"J. Diehl" <j.d### [at] firemailde> wrote in
news:web.3d6e0f83a31ba4aaf70c33440@news.povray.org: 

> If you are looking for a physically realistic solution, you started at
> the wrong way at all - a Truck will never follow a spline. The rear
> axis never follows the front (steering) wheels. Think of a long
> vehicle turning sharp around a corner - while the front will pass it,
> the back will cut the edge! All I want to say is that you can't expect
> a physically right simulation of your trailer with any mathematic
> model, while your truck doesn't follow physics at all!
> But even if you can fix this - for a full phyisical simulaton you will
> need a more detailed mathematical and physical description of truck
> and trailer. The center of gravity will play a role as much as the
> mass of the trailer, the speed of all components and even the friction
> of the ground. Think of movements with high speed, on ice or in empty
> space! 

I don't think I said that I was looking for a completly correct physical 
model. The things I want to model are not physical correct anyway (the 
trucks can't steer for instance)

> But lets do a simpler model - at first for the simplest
> trailer-system: a two-wheeled trailer pulled by hand.
> Build a pole - a triangle, where (A) is the left wheel, (B) the right
> and (C) the coupling in your hand. So (AB) is the axis and (M) shall
> be the middle of the axis (AB). Then lets pull the coupling (C) to any
> new position (P) in the easiest way we coul describe and without
> hurting physics:
> 1. turn the trailer around (M) towards (P) so that the trailer is
> 'looking' at (P) (the axis (AB) is orthogonal to the direction (MP))
> 2. move the trailer straight along (MP) until (C) is at (P)

I came up with something quite similar over the last few days, but slighty 
diferent due to the fact that my implementation is different ofcourse.
 
> What do you think about this model?


Looks promising!!! 

I had a look at your VB code but to be honest I don't quite understand it, 
but I will try and implement something this weekend and with a bit of luck 
I can show an animation somewhere in the near future. I also downloaded 
your PDF file. It looks great!

Thanks!!!!

Thomas

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