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.

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

Keiran

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

(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.)

I gotta send some of these: 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.. !!

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.

Quote from 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.

You're correct (suddenly flying is the fault of the collision system applying a force which overwhelms the effects of "gravity").

(

Quote :

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.

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.

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.

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.

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.

Quote from 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.

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

Quote from 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.

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

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

Quote from Paranoid Android :

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?

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

Quote from Ball Bearing Turbo :

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

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

Quote from Vendetta :

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

I was thinking the same many times already.

That would be great fun

Quote from AndroidXP :

...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.

Quote from SamH :

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!

Quote from Jakg :

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!

Quote from AndroidXP :

(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.

Quote from Vendetta :

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

Or at the end of the long bridge in South City

Quote from SamH :

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.

Quote from SamH :

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

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...