[ODE] Re: Simpler Suspension Geometries

[Billy Zelsnack]

> Havok (and Ipion which have merged) do have two optimized solutions for
> simulating vehicles and these are built on top of the physics engine,
> and indeed as Russell already states:
>
> 0) a special wheel constraint and 1) a raycast solution (one rigidbody
with
> tweaking
> parameters).

the raycasting solution (actually sphere casting) was my first thought
before i even started with constraints. my brother had used it successfully
a long time ago, but with point masses for a car instead of a rigidbody. his
stuff was all force based and i can't stand dealing with forces. they are
ucky. so i implemented mine rigidbody style and had a car rolling around
with spherical wheels, which worked well except for a lurching everytime you
would accelerate. i figured it was a tuning problem and being the research
geek i am, went onto messing with constraints. once i had the constraints
working, the car just plain worked. no tweaking. i was even using the same
spring strengths and damping values for the shocks from before. now i think
the lurching was from an implementation detail i was missing somewhere.

now that i have constraints working enough to satisfy my tech urges, i am
going to go back and not use them at all (for suspension). i'll try again
with raycasting.

do the vehicle demos on the havok site actually use the raycasting version?
anyone know of an actual example of a game that uses it? i would like an
example to strive to instead of working at blind target.

russ, are there plans on providing a less sophisticated vehicle model in
ode, or are you happy with the speed your hinge2 provides?

-billy




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