Gravity in LFS

[joeynuggetz]

Just saw a post over on RSC where someone mentioned that gravity in rFactor seemed really weird. I guess there's a new dune buggy mod out. Anyway, I tried it today and noticed the same thing. Dune buggy mod was pretty kool. There's this one part of the stunt track that comes with the mod wher you approach a tall summit on the track and when you get to the top, you go flying if you go fast enough. Since you couldn't really get airborne with any of the current cars, I never noticed until today. It's almost as if your floating on the moon.

Is this the same in LFS and does it mean that without a proper gravity model, the car physics may as well be made up? I think I've used the editor to make some ramps in lfs and it didnt appear as if I floated off of it. Seemed fine. Maybe someone can comment.

[keiran]

LFS is fine, just try autocross or rally cross. I reckon this is more proof really that the LFS physics engine is by far more detailed than that other game :p

Keiran

[AndroidXP]

The gravity is 100% spot on. I mean, how hard is it to simulate something accellerating at 9.81m/s²? Gravity is probably the first basic thing you program into a racing sim, yet rFactor fails at it.

The collision detection bugs have nothing to do with gravity, they just generate insane forces and catapult you in the air, but gravity gets you back down to earth everytime, that's guaranteed :tilt:

(Besides that, did you notice that LFS even simulates the rotation forces generated by the engine? When you rev up, you see the car nudge to the side a little bit. Also on some track areas outside of the normal drivable track, when you start falling through the ground, just rev up and notice how the car slowly starts rotating.)

[Boris Lozac]

I gotta send some of these: :thumb: :thumb: :thumb: :thumb: :thumb: :thumb: for the team!!. I never tried those ramps stuff in LFS so i didn't know how the gravity is done! But now that i know.. :thumb: !!

[deggis]

Rapid flights towards moon after crashes doesn't have anything to do with gravity. Or am I wrong? The collision detection which doesn't work currently is a different thing. :)

[the_angry_angel]

Rapid flights towards moon after crashes doesn't have anything to do with gravity. Or am I wrong? The collision detection which doesn't work currently is a different thing. :)
You're correct (suddenly flying is the fault of the collision system applying a force which overwhelms the effects of "gravity").

[Ball Bearing Turbo]

(Besides that, did you notice that LFS even simulates the rotation forces generated by the engine? When you rev up, you see the car nudge to the side a little bit. Also on some track areas outside of the normal drivable track, when you start falling through the ground, just rev up and notice how the car slowly starts rotating.)

Indeed I did notice, and if you run with an open diff on a reardrive car, it affects which wheel breaks loose. Notice the front drive cars also have a mild hop since the engine is transverse mounted. Very cool indeed. There are SO many subleties about LFS that make it what it is.

[Gimpster]

The more I drive the different cars in LFS and explore the handeling envelopes, the greater my understanding of vehicle dynamics and vehicle setup becomes. There are so many different ways to get a car to do the same thing, each with different side affects.

I recently think I hit on a new issue. Sudden snap oversteer under cornering may be a combination of suspension bottoming out and if soft tires are used, the tire rolling over to the sidewall.

[joeynuggetz]

Thank you guys. I hope my original post didn't sound like I was doubting LFS. I 've jumped a ramp or two in LFS and it's nothing like it is in rF. I just think that gravity is the fundamental force acting upon moving objects in the sim and if you blow that, what does that say about your physics model? Since I tried to duplicate this in rFactor, I'm starting to think we've all been swindled into believing that rF has great physics. I mean, driving LFS and rfactor is like night and day. Steering feels so natural. The wheel returns to center when you expect it to in LFS, in rFactor it does not. Oversteer in rFactor, too bad - you're gonna wipe. Do that in LFS, apply some opposite lock which feels so natural and damn near kicks in by iteslf, more like a real car would.

[jtw62074]

I'd be very surprised if any sim gets gravity wrong. All you do is add a vertical force to the car once each step equal to, get this, the weight of the car. Bingo. Perfect gravity model. :smileypul

[NetDemon01]

A tad off topic, but where do you get these ramps at in LFS? I can't find them in the objects list in user view or anything, just hay bales, posts, chalk, ect.

[B2B@300]

I'd be very surprised if any sim gets gravity wrong. All you do is add a vertical force to the car once each step equal to, get this, the weight of the car. Bingo. Perfect gravity model. :smileypul

But wouldn't you have to apply the force towards the center of the vitual world? Not just straight down relative to car. So still requires vectoring, so some potential to get it wrong :D

[Paranoid Android]

A tad off topic, but where do you get these ramps at in LFS? I can't find them in the objects list in user view or anything, just hay bales, posts, chalk, ect.

They are only available for Blackwood, that means you can use them for the blackwood tracks and the car park...

[NetDemon01]

Oh ok thank you very much. I was looking through the objects at the autocross park I believe.

[Ball Bearing Turbo]

They are only available for Blackwood, that means you can use them for the blackwood tracks and the car park...

That really bugs me, why must they only be available for BL? :shrug: :(

I never think of that while I am on here so seems like as good a time as any to whine

[Vendetta]

That really bugs me, why must they only be available for BL? :shrug: :(

I never think of that while I am on here so seems like as good a time as any to whine

Yeah, i would LOVE to put ramps at the very top of the downhill part of Aston. That would rock :D

[ATHome]

Yeah, i would LOVE to put ramps at the very top of the downhill part of Aston. That would rock :D

I was thinking the same many times already.

That would be great fun

[SamH]

...did you notice that LFS even simulates the rotation forces generated by the engine? When you rev up, you see the car nudge to the side a little bit.

YES!!

I'd been playing the demo for about a month or so, and sat down to my friend's fully licenced PC. I spun on a corner in a FOX, I think it was, and I was sitting on the curb with 2 wheels off the ground. I revved the engine, and... bugger me!! the thing rocked from side to side!!

This was the moment I got my credit card out for my S2 licence! I haven't looked back since. I knew, there and then, that if THIS aspect of the car's dynamics were written in already, at S2 Alpha, then EVERY attention to detail would be paid to the physics development of LFS. Nothing that I've seen since has dissuaded me from this belief.

[Jakg]

YES!!

I'd been playing the demo for about a month or so, and sat down to my friend's fully licenced PC. I spun on a corner in a FOX, I think it was, and I was sitting on the curb with 2 wheels off the ground. I revved the engine, and... bugger me!! the thing rocked from side to side!!

This was the moment I got my credit card out for my S2 licence! I haven't looked back since. I knew, there and then, that if THIS aspect of the car's dynamics were written in already, at S2 Alpha, then EVERY attention to detail would be paid to the physics development of LFS. Nothing that I've seen since has dissuaded me from this belief.yesterday when i lost the internet, i just sat with a custon view in front of the car revving the FZR, god that makes a nice noise!

[SamH]

yesterday when i lost the internet, i just sat with a custon view in front of the car revving the FZR, god that makes a nice noise!

When I lose the Internet, all I can do is pace about the house in a cold sweat. I must try this LFS therapy next time!

[SlamDunk]

(Besides that, did you notice that LFS even simulates the rotation forces generated by the engine? When you rev up, you see the car nudge to the side a little bit...
Yeah, that's one of the many little details that I've always admired greatly.

[Ball Bearing Turbo]

Yeah, i would LOVE to put ramps at the very top of the downhill part of Aston. That would rock :D

Or at the end of the long bridge in South City :D

[joeynuggetz]

YES!!

I'd been playing the demo for about a month or so, and sat down to my friend's fully licenced PC. I spun on a corner in a FOX, I think it was, and I was sitting on the curb with 2 wheels off the ground. I revved the engine, and... bugger me!! the thing rocked from side to side!!

This was the moment I got my credit card out for my S2 licence! I haven't looked back since. I knew, there and then, that if THIS aspect of the car's dynamics were written in already, at S2 Alpha, then EVERY attention to detail would be paid to the physics development of LFS. Nothing that I've seen since has dissuaded me from this belief.


Well said my friend. And the feel at the wheel is so damn real i cant really justify playing other "sims" unless its just for fun.

[Shotglass]

This was the moment I got my credit card out for my S2 licence! I haven't looked back since. I knew, there and then, that if THIS aspect of the car's dynamics were written in already, at S2 Alpha, then EVERY attention to detail would be paid to the physics development of LFS. Nothing that I've seen since has dissuaded me from this belief.

it was already coded into s1
but its still a bit flawed ... for one the flywheel doenst seem to influence weight at all and more improtantly if your car is too light the engine can spin the whole car high into the air in idle

[Hyperactive]

The engine revving and the car nudging-thing was in GPL and has been in many other games as well so that's nothing new ;) If I recall it right...

[Ball Bearing Turbo]

it was already coded into s1
but its still a bit flawed ... for one the flywheel doenst seem to influence weight at all and more improtantly if your car is too light the engine can spin the whole car high into the air in idle

The flywheel doesn't influence weight, it influences rotational inertia :D

And how light of a car are you talking? 5 lbs? It's not relevant how it behaves in impossible conditions. :shrug:

[Shotglass]

And how light of a car are you talking? 5 lbs? It's not relevant how it behaves in impossible conditions. :shrug:

cars in the 100-200 kg range

[Hallen]

Yep. Using the old Tweak program, you could make the engine really powerful, and put in a really heavy flywheel. The car could litterally do barrel rolls from a standing start. :pillepall Just floor it and the car would fly up in the air and roll over to eventually come back down on the wheels. Somebody did a video of it. You might still be able to find it on the LFS video site.

[Hyperactive]

Isn't that how it should happen? I mean, 1000kg flywheel, 50000hp engine, 200kg car... barrel roll...

...If you would build such a car un real life it would probably do the same. It's the absurd specs of the car, nothing more (50khp engine weighing 100 kilograms would be nice to see ;))

[Ball Bearing Turbo]

Indeed I suspect it's the bizarre input that creates the bizarre output.

[Shotglass]

Isn't that how it should happen? I mean, 1000kg flywheel, 50000hp engine, 200kg car... barrel roll...

and how exactly would a 1 ton flywheel in a 200kg car work ?

[Ball Bearing Turbo]

Lol

edit: so it's impossible, but so are the specs of any car that behaves that way in LFS
edit2: what is that foreign substance you're spraying at me?

[Shotglass]

edit: so it's impossible, but so are the specs of any car that behaves that way in LFS

might be ... but with mechanik s2 you cant change the flywheel weight so that the only thing you change is idle torque
but what happens if you start toying around with the cars weight is that there will be a threshhold where the car stands still in the setup screen and if take away only one more kg it suddenly takes off into orbit

edit2: what is that foreign substance you're spraying at me?

you dont want to know

no seriously ... you dont

edit: you dont even have to change the engine at all ... just take the xrt and set its weight to -1,670 it will instantly take off in the setup screen even though it weights a healthy 495 kg ... as soon at you ptu the driver in itll behave normally

[Ball Bearing Turbo]

you dont want to know
no seriously ... you dont



I kinda do, but ok, I'll be searching all over for that bottle to find out on my own. Combing the shelves at every store, I shall be. Then I'll get my OWN spray in MY avatar, MOHOOhahaha

edit: you dont even have to change the engine at all ... just take the xrt and set its weight to -1,670 it will instantly take off in the setup screen even though it weights a healthy 495 kg ... as soon at you ptu the driver in itll behave normally

K, well you're setting the weight factor to a negative number. The problem is that our finite minds cannot grasp what number in Scawen's virtual cosmos of pseudo-physical systems we are altering in order to get our vehicle weight. We're not just entering the weight directly, and therefore you do not know what else you're screwing around with by putting in a negative number. Things are not so straight foward in "Scawenia" (that's the name of his world BTW)

[Bob Smith]

Hehehe - actually I think that problem is to do with the CoG of the car minus driver moving infront of the front wheels, so the car tips over and goes weee... with the engine having positive weight just behind the wheels and the body having a large negative weight from even further behind, it's just goes spinny spinny.

[Shotglass]

hmmm interesting thought bob ... might also explain why you can go lower on a smaller displacement engine even if it has more torque ... so maybe the engines weight has nothing to do with the weight factor and is calculated from the displacement and number of cylinders

[Ball Bearing Turbo]

so maybe the engines weight has nothing to do with the weight factor and is calculated from the displacement and number of cylinders

Indeed, this is definitely true I recall noting that back in S1, where if you modified nothing but the engine specs the car would sit different on it's suspension. :thumbsup:

[Chaos]

Just for the curious, here is the thread (http://forum.racesimcentral.com/showthread.php?t=243378) about rFactor's "gravity" :tilt:

[Frankmd]

I dont think the gravity model of rFactor is wrong. I think the mass, or massdistribution of the rFactor cars is wrong. I recall reading something about massdistribution for the porsche cars in rF. They were not realistic, but did provide a realistic Porsche-handling. The discussion was wether this trick was a bad or a good thing.

But it could also be just a bug when a car is at some special spot. Maybe the gravity is correctly modelled when the car is on track.

[Hyperactive]

I was reading that thread on RSC about gravity in rf and it was so funny and frustrating to read all those troll posts from rf fanboys saying that you need phd in physics to tell if there is something wrong with gravity in rf.

If the car floats it's more than just a bug - it's a feature (called rf physics). Real cars don't float...

At least people here don't blindly believe that LFS is perfect - how could it get any better then... :D

PS: how do the cars float in rf? any video to show, anyone? I don't have rf so I'm littlie limited with comments... Don't want to post in RSC, the behaviour of the mods seem to get worse and worse...

[Funnybear]

maybe this is why Scawen and the team chose not to go with production or known cars(Except the obvious licencing issues). This way they are not contrained to making a Ferrari handle like a Ferrari should or make a porsche handle like the arse slidy slippery engine over the rear axle bitch from hell that it is. By going in without any preconceptions of car handling they can get the physics right and in a way worry about the cars later. That thought struck me from reading the 'alertnative' thread about the ISI engine and Rfactor crazy gravity. Someone mentioned that the Porshe handled in a porshe like manner. That very statement shows what 'rival' sims are trying to do, make a ferrari handle how poeple think a ferrari should handle like, not like how it handles in real life.

I feel that LFS is giving us a 'real' physics engine, where gravity remains constant regardless whether you are on the track or 1/2 mile above it. The cars then behave appropriatly whether people regard them as handling accuratly or not. If the physics is correct then the car handling should theoretically be the most accurate it possible can be.

I'm still with LFS on this, gravity is a constant. IT should be constantly applied everywhere through out the sim. If it's not then it's not simulating anything is it.

[ste_]

My personal opinion is that LFS doesn't do gravity properly. It doesn't seem to use a constant downward acceleration. Take a UF1 on FE-Club and pull a jump on any of the sidehills. Once the car has reached it's max height, it seems to fall to the ground at constant velocity, rather than accelerating. The cars should hit the ground with much more force than they currently do after being airborne. (It's almost like they reach terminal velocity far too quickly, and then after than it's a constant drop to the ground)

[Funnybear]

They are not exaclty falling from a great height though are they, by the time you would have registered that there is no acceleration towards mother earth you would be eating worms. The time is too short to measure any acceleration just by a feeling . . . . Maybe if we strapped some very sensitive scientific instruments to the car and drove it off one the tower blocks in So City, then you might get a reading that corroborates your 'feelings'.

[Hyperactive]

My personal opinion is that LFS doesn't do gravity properly. It doesn't seem to use a constant downward acceleration. Take a UF1 on FE-Club and pull a jump on any of the sidehills. Once the car has reached it's max height, it seems to fall to the ground at constant velocity, rather than accelerating. The cars should hit the ground with much more force than they currently do after being airborne. (It's almost like they reach terminal velocity far too quickly, and then after than it's a constant drop to the ground)

Is there any way to use some replay analyser to check it? Hmm, me puts white coat on and starts LFS...

[Funnybear]

You get the car, I'll get the feather. Meet you at the top . . . .

[tristancliffe]

Gravity isn't a constant at all. It just so happens that the average value at sea level over the earth is 9.80665 m/s/s. A higher altitudes (out the range of a racing sim) it decreases.

Not that it matters, but I wonder if LFS's gravity is constant or if Scawen programmed it to take into acount altitide variations :scratchch:

[Funnybear]

Seeing how LFS has a graphical celing (the sky box) then I would have thought not, just superfluious code that would never be needed.

[Hyperactive]

I think you lose very little realism if you use constant g of 9.81 m/s2.

I can't seem to find any way to check the gravity in LFS, but for me it looks ok... did some test runs at blackwood with XRT, I had put some ramps on the main straight but there is no vertical acceleration/velocity number available...? Maybe put the ramps on the pit straight to get more air to the jumps---but that's a bit too much :) (or just try to get some strange collision happen where the car "jumps" very high and...)

But I'll think I do some online racing and go sleeping... :)

[Ball Bearing Turbo]

... Just downloaded your videos, I have just one comment:

What the hell kind of a "sim" is that? People compare that to LFS? I never tried rF, and after watching that it's not a likely occurance, I can tell you that... LOL

edit: and the download speed was great for me, 400kb/sec took no time :)

[detail]

Gravity isn't a constant at all. It just so happens that the average value at sea level over the earth is 9.80665 m/s/s. A higher altitudes (out the range of a racing sim) it decreases.

Not that it matters, but I wonder if LFS's gravity is constant or if Scawen programmed it to take into acount altitide variations :scratchch:
Yes, at the top of mt. Everest the gravity is 99,7% of that at the sea level. At the height of Alpha orbital station the gravity is 85-90% of normal.

It was funny to modify the constant to make gravity at the level of Mars... Everything is so slow and the jumps are can be high. :)

[GP4Flo]

It's really frightening, that there are so many people in the RSC forum talking about things they don't seem to understand. If you don't know what you are talking about, let it be or take a look at a physics book first. Gravity on earth is just g = 9,81 m/s². To calculate the gravity for a car you take it's mass and multiply it with g to get the downwards force. Nothing complicated, just simple math: F = m * g.

I can't really understand how you can program gravity wrong. :shrug:


Edit: Thanks for the correction Frank.

[GP4Flo]

I just did a test and the values LFS shows in the g-meter and in the raf file are a bit strange: When rolling the car to it's side, you would expect the lateral acceleration to show exactly 1 g. But it doesn't, it just shows 0 g. Did you make similar experiences? :scratchch

My guess is, that LFS removes the gravity acceleration from the g-meter and raf outputs. Maybe Scawen can confirm this?

[detail]

GPFlo,
1) gravity force can be calculated from absolute acceleration (a = F/m). We can obtain the acceleration quite enough precisely as the 2nd derivative of position. From the difference of positions of a car in 2 moments we get it's speed, from the differences of speeds - the acceleration. No need for extra data bytes.

You just need to jump from a ramp and get the vertical acceleration.

2) Gravity constant is there in the memory, search for "-9.81". :)

[Funnybear]

See. Look at that. Somebody who is clever. I like clever people. More cleverness please. Bring on the Cleverness. More people who know about physics and science and stuff please. I like reading about clever stuff like that. Because I havn't a hope in hell of understanding any of it but it makes me feel cleverer just reading it . . . .

Big cheer for the clever people.

[GP4Flo]

1) gravity force can be calculated from absolute acceleration (a = F*m). I think you mean a = F/m. I've just tested it. The tyre load on all 4 tyres is 6,3 kN according to F1PerfView. With a mass of m = 678 kg I get g = 9,3. Something's wrong there :scratchch


2) Gravity constant is there in the memory, search for "-9.81". :) That answers Tristan's question :)

See. Look at that. Somebody who is clever. I like clever people. More cleverness please. Bring on the Cleverness. More people who know about physics and science and stuff please. I like reading about clever stuff like that. Because I havn't a hope in hell of understanding any of it but it makes me feel cleverer just reading it . . . .

Big cheer for the clever people.If there is something you don't understand, feel free to ask. But please don't post comments like this. It's not our fault when you missed the physics class at school ;)

[Funnybear]

Mate, that was slightly unfair. I love reading shit like this. I love finding our about the science behind everything. I'm not dissing you and wasn't even trying to derogate any of you discussing this aspect of LFS. I am actually following it in a fairly well eduacated manner, I may not have a PHD paper on advancing the weak force in String theory but for a layman I try very hard. I will tone down my humour, obviously some of it is escaping your monumentous intellect.

Please carry on with the science. I shall just watch and learn. Last thing I want is to hijack an interesting thread and turn it into a petty arguement about . . . . . random stuff.

[GP4Flo]

Mate, that was slightly unfair. I love reading shit like this. I love finding our about the science behind everything. I'm not dissing you and wasn't even trying to derogate any of you discussing this aspect of LFS. I am actually following it in a fairly well eduacated manner, I may not have a PHD paper on advancing the weak force in String theory but for a layman I try very hard. I will tone down my humour, obviously some of it is escaping your monumentous intellect.

Please carry on with the science. I shall just watch and learn. Last thing I want is to hijack an interesting thread and turn it into a petty arguement about . . . . . random stuff. Ok, sorry for the harsh words. I was just a bit dissed, because there are so many people around who talk about things they don't understand (just read the comments over at RSC à la "you would have to program gravity for each situation" or "gravity isn't important for a racing game". Then when there is someone like detail who knows what he is talking about and actually does some research about the subject, a comment like yours follows.

I mean this is just plain simple physics. Nothing complicated like "string theory", not even Einstein's theory of relativity is important here. We are talking about things Galileo Galilei has found about 400 years ago.

[deggis]

... Just downloaded your videos, I have just one comment:

What the hell kind of a "sim" is that? People compare that to LFS? I never tried rF, and after watching that it's not a likely occurance, I can tell you that... LOL

edit: and the download speed was great for me, 400kb/sec took no time :)
That was just a some weird dune buggy mod with a stunt track. :D And that Porsche was taken from another mod... just to clarify this to you. :D

[Frankmd]

It's really frightening, that there are so many people in the RSC forum talking about things they don't seem to understand. If you don't know what you are talking about, let it be or take a look at a physics book first. Gravity on earth is just g = 9,81 m/s². To calculate the gravity for a car you take it's weight and multiply it with g to get the downwards force. Nothing complicated, just simple math: F = m * g.

I can't really understand how you can program gravity wrong. :shrug:

Weight = downward force
You take the mass and multiply it with g to get the downward force.

[Hyperactive]

If the car is floating (downloading the video) the problem is not about gravity when the car is on the track, it's a problem with the gravity when the car doesn't touch the ground. There was also one post at RSC which made me really think wtf.: check it (http://forum.racesimcentral.com/showpost.php?p=2891163&postcount=5). Is it a value defined in the mod or is he actually suggesting what I fear he is...?

Before you can actually show any scientific stuff about accelerations and velocities in any sim you need to know how and what values are being calculated and combined in that value you are looking at. Example: the acceleration value. Does it only include the x and y components or is the z component also in it? What about accelerations caused by car/wheel rotation?

So instead of simple
a = sqr((ax)2 + (ay)2)

it can be:
a = sqr((ax)2 + (ay)2 + (az)2) + (v2 / r)

Where:
sqr = square root (hope I'm using the right terms...)
(ax)2 = acceleration to x(/y/z)-direction without the acceleration caused by rotation
v = 2 * PI * n * r = velocity of the point which is rotating around a center point, at the distance of an r.
n = rotations per second (the car...) You can also have the three (x,y,z) vectors here, but it just makes it more complicated without showing anything new or interesting. (the car rotates around the axles, around x-axle, around y... and these would be summed in similar way as the accelerations above.
v2 = v * v = velocity * velocity

(all vectors)

I need to look at the F1perf's values...

EDIT: after looking at those videos it just seems that the aero model does only care about the forces that point directly against the car's nose (drag). And the gravity doesn't accelerate the car when it's dropping down, the velocity seems to be constant. Which it isn't. I expected much worse, like the cars sliding in the air or something (phew). :)

[Scawen]

I think you mean a = F/m. I've just tested it. The tyre load on all 4 tyres is 6,3 kN according to F1PerfView. With a mass of m = 678 kg I get g = 9,3. Something's wrong there :scratchchThat force you see in F1PerfView (from the RAF file) is the force supporting the car body. It excludes the unsprung mass (wheels etc). So that should explain the error you see.

[Fonnybone]

I just did a test and the values LFS shows in the g-meter and in the raf file are a bit strange: When rolling the car to it's side, you would expect the lateral acceleration to show exactly 1 g. But it doesn't, it just shows 0 g. Did you make similar experiences? :scratchch

My guess is, that LFS removes the gravity acceleration from the g-meter and raf outputs. Maybe Scawen can confirm this?

Well, MY guess is that the LFS g-meter shows acceleration forces,
not the force exerted by gravity. Once the car is on it's side and not
moving (lying on the ground), it's not accelerating. An immobile object
isn't accelerating. However, if you were to drop the car from the air while
it's on it's side, it should (and im sure it would) reach 9.8m/s² of acceleration.

Oh, and i'm pretty positive LFS uses a fixed constant around 9.81 to
simulate gravity. Also, since the 'worlds' are relatively small, the gravity
is applied linearly, downwards, not towards a virtual center.

[Ball Bearing Turbo]

Ok, sorry for the harsh words. I was just a bit dissed, because they are so many people around who talk about things they don't understand (just read the comments over at RSC à la "you would have to program gravity for each situation" or "gravity isn't important for a racing game".

Indeed, I browsed that link CP had to the RSC rF "discussion", and I was a bit shocked at the attitude there TBH (call me naive or what!) I think at least we are lucky to have some very learned individuals (and the odd BRAINlien (brain alien)) who can enlighten us laymen to some great thoughts. I actually laughed out loud for real in that forum, and they call US "fanboys" over here, LOL. :pillepall

[AndroidXP]

Ha! Now we have someone to blame for being hated by the rFactor community :razz:


I have to agree though - as I read those posts on RSC I was literally like ":pillepall" and ":doh:"

[J.B.]

I have to agree though - as I read those posts on RSC I was literally like ":pillepall" and ":doh:"

Indeed. Made me realize that the LFS community is actually quite a nice place. Nobody goes mental here when someone makes a valid critisism of physics.

[Bob Smith]

Nobody goes mental here when someone makes a valid critisism of physics.
That's because we've got some in the first place to criticise. ;)


/runs

[Ball Bearing Turbo]

Good one bob :D

[AndroidXP]

:iagree:

[TechAde]

Besides that, did you notice that LFS even simulates the rotation forces generated by the engine? When you rev up, you see the car nudge to the side a little bit. So does rFactor, RevItUp.wmv (http://www.amja.co.uk/rF_Images/RevItUp.wmv).

Don't shoot me, I think both LFS and rFactor are superb, however I'm enjoying rFactor more at the moment. When S2 comes out of alpha I'm sure LFS will get plenty more of my time.

I've spent a lot of time tweaking my forcefeedback and controller settings in rFactor and I can assure you that when configured the way I've got mine the "automatic" countersteering effect is very much in effect (I run a DFP @ 900 degrees of rotation), and in no way is it a case of "oversteer = oh dear".

[AndroidXP]

Yes, but in LFS this effect is archieved by putting a force on the car body, which in return compresses the suspension, so the whole thing does also work while airborne.

In rF I guess* it's just one of the other numerous canned effects, that either just moves the view or artifically compresses the suspension, so I'm not quite sure if it even has an influence on the physics calculations respectively if it would change the roll of the car whilst revving up midair (which I don't really think looking at the obviously flawed gravity).

But whatever, no reason to have an argument over it. For me, rFactor or any other current sim will never come close to LFS and for some people it might be the exact opposite. No amount of arguing is going to change that. :)

* I'd actually research it if the rFactor guys bothered to put out a demo

[Frankmd]

I guess it would be easier to just simulate a force, rather then creating some code that allowes you to artificially move the cockpit, while it actually isnt moving etc.. If you are able to simulate 4 tyres and downforce, it shouldnt be too hard to apply a moment somewhere on the car that is proportional to the rotational speed of the engine.

[TechAde]

Yes, but in LFS this effect is archieved by putting a force on the car body, which in return compresses the suspension, so the whole thing does also work while airborne.

In rF I guess* it's just one of the other numerous canned effects, that either just moves the view or artifically compresses the suspension, so I'm not quite sure if it even has an influence on the physics calculations respectively if it would change the roll of the car whilst revving up midair (which I don't really think looking at the obviously flawed gravity). My guess would be that it's not a canned effect, but I don't have any evidence either way, all I'm going on is how it feels to me, and it sure doesn't feel like a canned effect. I'm not quite sure what this has to do with whether or not rF gravity is borked, or if you've been following the gravity thread over at RSC, but it seems to have been proved that the gravity is not flawed. ["Seems" - once again I've done no research of my own, so I'm not really in a position to comment]

But whatever, no reason to have an argument over it. Totally agree, however nowt wrong with a reasoned discussion :thumb:

For me, rFactor or any other current sim will never come close to LFS and for some people it might be the exact opposite. No amount of arguing is going to change that. :) Fair enough, but I reckon you'd be pleasantly surprised if you came and had a few laps on my rFactor setup.

* I'd actually research it if the rFactor guys bothered to put out a demo Yup, there really should be one I agree, although at the rate they're adding new features to the core I guess a demo isn't top of the priority list.

Sorry if I'm coming over as argumentative, I'm not meaning to be. I dream of the day when rF'ers and LFS'ers can co-exist in perfect harmony, just like they co-exist on my hard drive :D

[jtw62074]

Engine torque reaction on the chassis is about as hard to do as gravity ;) I doubt it's canned anywhere nowadays. It's much easier just to do it properly instead.

[Hyperactive]

I guess it would be easier to just simulate a force, rather then creating some code that allowes you to artificially move the cockpit, while it actually isnt moving etc..
...

If you have the forces to simulate ;)

I think it is possible to create a fairly good simulation using only canned effects but in the end you can't write every aspect of racing in this "if -> do" way. If you create realistic physics that do the right calculations even if the car is upside down you don't need to code the "car upside down" part anymore. Using canned effects is by far easier because you don't need to understand what is really goin on. Just set the variables so that the car acts like you feel it should. While it does so in some predefined cases in some cases it may acts totally unrealiscally, like car upside down could be "falling towards the sky" because the gravity is very simple made :)

So when using canned effects you can never be sure that the outcome is realistic if one of the variables change unexpectedly, like the car lifts one of its rear wheels in turning or the car hits a bump when the car is sliding upside down after an accident.