[ODE] rope made of small bodies and hinges (+ slider to eliminate the stretching)

wesa aapro waapro at cc.hut.fi
Sun Feb 10 07:29:02 2002


> > any suggestions how to go round this problem? or is there a better way
to
> > implement rope?
>
> If there's tension on it, it will be pulled straight, right?  In that
> case, you could replace it with a single body, attached to each rocket
> with a ball joint.  When the tension gets small (pick a threshold, do some
> trial-and-error), then replace the single object with a chain of
> objects.  No promises, but it might work. :-)

thanks, that thought never occured to me!

i think this would be even better, since it doesnt need any logic:
i could attach a slider between the first and the last element of the rope
and set the hi-stop to ensure the rope would never stretch. but slider is
not good for this since it has fixed axis...
but, i could attach extra bodies to the end elements with hinges. and then
attach a slider between these extra bodies. the rotation of the hinges would
ensure that the extra bodies would be along the same axis. i guess this
would kill almost all of the stretching.

ok, and i had to try it and it works!  the rope still stretches a bit but i
guess i can live with that.

all of the strechting could be eliminated with a new kind of joint, so i
wouldnt need the hinges and the extra bodies...

so a question to russ:
any plans for implementing a joint that is combination of slider and ball
and socket? the idea would be to limit the distance between two bodies but
not on any specific axis? this could also be used to implement some sort of
gravity beam... or is it already possible in some other way?

wesa.