RE: [CAD_CAM_EDM_DRO] Math for constant speed ellipse

> I think I have some bad news if you expect to get f(t) in open
> algebraic form. The total circumference of an ellipse cannot be
> calculated in algebraic form because it involves the Elliptic
> integral of the second kind [E(k, phi) where k is related to the
> eccentricity and phi is the angle about the center of the ellipse],
> which can only be evaluated using an infinite series (or a suitable
> initial subset of terms giving sufficient accuracy) or by table lookup.

Eeek, I had no idea.

> I therefore find it doubtful that the length of a segment of an
> ellipse could be represented in open form, and the same goes for
> anything involving the speed of motion along an ellipse.

Sounds reasonable given the above. :(

> Doesn't mean it is impossible though, just unlikely.
> -Kevin Martin

Out of curiousity, is this related to eliptic cryptography? If so, then a
solution to my problem might be bad news to security people.

Todd Fleming