Re: [Algorithms] Nearest point on plane for 2D IK

[David K. <da...@ik...>]

> Hmmm ... surely what you want is to find the point on the line closest to
> the center of the sphere (easy to do) and then if that is less than R away
> from the center you have definite intersection, and proceed to compute the
> points at which the line intersects the sphere, and otherwise, you
> conveniently have a point which is in line with the nearest tangential point
> of the sphere, so you can easily find that tangential point.

Well, computing the point when the ray intersect with the sphere is not a big
deal.
The problem comes when the ray does not intersect:

 I am not looking for the closest surface point on the sphere then, but a point
that
can be described as follow:

- Take the plane defined with the ray and the center of the sphere.
- Rotate the ray around its origin and along the plane until it is tangent to
the sphere.
- Compute the tangetial point (easy).

That's what seems to me complicated and which needs to be very accurate.

Any idea?

Thanks.

David Kornmann.
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