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#ActualK_J_M

Posted 13 September 2012 - 04:32 PM

Hi.

For my Autocross Racing game i used lateral Pacejka coeficients similar to this curve.

Posted Image


This gives a very forgiving tire with a lot of grip at all slip angles.

I noticed in your second video that your car reaches a maximum slip angle before it loses grip and spins around.
This is classic of a Pacejka curve that peaks at a small slip angle.
once past this peak, the tire has no grip and the car spins around.
Altering your Pacejka curve so it looks similar to mine above should help prevent this and allow for drifting.

You should be able to get variable car handling from using different curves. The Racer sim for instance uses different coefficients for front and rear tires.

But specifically for my game, i just rotate the cars velocity vector by the lateral Pacejka force to give that arcade drifting feel.

It's not physically accurate in any way and i did have to tune various attributes to get the correct feel i was after.

In theory, a physically accurate sim should be able to produce a wide range of handling for a car from an arcade drift feel to a simulation mode, by altering such things as the Pacejka curves, engine power, gear ratio's ect.

But in practice creating an accurate sim is going take a long time to do (particularly because theres very little information available on the subject), so it comes down to priorities.

If your priorities are to get an arcade game written as quickly as possible then i see no reason in hacking together an arcade sim, which is exactly what i did for my game.

If on the other hand you want to write a physically accurate sim and then use that as a basis for games, then it will take a long time to get right.
You could use a third party car physics engine and i know some general purpose physics engines support wheel physics and suspension constraints (Newton physics engine for example) , so that may be an easier route for you.

#3K_J_M

Posted 13 September 2012 - 04:28 PM

Hi.

For my Autocross Racing game i used lateral Pacejka coeficients similar to this curve.

Posted Image


This gives a very forgiving tire with a lot of grip at all slip angles.

I noticed in your second video that your car reaches a maximum slip angle before it loses grip and spins around.
This is classic of a Pacejka curve that peaks at a small slip angle.
once past this peak, the tire has no grip and the car spins around.
Altering your Pacejka curve so it looks similar to mine above should help prevent this and allow for drifting.

You should be able to get variable car handling from using different curves. The Racer sim for instance uses different coefficients for front and rear tires.

But specifically for my game, i just rotate the cars velocity vector by the lateral Pacejka force to give that arcade drifting feel.

It's not physicaly accurate in any way, but i did have to tune the handling to get the correct feel i was after.

In theory, a physically accurate sim should be able to produce a wide range of handling for a car from an arcade drift feel to a simulation mode, by altering such things as the Pacejka curves, engine power, gear ratio's ect.

But in practice creating that accurate sim is going take a long time to do (particularly because theres very little information available on the subject), so it comes down to priorities.

If your priorities are to get an arcade game written as quickly as possible then i see no reason in hacking together an arcade sim, which is exactly what i did for my game.

If on the other hand you want to write a physically accurate sim and then use that as a basis for games, then it will take a long time to get right.
You could use a third party car physics engine and i know some general purpose physics engines support wheel physics and suspension constraints (Newton physics engine for example) , so that may be an easier route for you.

#2K_J_M

Posted 13 September 2012 - 04:22 PM

Hi.

For my Autocross Racing game i used lateral Pacejka coeficients similar to this curve.

Posted Image


This gives a very forgiving tire with a lot of grip at all slip angles.

You should be able to get variable car handling from using different curves. The Racer sim for instance uses different coefficients for front and rear tires.

But specifically for my game, i just rotate the cars velocity vector by the lateral Pacejka force to give that arcade drifting feel.

It's not physicaly accurate in any way, but i did have to tune the handling to get the correct feel i was after.

In theory, a physically accurate sim should be able to produce a wide range of handling for a car from an arcade drift feel to a simulation mode, by altering such things as the Pacejka curves, engine power, gear ratio's ect.

But in practice creating that accurate sim is going take a long time to do (particularly because theres very little information available on the subject), so it comes down to priorities.

If your priorities are to get an arcade game written as quickly as possible then i see no reason in hacking together an arcade sim, which is exactly what i did for my game.

If on the other hand you want to write a physically accurate sim and then use that as a basis for games, then it will take a long time to get right.
You could use a third party car physics engine and i know some general purpose physics engines support wheel physics and suspension constraints (Newton physics engine for example) , so that may be an easier route for you.

#1K_J_M

Posted 13 September 2012 - 04:19 PM

Hi.

For my Autocross Racing game i used lateral Pacejka coeficients similar to this curve.

Posted Image


This gives a very forgiving tire with a lot of grip at all slip angles.

You should be able to get variable car handling from using different curves. The Racer sim for instance uses different coefficients for front and rear tires.

But specifically for my game, i just rotate the cars velocity vector by the lateral Pacejka force to give that arcade drifting feel.

It's not physicaly accurate in any way, but i did have to tune the handling to get the correct feel i was after.

In theory, a physically accurate sim should be able to produce a wide range of handling for a car from an arcade drift feel to a simulation mode, by altering such things as the Pacejka curves, engine power, gear ratio's ect.

But in practice creating that accurate sim is going take a long time to do (particularly because theres very little information available on the subject), so it comes down to priorities.

If your priorities are to get an arcade game written as quickly as possible then i see no reason in hacking together an arcade sim, which is exactly what i did for my game.

If on the other hand you want to write a physically accurate sim and then use that as a basis for games, then it will take a long time to get right.
You could use a third party car phsyics engine and i know some general purpose physics engines support wheel physics and suspension constraints (Newton physics engine for example) , so that may be an easier route for you.

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