Sweep along conical helix

[BOPdesigner]

In NX6, I have created a conical helix with a law curve function. Now I am struggling to sweep a line profile along the curve. I want to sweep the line (orange in attached screen capture) along the helix guide now. I need the line to remain in the X-Y plane and normal to the guide curve facing inward when looking at it along the axis of the helix. Tried sweep along guide and swept features but the line always seems to twist as it sweeps. Also, is there a way to vary the length of the section line as a function of t as it is swept?

 

[cowski]

For the 1st part of your question, use the vector direction option in the sweep command and choose the axis direction of the helix. This orientation option will keep the section from twisting.

 

[SDETERS]

I do not know if NX6 has this but look into varational sweep.