Create a curved circle with precise dimensions If you imagine the external edge of a torus, all the way around, or you imagine a uniform cylinder where you then bend the vertical edge in uniformly to create a circle - that is what I'm trying to achieve.  A curved circle with specific measurements.

Specifically, I want it to be 4 units high (easy) with the swell of the curve precisely one unit thick.  In other words, say the bottom of the curve is at 0.00, then the widest point of the swell is at 1.00 before coming back in again to 0.00 at the top of the curve.

I imagine this could be done by trimming down a torus, but the "exterior/interior" radii settings on the Torus Dimensions don't appear to be accurate enough for my purposes - because the Torus inner edge swells in too, and I can't therefore use that to measure because I don't know the degree of that swell.

I imagine this could be done by bending a 4-unit-high cylinder, but I don't know how to...

Any help/guidance much appreciated.

Thanks,
A
A curve with its control points precisely placed and a Screw modifier will do this.



Is this the shape you wanted?

Edit:

Sometimes the handles get swapped around, and that kinks the curve around on itself.  So move the handles around and see what effect that has on the curve to make sure they're coming out on the right sides.  If you move the control points (the handles get highlighted too) with G for grab, X, Y or Z for the axis and 0 or 1 or whatever you need, you can get them in a symmetrical place - you have control over that at least.  To get the handles arranged you can turn on Snap (the magnet icon at the bottom in Blender 2.79) and turn on Absolute Grid Alignment (the second icon along after Absolute Grid Alignment, you can move the handles to a fixed point on the grid so everything is properly aligned and symmetrical.  If you then want more or less curve you can move the handles to another grid point, keeping them symmetrical.