- The surface is specified in the control window.
- A green line in the "Domain" window is selcted using a hotspot to
choose a point on the line, and changing alpha in the control window
changes the angle of the line.
- This image of this line is displayed in the "Darboux Frame"
window in green. The image of the hotspot is a white sphere.
- The tangent vector T is displayed in red. The normal vector
N is displayed in blue. The U vector is displayed in magenta.
- The geodesic curvature along the image curve is displayed in
orange in the "Kg(t)" window.
- The geodesic torsion along the image curve is displayed in cyan
in the "Tg(t)" window.
- Readouts in the control window give both the geodesic curvature
and torsion at the image of the hotspot.