Equation of a rollercoaster looping?

[phildar]

hi all !
I try to make rollercoaster looping curve with no success… (try with vector2points)…
would you have any clue ?
thanks in advance !

https://thatsmaths.files.wordpress.com/2014/04/rollercoasterloops.png

[catweasel]

Have a look at the B-spline help patches, the 3d Wryly has a twisting loop that should be a good start

[phildar]

thanks !
here’s what I have so far. It would be nice to know this equation.
but my pratical patch does work too {:-)
spispispispispi.v4p (11.1 KB)