I can't place a planenormal to the end of my helix in order to create a spring. I'mgetting an error message that says "A vertex was not found on theselected curve; no construction plane is created". In the Planedialog box I've selected "Normal to Curve", and I've selected thehelix for the reference entity. Any ideas on what I'm doingwrong?

I'm able to performthis operation readily on a spline or other types oflines.

 

XP x64, SW 2007SP4.0