Analysis/Evaluate, measure, measure curve used to make helix, make a straight tube the measured length. Pro/E 2001 does not have such a command, but if you do and use the math, it can go either way. Someone else asked me the same question today?
Sidenote: Pro/E can create any curve bye equation. The equation for the helix can come from the line distance + a variable.
Warp is a good tool but if your end result is a true helix, then it would probably be best to create it using a helical sweep, or formed curve on a surface or any of the other myriad options for generating a helix. Curve by equation being an obvious one.
I know but after much trying I was unable to use helical sweep etc for making something like this into a helix. So I have resorted to approximate methods using warp. All I know is the pitch and amplitude required so I am just using the measure tool to approximate.