Re: [isugamedev-devel] Car rotating physics

[Ben S. <bs...@vr...>]

ok, i think i may have an answer for you. you say you've got direction,
speed and rotation of the wheels relative to the direction the teapot is
driving. i was getting all turned around thinking about how to relate the
angle of rotation of the front wheels to the circular rotation of the car.
thankfully Car Physics for Games
(http://home.planet.nl/~monstrous/tutcar.html) pointed me in the right
direction.

it turns out that the angle of rotation of your front wheels is the same
as the angle at the center of the circle. Let's call that angle a. given
the distance between the centers of the rear wheel and the front wheel is
L, you can calcular the radius (R) of the circle you are turning around:

R = L / sin(a)

of course if the steering angle (a) is 0, the sin goes to zero
(undefined) - so we're traveling in a straight line.

from the radius (R) and your speed (s), you can get your rotations per
second (w) as

w = s / R

where the units of w is radians/sec

obviously, the web page i cited explains this much better with pretty
pictures as well. ^_^ i hope this gets that teapot racer ticking along.

cheers,
-----
Ben Scott
President ISU Game Developers Club
Treasurer ISU Ballroom Dance Company
bs...@ia...

On Fri, 8 Feb 2002, Andres Reinot wrote:

> I've almost incorporated ticks into my teapot, but now I've screwed up my fragile hack-n-slash pot turning equation.
> 
> Does anyone know real car turning physics?  I've got the direction, speed, and the rotation of the front wheels, what do I do with em? I need to know what is the rate of rotation of the pot...
> 
>