UnwrapCurve for be sure of the length of your curves curvated
http://moi3d.com/forum/messages.php?webtag=MOI&msg=5136.1

or a simple click on curve gives the length also in the right corner page! ;)

Else a simple Network beteen 4 curves must make the trick! :)

Ok, thank you Pilou for the unwrap curve. I know now that i don't need the precision i'd ask. It is a twisted model with a false perspective.
Moujiik