rec.autos.simulators

  Huh?  Wha??  ??  GREGOR!!!  You came up with this, didn't you!?  How???

  I'll take your word for it anyway 'cause I know it works, but my brain tells
me you can't use the answer to the equation in the equation itself to find the
answer to the equation...  How in the world can use use v' in the equation
you're using to find v' ??  

  Solving for it gives this as you said (I DO NOT know how to solve this one
myself, thank you):  

  So, v' is the future velocity, right?  This equation then would be like this
in the other notation you used, right?:

  v' = (v' + RR_TIMESTEP*forceNonDamper.y / Mass) / (1+ forceDamper / Mass)

  That's crazy...  Can someone explain how/why this can be done to a
far-from-math-genious?  My IQ just dropped 20% and now equals my shoe size...
Somebody educate me here!

  As Yellow would say, "Oooooooh yeah."  Good luck, send pictures of your prize
wearing nothing but a race helmet too :0)

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://www.racesimcentral.net/

My little car sim screenshots:
http://www.racesimcentral.net/

<beavis>

heuh Heuh - he said helmet <g>

</beavis>

<butthead>
  ehhhh...  Shut--up.. Beavis..  eh-hehe.. Uhhhh huh..  That was cool...
Eeee-huh huh... huh.  
</butthead>

<beavis>
Yeah!  Hehehehe--  Yeah! Yeah!  Hey Butthead!  I think he's gonna score!  Yeah!
 Cool!  Hehehe! HeheheheyaAAAAA!!  
</beavis>

<SMACK!>

:0P

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com

My little car sim screenshots:
http://performancesimulations.com/scnshot4.htm

Nah, I didn't come up with that, I think it was Baraff and his implicit
integration stuff. Anyway, as you say the above equation doesn't give
you an explicit solution for v' as v' is also on the right hand side.
This is why it's called implicit integration :). If you however reorder
the terms so that you leave only v' on one side (solve for v'), you may
get it explicitly but now the equation is a bit more involved, as you
can see later.

Anyway, the idea is that you don't know the average force on the damper
well if your damping happens very fast within your time interval (as is
the case with the wheel-damper system). The proper way would be knowing
the average value of the damper force in this timestep. In the explicit
scheme, you only use the value of the damper force at the beginning of
the interval, while in the new implicit scheme you get it only at the
end of this time interval, with the added bonus of high stability of
calculation. You may also try with averages of these two values (i.e.
(v+v')/2 instead of only v or v' on the right hand side) or any other
combinations, I haven't realy tried to play with that. If you do, let us
know how it works :).

Greetings,

-Gregor

Still, you suggested the above method to me. Works great for Cart cars
and such. :)

It's in my code, so I could try it, but I like the stable one. :)
I'll add it to the Racer v2.0 section, lol.

Ruud van Gaal
Free car sim  : http://www.marketgraph.nl/gallery/racer/
Pencil art    : http://www.marketgraph.nl/gallery/