Stunts Forum

Stunts - the Game => Car creation with Stressed => Topic started by: Overdrijf on October 19, 2018, 06:44:28 PM

Title: Stunts goes Dtm
Post by: Overdrijf on October 19, 2018, 06:44:28 PM
EDIT Januari 8th 2019: I made a slightly improved version. The updated version is in the DTM 1.1.zip, the old version in DTM 1.0.zip. Behavior is exactly the same, it's just minor graphics and text fixes. Post #24 contains a bit more info about the update.



That's right, I am at it again. Coming in with not one, not two, but three new cars: the Stunts DTM pack. The Deutsche Tourenwagen Meisterschaft is coming your way. Bam.

(https://i.postimg.cc/C5z0zKWm/DTM-group-portrait.jpg)

A rivalry for the ages comes to Stunts. An Audi, a Mercedes and a BMW will battle it out. These beauty's are modeled and named after the cars from the 1990-1992 era, when these brands first crossed paths in the German touring car circus, but their performance has a little 2012-2018 era mixed in, as well as a healthy dose of "this way it's more fun". They come fully loaded for high speed racing around dynamic tracks, with the crowd favorite 5-speed gearbox and carefully tuned performance.

So they're fast, and they're fun, but one car could have done that. The point of this pack is how close these three are in performance, with a shared identity but a little flavor of their own as well. They can be raced against each other in a single race, in an IMSA Cup style format (who knows, one day) or, and this is the cool part, under a single coefficient in Zakstunts. Three cars for the price of one, races with four or five eligible cars in total. On most tracks the difference between optimized laps with all three vehicles should be less than half a second per minute of race time. So do you try to find how to get that small bonus, or do you count on the one you feel best with to take you home?

So, here are the specs (tested on BB 1.1):

BMW M3 E30 DTM:
Engine specs: DOHC inline 4, 2300cc
Torque peak at: 8100 rpm
Max horsepower: 370 HP
Transmission: 5-speed
0-60mph: 3.15s
0-100mph: 7.30s
Half mile: 17.50s
Flat track top speed: 186 mph
Real top speed: 199 mph
Strong suits: High speed acceleration, handling feedback, top speed, bugs, sharpest automatic gears

Mercedes-Benz 190 E DTM:
Engine specs: DOHC inline 4, 2500cc
Torque peak at: 8100 rpm
Max horsepower: 392 HP
Transmission: 5-speed
0-60mph: 3.15s
0-100mph: 7.30s
Half mile: 17.45s
Flat track top speed: 188 mph
Real top speed: 196 mph
Strong suits: Mid speed acceleration, handling, overshifting, smoothest automatic gears

Audi V8 quattro DTM:
Engine specs: DOHC V8, 3600cc
Torque peak at: 8100 rpm
Max horsepower: 474 HP
Transmission: 5-speed
0-60mph: 3.15s
0-100mph: 7.40s
Half mile: 17.60s
Flat track top speed: 190 mph
Real top speed: 197 mph
Strong suits: Very high speed acceleration, flat track top speed, jump distance.

The cars are in the attachment. I look forward to hearing what you think of it. Jetzt geht's los!

Note 1: This post was brought to you with the help of Duplode being awesome, and giving me advice, mostly on shape design with Stressed. The cars wouldn't have looked like this without him. The tools I used are Car Blaster by Mark Nailwood, Stressed by Dstien, a little bit of Anim8or and my trusty GIMP for image work.

Note 2: I redid a lot of things a lot of times, so it took quite some time to get to the end result. This did result into me getting some insights into the physics of Stunts, things that may or may not be known already to some people. I will share these insights in the appropriate thread somewhere in the coming weeks, with demonstration cars.

Note 3: I don't have names in mind for all the paint schemes, but #9 on the quattro is definitely called the Proudi.
Title: Re: Stunts goes Dtm
Post by: dreadnaut on October 21, 2018, 06:04:40 PM
New cars! :o :o :o  And I'm quite impressed by those front grills!

I'll have some time tomorrow and I'll try them out. The three-side race sounds perfect for R4K, if Cas is interested.
Title: Re: Stunts goes Dtm
Post by: Overdrijf on October 21, 2018, 09:57:59 PM
New cars! :o :o :o  And I'm quite impressed by those front grills!
Thanks. Going over reference pictures I quickly felt that was a part I could not ignore. I'm actually not all that much of a car person outside of Stunts (my secret, it has been exposed!), but since doing this I insta-recognize these brands everywhere. Thanks to Duplode the cars now actually look like this ingame (the picture up there is composited of course, but nothing has been touched up) rather than just in Stressed.

Quote
I'll have some time tomorrow and I'll try them out.
:D

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The three-side race sounds perfect for R4K, if Cas is interested.
Certainly, especially since Cas was planning on using a lot of custom cars this season. I'm already looking forward to it. Although to be fair he just did a car designed by me, he just did a short car, a high grip car and a fast accelerating car, all of which these cars are as well, to some degree. ;D

Overall, since I'm making the comparison now anyway, I'd say these three are more balanced, more thought out and suited for more tracks than the more specialized kart.

I'm also curious what people will think about the internal differences in how these cars feel. It's subtle, but the Audi does feel calmer and more IMSA-like in handling to me compared to the more pocket rocket like BMW.

I hope these will put as much of a smile on your face as the looks of the latest Zakstunts track did on mine.
Title: Re: Stunts goes Dtm
Post by: Duplode on October 23, 2018, 07:48:32 AM
The DTM set is now available from Southern Cross (http://scr.stunts.hu/mods.html#custom-cars)  :)
Title: Re: Stunts goes Dtm
Post by: Cas on October 24, 2018, 08:59:20 PM
Sorry guys that I did not reply quickly on this one. It certainly is a great idea to try this car set in R4K :)  I still have to create a comfortable way for the cars to be downloaded if they're custom made, from the R4K site. I'd like a "download car for current race" button or something like that, but as simple as it sounds, there are some catches. Of course, the cars are already here and in Southern Cross and I can host them too. I just would like for the "access" to them from R4K to be more direct and "elegant" at the same time, ha, ha.

As I was telling Overdrijf via PM, my idea is that the next race should go from the 1st to the 25th of November and, from now on, all races be 1st -to-25th of each month. So this season would have only these three races. For the next season, I'll try to have a more robust system ready, so that, for example, season results can be calculated. As usual, I have many "half-ideas" that I hope to make full by the end of the year.
Title: Re: Stunts goes Dtm
Post by: Overdrijf on October 27, 2018, 04:55:40 PM
We're ready to go on November 1st. ;D

I'm already curious what kind of section times the different cars will get. After the racing I get to do the analyzing.
Title: Re: Stunts goes Dtm
Post by: Overdrijf on October 31, 2018, 09:07:12 AM
What has a monocle but no speed limit?

Die Ottobahn! (http://dimioca.com/r4k/index.php?o=race)

(https://i.postimg.cc/2SmMX1Zm/DTM.png)

(Track available now, scoreboard opens tonight.)
Title: Re: Stunts goes Dtm
Post by: Cas on November 01, 2018, 02:29:02 AM
It's open now! :)  This will be the first multi-car race in R4K. Let's see how it works out. I found a couple of bugs in the website as a result of the track update, which I expected. Now they're fixed.
Title: Re: Stunts goes Dtm
Post by: dreadnaut on November 01, 2018, 03:21:11 PM
What has a monocle but no speed limit?

Oh, that is brilliant! I'm busy for the next week or so, but I'll defenitely race on this one, and try all the cars!
Title: Re: Stunts goes Dtm
Post by: Duplode on November 12, 2018, 03:17:17 AM
Trying out the Mercedes on Die Ottobahn, I noticed the colour of the steering wheel dot. was changed. I wasn't aware that was possible (and I somehow hadn't noticed the Kart used that effect as well). How did you do it?  :)

(By the way, I encourage you all to give it a go there. These cars are a blast!)
Title: Re: Stunts goes Dtm
Post by: Overdrijf on November 12, 2018, 10:57:37 AM
Trying out the Mercedes on Die Ottobahn, I noticed the colour of the steering wheel dot. was changed. I wasn't aware that was possible (and I somehow hadn't noticed the Kart used that effect as well). How did you do it?  :)

(By the way, I encourage you all to give it a go there. These cars are a blast!)

That's in the STDB[NAME].vsh file, together with the gearbox knob. You can change the color and the shape by altering dot and dota, the mask. I'm not sure if you have to change dot1 and dot2 as well, which are some sort of small palette files with the dot inserted in the background. I did change the dot in the background to match the new one, just to be on the safe side.

If you want to make the dot a bit bigger, like I did, you'll (of course) also need to resize the image to some size you know the mystery bites for (the stuff you see below width, height, X and Y when looking at this in Stressed, for the uninitiated). I think I got these of a gearbox, or maybe an ins2. It seems to work quite well, the invisible parts of the image don't seem to interfere with anything.
Title: Re: Stunts goes Dtm
Post by: Duplode on November 12, 2018, 01:07:50 PM
Oh yes, dot and dota -- I had forgotten about those. Perhaps I should try and make a new car to get a refresher on things :) The mystery bytes detail is also interesting, thanks.

Title: Re: Stunts goes Dtm
Post by: Overdrijf on November 12, 2018, 04:44:05 PM
Perhaps I should try and make a new car to get a refresher on things :)

Yeah, you probably should. Totally for your own good, not at all because I want more new cars. 8)
Title: Re: Stunts goes Dtm
Post by: zaqrack on November 13, 2018, 12:06:43 PM
Astonishing work (and track) here, pipsqueaks :)
Title: Re: Stunts goes Dtm
Post by: Overdrijf on November 13, 2018, 06:21:02 PM
Thanks. That means a lot, coming from someone with as large a track collection as yours.



I think I just figured out why the front wheels of the BMW are sometimes slowly moving to the left of the vehicle on long playing sessions (an issue that didn't become visible until going for the same NoRH lap over and over again): there's some coordinates slightly off in the wheels, must have happened in the final bottom plate fixes.

It's hardly a fatal bug, but it's now the first item on the list of things to fix in a potential version 1.1.  :-\
Title: Re: Stunts goes Dtm
Post by: Overdrijf on November 26, 2018, 06:21:02 PM
Demmm.

Only now, after a month of Race for Kicks, copying the scoreboard to save it, I notice I called the M3 the M30.

That's it, I'm doing a version 1.1. And I'm doing it before Dreadnaut has a chance to select the "M30" for next year.
Title: Re: Stunts goes Dtm
Post by: dreadnaut on November 27, 2018, 08:19:37 PM
That's it, I'm doing a version 1.1. And I'm doing it before Dreadnaut has a chance to select the "M30" for next year.

Oh, M3 doesn't sound fast enough, we'll use the Audi then :P
Title: Re: Stunts goes Dtm
Post by: Cas on November 28, 2018, 09:02:25 PM
Man, after this time on the community, I should have at least one car of my own design. I've never sat to analyse exactly what each thing does. The 3D design, I already understand. It's still a lot of work to do, but I can see how it's done. It's the car functioning that gets me confused... mostly. I'll be taking a deep read in the Wiki. Is there any important thing that I need to know about creating my own car that are not there?  I figure I should also read this subforum thoroughly!  Where to start! XD
Title: Re: Stunts goes Dtm
Post by: Overdrijf on November 29, 2018, 09:16:58 AM
I think there's a few small holes in the wiki, but I couldn't really point them out. It's mostly in the 3D model stuff I think, the description of how the coordinates of a wheel work is for instance wrong, as far as I can tell. RES-file wise I've also got some maybe new insights in length and handling I've yet to post. I'll get around to that one of these days.

Most of the .RES stuff is actually pretty straightforward. Torque curve interacts only with gear ratio's, mass and air resistance. If you scale all of them to exactly twice their value you've got the exact same car (assuming the mass falls into the same power gear category.) The handling number interacts with car length (not sure about width) and surface grip modifiers. These actually don't scale the same way, which is what I need to post about, a short car with low handling number is different from a long car with a high handling number. But because speed and cornering are separated systems you're not going to screw up your cornering by working on your speed curve or the other way around.

The torque curve itself has some weird features, it's hard to design to an exact top speed, and if the curve goes down too fast at the end you open it up to slowdowns where you would expect speedups. But you'll notice that happening as you mod and test.
Title: Re: Stunts goes Dtm
Post by: Duplode on November 30, 2018, 05:02:26 AM
After racing with the three cars, I can confirm each of them has its own distinctive temperament. The Audi is smooth as butter, IMSA like as you say, and definitely the easiest of the three. The BMW is very nimble, and I'm fairly sure it beats the other two on a twisty track. All the responsiveness, however, means you end up being very close to the limit at all times. Another complication is the occasional curveball thrown by the bug-susceptible nature of the car. To me, the BMW is the most challenging of the set. Lastly, the Mercedes feels more like a typical "slow car", and is probably the one for which the conventional driving techniques translate more easily.



I think there's a few small holes in the wiki, but I couldn't really point them out. It's mostly in the 3D model stuff I think, the description of how the coordinates of a wheel work is for instance wrong, as far as I can tell. RES-file wise I've also got some maybe new insights in length and handling I've yet to post. I'll get around to that one of these days.

Looking forward to it  :)

The torque curve itself has some weird features, it's hard to design to an exact top speed [...]

Do you mean flat track top speed, or real top speed, or both?



One tiny issue I noticed is that the stripes over the hood from the BMW's paint job #9 flicker a lot. I'm not sure about what, if anything, can be done about it (I don't see anything obviously problematic when looking at the model on Stressed, though I didn't actually attempt tweaking it yet).

Title: Re: Stunts goes Dtm
Post by: Overdrijf on November 30, 2018, 02:02:55 PM
After racing with the three cars, I can confirm each of them has its own distinctive temperament. The Audi is smooth as butter, IMSA like as you say, and definitely the easiest of the three. The BMW is very nimble, and I'm fairly sure it beats the other two on a twisty track. All the responsiveness, however, means you end up being very close to the limit at all times. Another complication is the occasional curveball thrown by the bug-susceptible nature of the car. To me, the BMW is the most challenging of the set. Lastly, the Mercedes feels more like a typical "slow car", and is probably the one for which the conventional driving techniques translate more easily.

Thanks, good to hear feedback like that.

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I think there's a few small holes in the wiki, but I couldn't really point them out. It's mostly in the 3D model stuff I think, the description of how the coordinates of a wheel work is for instance wrong, as far as I can tell. RES-file wise I've also got some maybe new insights in length and handling I've yet to post. I'll get around to that one of these days.

Looking forward to it  :)

I need to write a proper post with exact numbers and add the example cars so people can try it for themselves. The gist of it was this: I got two cars with the same handling/length, but one twice as long as the other. The short one steers a lot faster, more responsive. I figure it's related to the reason longer cars jump farther: When a Stunts car turns it doesn't turn by a certain number of degrees per 0.05 seconds, it turns by a certain distance per 0.05 seconds. For a shorter car the front end moving the same distance means it turning a larger angle, so it steers more quickly. The handling parameter seems to be in control more of how long you can keep cornering before the car starts slipping. So they still counteract each other, if you corner slower but can keep it up longer you can corner sort of around the same distance at the same speed.

I think...

Because this is where it gets a little weirder. All of the faster cars can do a single wide corner at around 150 miles an hour, despite their length or exact handling parameter. The superkart does it, the IMSA cars do it, the Indy does it. It's some sort of ceiling, a limit to cornering ability similar to the limit there is to top speed. I found this limit, or the general area of it, for a test version of the Mercedes. And that's where something weird happened. I had four versions of the car. The one with the lowest handling parameter was the slowest around a lap, by a small margin, but it felt quite good to drive. You had some room for error. The three versions above it had roughly the same lap times, but I think it was the second slowest one that usually took more tries than the others not to spin out. When you spun, you spun, no coming back from it. The car was more on edge. When the handling parameter rose further this behavior went away again. I dubbed this place "the sour spot", and I tried to use it on the DTM cars by putting all of them just below that spot. The idea is that the car with the least amount of handling gives the most warning when something is about to go wrong, creating a balance between where the edge of the car's ability is and how well a human driver can stick to that edge. The concept does not completely match your description above though. The BMW has the lowest handling and even the lowest handling/length while being the shortest. To me it feels short and responsive, maybe a little too much so, but I also get pretty good feedback, which is probably part of the reason I did my fastest NoRH lap with it. It sits the furthest from most other cars in feeling due to being so short, but that was less of an obstacle for me after all the testing I did with these. The Mercedes and the Audi have the same handling/length, so the longer Audi has the best handling stat, but it feels a little slower and smoother steering-wise than the others. The Audi to me also feels a little closer to the sour spot, it handles quite well, but I have trouble finding the edge before crossing it. I made quite a few NoRH attempts with that one.

My experience was probably tainted by the design ideas I tried to implement though. There's probably some wishful thinking involved.

That's basically it. I have no idea if the sour spot is even available for all lengths of car, or that it's a artifact of a specific unlucky combination, but I definitely feel like there's a limit to how much handling a car can handle before more handling stops doing it any good. The superkart for instance is massively over-handlinged. It would drive just as well with maybe as little as half its number or more. Have to look the proper number up to make a better estimate.

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The torque curve itself has some weird features, it's hard to design to an exact top speed [...]

Do you mean flat track top speed, or real top speed, or both?

The combination, kind of. The BMW has a slightly lower max rpm than the other two with the same top gear ratio, yet I could not for the life of me get its real top speed (the highest of the tree) down just one or two mph, at the very least not without altering the air drag. I could give it slowdowns or lower its flat track top speed, but I think I could only lower that by 2 mph, not one. I think one of the things that's happening is that because the game works in discrete intervals of 0.05 seconds you don't actually touch every bar in the torque curve. You often end up skipping a bunch. That's also what causes the slowdowns I figure. You skip ahead to an rpm that has a really low power (just 2 ticks or so) the game makes its new calculations with that very low torque and drops you down quite a few rpm's on the next time step. But the problem with the top speeds is that it's not one or two bars that decide a particular top speed, just the ones that don't have enough power to speed up any further. If the bars lower on the curve are too high you can skip right over those two. High air drag helps, it makes the high speed behavior of a car more predictable, and a power curve that slopes down over a longer way, giving it a big gap between flat track and real top speed, probably helps as well in that regard. Or you should just not care too much about specific numbers and exact balance.

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One tiny issue I noticed is that the stripes over the hood from the BMW's paint job #9 flicker a lot. I'm not sure about what, if anything, can be done about it (I don't see anything obviously problematic when looking at the model on Stressed, though I didn't actually attempt tweaking it yet).

I had some problems with that earlier. I didn't pay a lot of attention to it post release, but I'll happily believe it. I'm not sure what can be done either. I think part of the story was interference from the wheels and the sort of wheel houses. Since the BMW has the lowest hood it's the easiest to interfere with. The final form those wheelhouses take is pretty trimmed down but I also didn't want to leave them out completely.
Title: Re: Stunts goes Dtm
Post by: Duplode on November 30, 2018, 09:28:09 PM
I got two cars with the same handling/length, but one twice as long as the other. The short one steers a lot faster, more responsive. I figure it's related to the reason longer cars jump farther: When a Stunts car turns it doesn't turn by a certain number of degrees per 0.05 seconds, it turns by a certain distance per 0.05 seconds. For a shorter car the front end moving the same distance means it turning a larger angle, so it steers more quickly.

Car length does have a major effect on responsiveness, and as you say it is indeed related to jump distances. If I remember correctly, it goes like this: the game calculates displacements for each of the four wheels, and then, roughly speaking, averages them to compute the overall position of the car. Steering is actually done by changing an angle, but that angle is the direction on which the front wheels are moving. For a longer car, the same change of direction of the front wheels has less of an effect on the car as a whole over a  time step.

The handling parameter seems to be in control more of how long you can keep cornering before the car starts slipping. So they still counteract each other, if you corner slower but can keep it up longer you can corner sort of around the same distance at the same speed.

That is the right intuition. The handling/grip parameter tells you how hard you can steer (i.e. how large the steering angle of the front wheels can get) at a certain speed before skidding or losing control. I had found the exact formula for that, but I lost my notes about it in my HD crash in '16 (http://forum.stunts.hu/index.php?topic=3355.0). In any case, longer cars require harder steering for changing the direction of the car at the same rate, so they can't take corners as fast.

All of the faster cars can do a single wide corner at around 150 miles an hour, despite their length or exact handling parameter.

Not quite. The limit speed of IMSA cars following the ideal line on large corners is slightly above 170mph; for the Indy, it is somewhere around 190mph. Such speeds are, as one might expect, very hard to attain without RH.

The sour spot theory is very interesting, and deserves further investigation. I feel it might also have something to do with steering responsiveness (i.e. how the car responds to steering input by the driver).

The BMW has a slightly lower max rpm than the other two with the same top gear ratio, yet I could not for the life of me get its real top speed (the highest of the tree) down just one or two mph, at the very least not without altering the air drag. I could give it slowdowns or lower its flat track top speed, but I think I could only lower that by 2 mph, not one. I think one of the things that's happening is that because the game works in discrete intervals of 0.05 seconds you don't actually touch every bar in the torque curve. You often end up skipping a bunch.

Besides that, the torque curve is made of segments which are 128RPM wide. If you set the redline at 8192RPM, there will be 40 segments; if the ratio of the top gear is set so that the real top speed is 200mph, the resolution of the real top speed will be 5mph per step, which is indeed quite coarse.
Title: Re: Stunts goes Dtm
Post by: herbert3000 on December 27, 2018, 01:02:58 AM
Thanks for the DTM pack, Overdrijf!
Really appreciate it!  :)

It really pays off that I visit the Stunts Forum every now and then!  ;D
Thank you all and a Happy New Year 2019!
Title: Re: Stunts goes Dtm
Post by: Overdrijf on December 31, 2018, 12:56:14 PM
Thanks for the DTM pack, Overdrijf!
Really appreciate it!  :)

It really pays off that I visit the Stunts Forum every now and then!  ;D
Thank you all and a Happy New Year 2019!

Thanks, you too.



I will put the 1.1 together in the coming week. I haven't encountered any new bugs, nor have I had any change of heart regarding the performance, so there will be minor visual and text fixes only.
Title: Re: Stunts goes Dtm
Post by: Overdrijf on January 08, 2019, 03:00:20 PM
This doesn't actually seem to completely fix the "wheels running off" bug (less dramatic than it sounds), but it might reduce it, and the name is fixed. Assuming that I put this together correctly. (If the BMW is still called M30 somewhere, call me (an idiot).)

This new version 1.1 package contains the complete cars, you can paste it over the old ones if you have them or just use this package if you don't. The car behavior is the same as in the 1.0 version.

(I also started on a graphics fix for the superkart since I was going back into Stressed anyway. But that one is a bit more messy...)

(Edit: Just noticed the front wheelhouses of the Audi don't look as intended in the selection view. I suppose that's a detail that'll have to stay as it is. I didn't even catch it myself, so it's not a very big thing, and there's even something to be said for this look. The driving model does look as intended.)