentages for two arbitrary cars a and b, Pa and Pb, which we want to modify so that Pa becomes (presumably smaller) Pa' and Pb is corrected accordingly to Pb' so that equivalent times obtained with the old percentages remain equivalent with the new ones. A bit of math leads to an expression for Pb':

Pb' = 1 - (1-Pa')*(1-Pb)/(1-Pa)
(note percentages are expressed as decimals - i.e., 0.38 and not 38%)

I tested the above expression with the percentages of Z86. The Carrera percentage was used as the reference value Pa, which I arbitrarily reduced from 0.42 to Pa' = 0.32. The resulting percentages were:

Code Select Expand


Car Curr. % New % New %, rounded
Acura 0.38 0.273 0.27
Audi 0.33 0.214 0.21
ZR1 0.33 0.214 0.21
GTO 0.36 0.250 0.25
Jaguar 0.16 0.015 0.02
Count. 0.39 0.285 0.28
LM002 0.39 0.285 0.28
Lancia 0.28 0.156 0.16
P962 0.14 -0.008 -0.01
Carrera 0.42 0.320 0.32
Indy -0.14 -0.337 -0.34



The renormalization brought the larger percentage values to levels comparable to the ones at Z80. Of course, all the differences accumulated reflect on the lower values, culminating with the quasi-surreal -34% for Indy (unlike the Acura/Countach/LM002 soaring percentages we have now, this wouldn't be likely to get any lower, however). Moreover, the absolute differences between the values also were raised somewhat from the original set, since a difference of 0.02 in percentage when one is to correct times by a ~0.9 factor (~10% bonus) range is much less significant than 0.02 with ~0.5 factors (~50% bonus).

In order to see what would actually happen to the results, here's an example using times from the current skirmish between me and CTG on Z86:

Code Select Expand


Car Time Corrected by curr.% Corrected by new% Corrected by new, rounded%
Countach 01:14.95 45.72 53.59 53.96
Carrera 01:18.80 45.70 53.58 53.58



The first "Corrected by new%" column was calculated with percentages rounded to three digits, while the second one had the percentages truncated to two digits. With three-digit percentages the results are virtually equivalent. Truncating at two digits introduces some distortion (four tenths...), but this is a rather extreme case anyway (Countach percentage would be 28.48%, which is quite different from 28%), and since there was already a similar rounding before this truncation isn't a really serious issue.

There is, however, another non-obvious change induced by renormalization. As discussed before, absolute changes in percentages are more significant with large bonuses than with smaller ones. That means the catchup between cars from one round to another will be slowed down. Consider, for instance, a scenario where Carrera does 1-2-3 in Z86 and Indy gets unused. With current percentages, Z87 bonuses would be 32% (-10%) and -11% (+3%). Now, in Z86, a 1:15 Carrera lap (corrected time 43.50) would be matched by a 0:38.16 Indy lap. After the bonus updates in Z87, 1:15 with Carrera would mean 0:51.00 corrected time, which would be matched by 0:45.95 with Indy. Had we employed renormalized percentages on Z86, the percentages would be 32% and -34% for Z86, and 22% and -31% on Z87. Taking again a 1:15 lap with Carrera as reference, it would be matched by 0:38.06 on Indy at Z86, of course equivalent to the original situation except for rounding errors. On Z87, however, the equivalent Indy time would drop to 0:44.66 - a 1.3s change from the previous scenario.

Summarizing, renormalization would result in saner percentages with a bit extra tampering of balance and somewhat slowed down recovery of low percentage cars. Still, I think the gains outweigh any possible losses, and thus I actively suggest Zak renormalization of bonuses for Z87. So, your opinions?  

Well folks, lately I reflected a bit about the various World Ranking schemes we had been using lately. While it may be not a priority topic at this moment, even because most possible managers are too busy right now, it might be useful to have some discussions already so that when the time for reviving the rankings comes (maybe on time for the possible next editions of USL, ISM or similar special events?) our ideas are clearer.

The main issue I want to put up is related to the different kinds of contests we have. It seems by the time SWR was being consolidated you guys had a few debates on whether IRC or NoRH contests should be included on the ranking. Well, back on the start of 2007 there were six regular full-season contests: ZakStunts, USC and SDR-RH (monthly races, free rules), Kalpen (6-week races, free rules, Indy only), WSC (monthly races, IRC rules, Indy only) and SDR-NoRH (monthly races, NoRH). Eventually, it was decided that NoRH was different enough from RH racing to justify the non-inclusion of SDR-NoRH in SWR, while WSC was included despite the IRC restrictions. By that time, WRL included only the three free-rules monthly contests, deeming Kalpen as too irregular and WSC as not "strong" enough.

One year later, however, the situation changed a lot: ZakStunts is the only active contest with regular rules. The other contests are WSC, FTT (3-week races, NoRH) and JACStunts (weekly races, ISA and NoRH). In addition, WSC has eventually grown into a significantly "stronger" contest after all the hardships of 2007. All of the four contests differ very significantly not only in terms of rules but also on the duration of the races. And in my view there would be no option to an organizer but to include at least WSC and FTT beside ZakStunts in a world ranking circa 2008. So the question becomes how to manage the differences... solving issues such as:

• Do we really need to make adjustments for "comparing" RH and NoRH within a ranking?
• Should 3-week races be weighed down in relation to full-month races?
• Is there a reasonable way to account for very short races, or even special event results?

My initial answers to those would be No, Yes (but not by the whole 25% though) and (probably) Yes. But those are not exactly simple decisions, so the more arguments we throw in, the better...

Comments, everybody... 

BJ made a quite interesting track... it has a definite SDR feel, which makes me like it even further  All the twists and bug corners should produce  a variety of different choices in terms of driving lines. As for the winning car, I'd say P962, but I'm not 100% sure of that...

Have you guys noticed we had a sudden increase in the number of visitors in the last few weeks? When I glance at the bottom of the screen I usually see at least 15 guests, often 20 or even 30...

[Campeonato Brasileiro JAC de Stunts]

Earlier this week a couple exchanges in Portuguese between me and Dark Chaser in ZakStunts news intrigued some of you... basically, he was inviting me to the Campeonato Brasileiro JAC de Stunts, a most interesting contest started early this year but already in its second season (!). In case anyone is curious, relevant debates - in Portuguese - and updates are done at this Orkut community, while there's a largely secondary webpage at http://regismuller.googlepages.com/stunts .

The rules are very sui generis: the current season is composed by 18 (!) weekly races, using a relatively diverse pool of cars. Races are BOTH ISA and NoRH - NoRH is trust-based, and before CTG argues something: the obnoxious "RH wars" nearly started this week, but the final decision was to keep current state of affairs for the best. Number of competitors vary form 8 to 12, with currently the main victory aspirants being pipsqueak-manager Thiago Marques (winner of the inaugural mini-season) and Alexandre Ramos AKA Dark Chaser.

As for the current race, we're in Round 3, which deadline is tomorrow midnight plus a 12-hour tolerance. The track is a damned long (~2:30 !!) Indy powergear blastout I'm not having much luck with (screenshot attached below). Next week track seems to be an unusual proposition - a Countach handling challenge... Those two and all other tracks are already available for your inspection and scrutinity at http://regismuller.googlepages.com/pistas ...

Edit, 03-08-2008: Although the Orkut community remains the same, the old website is no more. Head to http://jacstunts.ueuo.com instead (or just follow the Portal link). Also, the thread title was modified...

[Nissan Skyline R32 GT-R]

Edit: The first release of this car is already available, at the new cars for 2009 topic.

A couple days ago, there was a small discussion at the "Special Cars in 2008" ZakStunts thread around some comments by Argammon. Although I may have reacted rather badly at the time to those comments, they motivated me to kickstart another tuning project which was lying in my head for a while: coding a new, real car with accurately modeled performance. The chosen vehicle, as you guessed from the title, is the legendary Nissan Skyline R32 GT-R. Reasons for selecting that particular car are various; including, first and foremost, that I am a die-hard Gran Turismo old-schooler  Implied of course is the fact that Gran Turismo 2 is a pretty viable testing plattform... but it goes beyond that. On its era, the R32 GT-R was among the very best, and most advanced, cars of the world. And it is very realistic to think of it as a possible Stunts car, for its release was on 1989! Finally, the Stunts GT-R will be a "slow" custom car with realistic handling and performance, traits not seen so often as vehemently pointed out by Argammon.

Currently, the new car is in alpha-stage development. The difficult part, torque curve and gear ratios, is already finished. Handling still requires some testing, but the intent is to make it moderately above average taking NSX, Carrera and etc. as reference. More details will come when the car is ready for release, but before that I kindly ask your opinion about aesthetics... the dashboard is more or less settled for NSX, since it has a somewhat similar layout to the real thing (see pic below). The real problem is the 3D shape: all options aren't good at all and I can't decide which one is less bad... So, please vote on the poll above. If you don't remember how does a R32 Skyline look, check the pics below. Thanks and see you soon!
 

[LWT-ZR1 GT3 Mark II]

(original subject was "GT3 Mark II is released!". The version of the car on this first post is outdated, scroll down to here to find a newer one with updated graphics)

Here it is, the LWT-ZR1 GT3 Mark II, an updated version of the non-IMSA race car... The novelties are listed below:

• First of all, Chulk's proposed rechristening as Vette GT3 or GT3 MkII is now recognised as official nicknames   
• Most important change: The old Corvette-derived V8 has given place to a modern V10, licensed and lifted straight from the BMW M5... The new torque curve is shifted about 1000rpm to the right, resulting in much better sync with the 6-speed gearbox. A side effect is the GT3 is now quite a bit faster (about 3 seconds on Default short-way), but nevertheless it is still beaten on straights by IMSA cars.
• Gear ratios were slightly tuned in order to take the most advantage of the new torque curve (1st to 4th are somewhat shorter, 6th is a tad longer)
• Car mass was raised a bit as well, in order to curb performance levels (regulament issues, you know...)
• Brake effectiveness had a small improvement as well, allowing for a tiny bit more aggresivity. Note that car adhesion remains unchanged, however...
• And last, but not least: accurate analog speedometer and rev meters.

Although the GT3 has gotten through beta stage, feedback is still very appreciated! 

I dont' know whether anyone was already working on something similar, but over the last weeks I have been completing and organizing the archive of tracks and winning replays on my Stunts folder with the races from Aug '05 on. Aside from a few significant omissions, which I'll confirm later on, I could find nearly everything on the net. Thus, if Zak or somebody else is interested - e.g. for the projects being discussing lately - just ask...

Edit - topic title modified in 2012/01/19; original was Competition Archive II: The Later Years
Edit 2 - topic title modified in 2021/02/19; original was Replay hunting & Competition Archive updates. Also merged the Competition Archive 2019 topic into this one.

So we can give Zak our feedback...
As for me, everything looks nice, clear and simple. My only suggestion for now, which is completely unrelated to the new stuff anyway, is to make some secondary colours on pipsqueaks' profiles (like on borders or textbox foreground/backgrounds) customizable, so that we could, for instance, apply team colours on them. Also, will data on Car Bonuses for older tracks be stored on "Car Bonuses" pages, or in the old scoreboards themselves?

(Zak, please move the topic elsewhere shouldn't this be quite the right place)

Well, title says it really. Wishing to try True-DOS Stunts again without leaving the convenience of Windows (and video capture  ), I did some research and figured out a way. The procedure is somewhat involved, and requires a couple auxiliary programs - namely, in order to use an image floppy disk to boot DOS on DOSBox and an small image HD containing the Stunts installation. Fortunately, nearly all the annoying stuff needs to be done just once. I will post a step-by-steb as soon as I get to test some technicalities. However, the real question is: does this "double-emulation" scheme suceed to run authentic Stunts? Although I did notice some improvement on handling as you guys describe, I do not trust my judgement entirely, for I do not play under True-DOS since childhood... so, would any of the more experienced folks give it a try and tell us the results? Thanks in advance...

Since I discovered, just after joining the community, that VDMSound stole 10% of Stunts' speed in my PC for quite a few years, I've been wondering about ways to make usage of Stunts setting up and usage in a modern machine as simple and unobtrusive as possible, and how much of help it could be to potential newcomers. A  very simple idea would be to pick a Stunts folder, then grab DOSBox and some good frontend and wrap everything into a neat Nullsoft Installer (nsis.sourceforge.net). Yesterday I was able to give the concept a try, and produced a crude, very ad hoc installer, comprising ZakStunts non-boot CD package and DBGL frontend 0.60RC2 (taken from http://home.quicknet.nl/qn/prive/blankendaalr/dbgl), which conveniently already comes with DOSBox 0.71 integrated (all I had to add were the movie codecs for SDR-like stuff).

Being an image worth a thousand words, below are some attached screenshots. Discuss at will, and PM me if you have interest on seeing the test version live (webmasters welcome!) ...

Hi folks; as a newly registered member I feel proper to make some cute introduction post... I first played Stunts somewhere between late '95 and early '96, as a 7-year old kid; it probably was my second or third PC game ever. Since then, I have been racing for at least a couple months every year - there is no game with such replay value, period - , and over the years I got to slowly unveil more and more nifty tricks on this deceptive simplicity which is Stunts. So I found now a proper, if only a tad late, moment to join the community. The next logical step would be entering some competition, and indeed I intend, for now, to race Kalpen keeping a relaxed semi-amateur profile. As you will realize, I'm not a very prolific poster - I rather sit and watch people biting their heads off ;-) -, but I'll be hanging around... so, see you around, fellows.