Heat Physics Clarification

[Punko]

Hi guys,

I haven't posted anything here in a while, but I stop by frequently to keep up on the F2000 news.

I read all the posts including the long winded and often amusing posts by some of the more colorful members.

I have to make a couple of corrections that I have read about Nascar Heat physics that may be misleading to some of you.
(I will paraphrase this rather than dig the quotes up)

1. The F2000 has Nascar car shell that you can not get rid of.

Not true. We can specify the length width and height of the body.
the physics file reads:

mx 35749
my 46446
mz 7849

These are the mass values of the car itself. This uses a complex formula to calculate the final numbers you see here.

width 70.0
height 37.0
These figures tell the Game engine how big the body is.

ftrack 65
rtrack 59
wheelbase 102

These figures tell the game engine where the tires are. (track is from the inside of the wheels).

You can prove that you are not driving a "Nascar shell" by going out and locking wheels with another car and see what happens.


2. You do not have a front wing. it is grill tape and that can not act as a front wing.


Completely false.

the physics file reads:
fspoiler_lift -.0, -.59
fspoiler_drag .016, 0.16
rspoiler_lift -0, -.80
rspoiler_drag .0201, .201

We can control all aspects of the front wing to make it is large or as small as we wish, as well as add the required amount of drag for each wing.


You say that the car overheats when you put the wing at the higher settings and that is why it is "grill tape". the reason is because Heat ties in engine friction to the amount of front wing. I may have not reduced the friction enough to negate that.

3 Nascar has a canned slide when you put the car sideways.

Not true.

I don't know any other way to explain this as it is a function of weight, tire grip. and roll centers of the physics.

to test this, go download our Lotus F3 and slide it around. Then download our Ferrari Challenge and slide that around.
The cars are very different. True you can slide any car to the point of no grip and you will loose it, but how many times have you saved the car even after you have done a 360?


I wanted to clarify a few things about Nascar Heat that my have made some people think that this was still a 3000 pound hunk of heavy metal with an F2000 body.

[Gary Hoorn]

Bob,
Thank you for the clarification of facts which Bobo88 and I were aware of due to our long association with Heat. We have locked wheels and know full well what you say is true. Since we have all of the Mods mentioned we have also noted the significant differences in each of them. Great work by You and the Team...
Gary

[cbonsall]

i didnt know that track measurement was for the inside to inside measurement. then all th convertions i`ve done are wrong.

[Punko]

I should make a clarification on that track measurement, It is from the inside to inside of the hubs. so it really is a little shy of the center of the tires. Since Heat doesn't have any representation of the hubs it is a close guess.

Charlie,
As long as your cars are using real world figures for the track you should be fine. It is more the diference between the front and rear that give the car the feel (within reason of course). The first F2000 was made using the track as the outside of the tires. If you notice if you use real world measurements on your cars you had to move the tires in a little to make them fit inside the wheelwells. (that always puzzled me until I found out why)

[Punko]

Well Peter,

I Guess you really DO know everything!

I must be wrong then,,,

I guess Dave Broske from MGI (the creator of Heat)must be wrong too,,,

They just called it Fspoiler and Fspoiler_drag to fool everyone...

Your right then Peter it probably IS grill tape!

[PeterV]

It doesn't actually matter WHO is wrong, you or Dave. The bottom line is the game has some notable flaws in its reality simulation. Like almost all sims do anyway.
Front wings on open wheelers have very little impact on drag. I don't know what the numbers you listed mean, so this sentence could be off target, but it appears the ratio of front to rear wing drag is far too close.
Heat might only allow percentage steps of front tape adjustment, which in F2000 then links to wing angle approximations of some manner. So I don't know what the real steps of angle adjustment are, which then makes it hard to relate an accurate measurement of angle VS drag. But after a LOT of racing and car setups I can feel it is too much with ratio to what the "wing" angle change benefit has given. And the rear is reverse.....too little drag for benefits gained.

I have driven 4 heat mods and ALL have unrealistic rear end sliding. I am not sure about how unrealistic the others were, I only played them a bit. But I remember it was a commom theme across all the mods. Ask Dave what he did, and I BET he has 'canned' slide in there to some degree. Well, either that or some theories/routines that stray off track once certain limits are passed.
In real life I can save a car from reasonable extremes, or power slide away to my hearts content. Do a 360 and drive away from it with near perfect exit as desired. There is NO limit to how far 'around' you can push a real car, whilst under control still. ie Zanardi donuts and drive-aways (of the past )
But in F2000 Heat it is the opposite! The slightest sneeze causes a near unsaveable rear end slide.Which just KEEPS going, defying real world physics. Which you don't even need to drive a real F2000 ever to know would have to be total crap. And that occurs even in perfectly balanced F2000 Heat setups, which should 'drift' controllably if pushed too hard.
I have actually perfected how to let it keep going right around so I can drive away at the end of that 360!! To do so is quicker than ever possible when trying to save it on the sub-180 side of spin!!
All sim writers use 'cheats' to get around difficult physics scenarios. I bet his tire modelling is far short of realistic too. Though for all I know it could be a great and innovative system he used or came up with.....except it fell short of true to life.
I am also sure he (they) put a LOT of thought and effort into taking the best paths suitable and appropriate. They would have had notable programming and computing power restrictions back then, plus less sim knowledge too.
For its time it is quite a good game/engine, but it has those notable flaws.

I probably know as much or more of the heat engine and its nuances than you. Though all mine is by reverse engineering, testing in game and recording results of actions/reactions, and almost all in the F2000 mod. That combined with reasonable knowledge on programming and car sim physics principles/aims/tricks. Shortcuts used by programmers to "simulate' what they can't do properly. Which is partly why I have an edge on all the secrets for setup ideas that others don't. And why I know how to drive the car in ways that others can't.
And if you think even the most well thought out programming ideas and formulas get a sim to make a car act even 90% as per real, then you are dreaming. They don't have the computing power or the total required knowledge to achieve that on a PC....yet.

If I had a real F2000 I would go out and drive it, then have 100% detail on what is what, and what is not. And could report on it more thoroughly. But I don't.....
But I do a have a very large database of racing experience, and sim experience, to rely on for comparison information anyway. More than enough to know what should be what, and what facts matter or not.

Note that ages back I was the one to point out to others here that the F2000 mod car size was "most likely" set by the collision map of your F2000 car design. NOT the size of a Nascar. Though couldn't be known for sure what level of 'detail' that had. ie rectangular, or more accurate car shaped. And which I 'asked' indirectly for the need of your explanation (if you were to have passed by and read it).
Also pointing out that the 'front engine weight' theory (stuffing up settings and handling) was very likely to be wrong, again due to the game engines car file programming scope.


It is good to have clarifications of factors in the game, which you would have the internal information to impart. So that is always welcomed with thanks.
But it doesn't mean you know EVERYTHING about the game deeper than the mod. Though I am sure you know a LOT!!
And probably a lot more about other engines (like Racer maybe) which have easier access to the design, theories and coding of.

I have nothing but a fleeting interest in DESIGN of sims. Only in their END RESULT. Though I have a friend who is well into his own sim (he monitors Racer and others and explains to me shortfalls in theories and systems they use - or good points). So we have idea 'tossing' now and then (or rather he does), which my useful knowledge can help him see the light better at times. Though 99% of all idea directions come from him. I only get to point out what shortfalls they might have etc.
And that is where a fair amount of my sim 'internals' knowledge comes from too.


PS: FSpoiler/FSpoiler Drag...means nothing.
Sedans have front spoilers....and they tape them up. Which causes more drag too. So what has that terminology cleared up???
Best you actually ASK him what the coding around it all is. THEN get back to me...IF it offers your view any support.
In the meantime RESULTS of testing show what is Most Likely being done.


PSS: Mind you, NONE of all this is any reflection on YOUR F2000 mod!!! As far as I can see it is an EXCELLENT mod. Ranking right up the top end of my big list of a dozen different car sims and all their mods.

[size="1"][ May 28, 2003, 06:21 AM: Message edited by: PeterV ][/size]

[PeterV]

Well the front wing doesn't seem to work 'correctly' to me. Part due to that heat problem, but also a bit from too much drag per change.
Rear wing should give BIG drag gains per angles, fronts should do quite little drag changes for angle changes.
All in all it feels like TAPE to me!! Or some cross between tape and wing.