I have viewed the Equation Curve tutorials, and they show the Equation Curve command Icon in the Sketch ribbon, in the Draw area, just above the Spline command icon. I do not have such an icon, and cannot find it in the "Customize User Commands..." window either.
I am using Inventor 2012 Professional SP2.
Any ideas why the command icon is absent ?
Thanks,
Jim
Check the What's New for 2012 and 2013.
Maybe it wasn't there in 2012.
I see it as #15 here under Sketch http://blogs.rand.com/manufacturing/2012/03/inventor-2013-product-announcement-new-features.html
In earlier releases you could do the equation in Excel and then import the points into a sketch (and select the option to create a Spline on import).