I start with a 1 x 1 x 1 cube set at -9.5 Y units from the origin. I use an empty at the origin as my Center of Deformation. I use the simple deform modifier / Bend with 360 deg as the deform parameter. The resulting radius of the ring is about 10.159 and the diameter of the ring is about 20.318. Yes, I can scale the ring in X and Y back to the desired Diameter=20, and recenter the ring at the origin. But this introduces a slight error in the inside diameter of the ring that is a challenge to correct.
Is there any way to predict what this dimensional difference is before I begin and adjust for it in either the mesh center, cube size, Center of Deformation, or anything else that is predictable?
The Bend Deform is simple, but the outcome is imprecise. Is there a more precise way to construct the ring?