func (herm *T) Length(t float64) float64 {
	return Length(&herm.A.Point, &herm.A.Tangent, &herm.B.Point, &herm.B.Tangent, t)
}
Length returns the length of a hermit spline from A.Point to t (0,1).
package hermit
import (
	"fmt"
	"github.com/ungerik/go3d/float64/vec3"
)
type PointTangent struct {
	Point   vec3.T
	Tangent vec3.T
}
type T struct {
	A PointTangent
	B PointTangent
}
func Parse(s string) (r T, err error) {
	_, err = fmt.Sscan(s,
		&r.A.Point[0], &r.A.Point[1], &r.A.Point[2],
		&r.A.Tangent[0], &r.A.Tangent[1], &r.A.Tangent[2],
		&r.B.Point[0], &r.B.Point[1], &r.B.Point[2],
		&r.B.Tangent[0], &r.B.Tangent[1], &r.B.Tangent[2],
	)
	return r, err
}
func (herm *T) String() string {
	return fmt.Sprintf("%s %s %s %s",
		herm.A.Point.String(), herm.A.Tangent.String(),
		herm.B.Point.String(), herm.B.Tangent.String(),
	)
}
func (herm *T) Point(t float64) vec3.T {
	return Point(&herm.A.Point, &herm.A.Tangent, &herm.B.Point, &herm.B.Tangent, t)
}
func (herm *T) Tangent(t float64) vec3.T {
	return Tangent(&herm.A.Point, &herm.A.Tangent, &herm.B.Point, &herm.B.Tangent, t)
}