See the file I attached above.
Never ever use the 3D sketch Helix - use Coil with line for surface instead.
Revolve open profile for revolved surface instead of solid.
Please mark this response as "Accept as Solution" if it answers your question.
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Autodesk Inventor 2013 Certified Professional
Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional
Inventor Professional 2013 SP 1.1 Edu 64-bit
GeForce GTX 560M i7-2670QM @ 2.2GHz 8GB RAM
http://home.pct.edu/~jmather/content/DSG322/inventor_surface_tutorials.htm
http://www.autodesk.com/edcommunity
Still waiting for -Draft option on any Rib feature.
