[ODE] bouncy car

[Megan Fox]

It is not uncommon for people to model their cars as single boxes, not
even using true wheels (cast rays straight down at each of the four
corners, roll your own springy suspension code, place the tires
accordingly along the ray, etc), depending on the number of cars
you'll want in a sim and the sort of handling you want.

Especially in a case like that, how you're going to go about applying
your wind resistance/downforce/upforce/etc is limited only by your own
imagination.  From previous discussions, people have found applying a
down force to greatly help with stability (with some kooky black magic
involving how many tires are touching ground to make sure you're not
accelerating your car into space with this down force when it's in the
process of rolling), as well as making sure to place your center of
mass at the lower edge of the car's box body (that is, translate your
box geom up the Y axis by boxheight/2 relative to the center of the
car, via an nGeomTransform).


You're definately going to want to do a bit of searching of the
archives, there have been quite a few excellent discussions on making
stable cars (all the way from ultra-realistic sim to
good/solid-feeling arcade sim).

-Megan Fox

> yes.  which is not ideal if the car is going up a hill!!
> 
> i want to be able to apply windspeed force to the *sides* of
> the car body.
> 
> not sure what i'm going to do about the underside though -
> heck i may just assume perfect aerodynamics and apply a
> force anyway, which will, if the car is tipped nose-forward
> (arse in air and still going forwards) be applied downwards
> and backwards.