"Ruben" > wrote in message
om...
> Gregor Veble > wrote in message
> >...
>
>> If you ever tried to ballance any four legged table you should know
>> that
>> its legs NEVER carry the same ammount of weight, no matter what stuff
>> you try to squeeze underneath the leg hanging in the air
>
> Unless the table is on carpet! Mine is on carpet, which makes it look
> as though all legs are carrying equal weight. But, I suppose this is a
> bit like having suspension.
>
> Yes, I see now - a proper model of suspension is what is needed to
> model weight transfer - only, this is a fair bit more complicated than
> I anticipated. It seems to me that the chassis must actually be able
> to pitch and roll which means that the suspension is not fixed at 90
> degrees to the chassis. Is this right?
>
> In any case, I am not going to try to model this for now. It's for a
> 2d game - so all that detail would be wasted. But isn't there an
> aproximate way of working out weight transfer from the tyre forces? On
> the other hand, perhaps it's not worth doing at all if not done
> properly..

In cases of rigid structure, you have to model the stiffnesses and
geometry of the 4 contact points to determine the loads in the 4
members. For car tires with suspension, you can ignore this and
calculate the load distribution from a simple freebody if you know the
location of the center of mass or better still, the mass distribution.
For table legs , there will be a certain amount of loading and
deflection in 3 of the members before the 4th is loaded, if at all.
Plastic deformation (the carpet) will reduce the problem to a simple
freebody similar to car tires.

PH