Friction

[Ree]

I need a bit more information regarding grip in C2. Both friction angle factor and traction fractional multiplier seem to increase grip. What's the difference between them?

[Small Block]

The friction angles represent the angle from the car's (center of mass) Z-axis until which wheels have grip. The first # being movement towards the outside of the wheel, the 2nd towards the inside.

The traction fractional multiplier is the amount of traction the wheel has when it's not slipping(outside the friction angles).

[Ree]

The first part is kinda tricky... an example or a more detailed explanation would help.

Regarding the traction multiplier, according to your explanation it does not directly affect tire grip, it seems to affect performance of the vehicle while 'climbing' steep grades or pulling cars/obstacles when wheels are not slipping. Correct?

[Small Block]

Try to visualize it as a deviation from the wheel's z-axis: you've got your z, which is the line the wheel rolls on, and on each side of it, an angle inside which friction is still possible. When you turn, the center of mass exerts lateral effort on the wheels. Depending on the steering angle, car speed and COM coordinates, this will or will not make the wheel contact the road beyond the friction angles and slip.

You have one angle for slipping outwards, another for slipping inwards. This is to simulate the camber curve, I think. Obviously, putting a value of 90 degrees there means that the wheel cannot lose traction in the direction of that value.You can simulate a live axle/beam suspension by having little to no spread b/w the 2 angles(solid axles obviously have no camber variations and C2 can't simulate what specific physical reactions they actually have). This will make the "wheels" totally parallel, and as such, actually force you to countersteer to avoid spinning out.

The traction multiplier does actually work all the time, I think C2 manages the 2 factors jointly, IE a high-traction wheel will keep more grip while spinning than a low-traction one. That's probably whgy it's called "fractional multiplier" and not "grip value".

[Ree]

Now tell me if I understand the thing correctly. When you steer a car (let's say suddenly at high speed) it's obvious the car 'would still like' to go the direction it was going before because of inertia. Steering 'tries' to make the car go either left or right so I could say it 'tries' to rotate the whole car either left or right. Now let's say Z' is Z axis of the car before the turn and Z'' is Z axis of the car after the 'would be' rotation. So if the angle between Z' and Z'' becomes wider than the friction angle of a wheel which is on the opposite side of the car compared to direction of the turn, that wheel would lose grip. If it's not the way I think please tell me it's not.

[Small Block]

That's essentially it. To maintain grip, the COM must be moving on a vector that's inside the friction angles. The keeping of grip is thus dependent upon how the COM's vector combines w/ the wheels' positions.

[Ree]

Should I make both friction angles have same values? And how do I know a good friction angle setting (and traction fractional multiplier as well) for a particular car? What should I base my decision on?

[Small Block]

You essentially have to try different values. Keep in mind that most cars are designed to be relatively coherent and safe to drive, so extreme variations typically don't yield good results. If a car is scaled right and the rest of the parameters are more or less correct, you'll probably find that there's a very small range of values that yield an acceptable handling.

Typically, whithin that range, the car feels o.k. Smaller angles and it's like driving on ice, wider ones and it starts having supernatural grip/lose it brutally and w/o warning.

[Ree]

But should I have both friction angles set to the same values?

[Small Block]

Only if you want to simulate a solid axle. Independent wheels should have some spread b/w the angles. Typically, the 2nd # is higher than the first. Just try different combinations/values, it's not too hard to pick up the difference.

[Ree]

All right, thanks for the info.

[C2 Scientist]

You got my attention with these friction angles... what do you use yourself nowadays? And are they realistic enough in your opinion?

I myself have used 83,83 for front wheels, and 79,83 for rear wheels... it buggers me a bit that the steering is quite slow with keyboard... but somehow I don't think it could get much better with keyboard anyway...?

GTA III-styled steering would be nice... it's quite fast though, so maybe it would go better with the fun-versions...

[Ree]

I have always been using 79/81 on all typical muscularities I've got in my game. That works pretty well, might be slippery a bit for some. I don't know a really good value, it's personal choice what makes you like it one way or another. I just wanted to find out how it works and which could be good values and I'll guess I'll stick to my current friction angle values and some modified traction fractional multipliers.

Btw, C2 is for crashing fun, so that's not that important if it's more/less 'grippy', I guess. I choose NFS5 for serious driving fun (since the file format is already cracked).

[TTR]

"Already" he says...

[Small Block]

Depends on the car, actually. I find most 60s thru 80s RWD cars feel fine w/ values like 81.7/82.5 front and 81.7/81.7 rear. Of course, I'm talking standard RWD cars w/ live axle here, not sportscars or euro-sport thingies. The actual angles will vary w/ gravity(higher gravity needs smaller values...I use 2.6 myself, w/ 12000 as a downforce-to-weight value) and scale(a car that's scaled larger than necessary will automatically handle better, as its wheels perimeter will be larger and thus can tolerate smaller friction angles). Some muscle cars have values that are slightly above those, but not by much. Even a 0.1 degree difference can make a car handle too well or too poorly. Again, it'll be more obvious w/ very detailed bboxes(if you use only 8 points, the car WILL handles like a concrete slab no matter what!).

As to the steering, higher values tend to make it a bit slower. The only way to get realistic steering in C2 is to use an analog wheel anyway.

[Ree]

"Already" he says...

Yes, already. That's how it's written.

[TTR]

LOL maybe you ment...FINALLY

[Ree]

Call it what you want. It's still the same.

[TTR]

"God, after 4 years they finally broke it..."

"God, after 1 month they already broke the code!"

Thats NOT the same...

[Ree]

Man, you're funny. The result/fact is the same - cracked. There's no need to pick out my words - the fact that I used 'already' instead of your suggested 'finally' does not change/mean a damn thing. Hey, let's not drag thi out. It's pretty pointless.

[TTR]

You were the one that replied one me, so i just went and tell you what i ment, then you tell me its the same (not telling its about the code ).

But it was about time the finally cracked it

[Ree]

Actually, there's still much to do.

[TTR]

I see, well if they still gonna release NFS's with rice and compitable with PS2's on the net then they got all the time

[Ree]

Do I sense a rice hater? There are so few of them these days...

[TTR]

To tell the truth, i like the stock car ones, like the nissan skyline series, or the toyota supra etc, and some riced ones...but few, you know, like the real race ones that are out there

Like:



Last year i still liked it, but it grew so big and so pointless...wing here wing there...power? LOL forget that..

And since im here i got my love to weird/strange or apoc cars, or muscle cars and even the so called "crud" cars

[Ree]

Race prepared Japanese cars, hey, that's no rice as much as it's not having a baddass exhaust pipe if the car really makes use of it. Both Skyline and Supra are great vehicles Skyline being one of my favorite cars.

[TTR]

Oh ok, then i aint a rice fan either

[Ree]

[C2 Scientist]

Member TTR, step out! The elders have decided you are way too cheery for this board! You crime has been using 's , 's and 's too often, and for this dire mistake you should be punished... badly! But, since you have an avatar picture that fits this board well (which seems cheery too, though), and because you are talented in creating content for the game, we will only beat you up halfway to death, and command you to use 's , 's and 's from now on.

Also, to avoid withdrawal symptoms, the elders have decided it would be best to give you a monthly dose of cheery smileys, so here's the first dose:













Just horrible! Anyway, the elders have spoken, message delivered by me. (ahem)

.

.

.

And don't you dare to reply to this with a '', or we'll let Raven-X teach you some manners!

(<- exception)

[TTR]

you funny..

Oops