The Display & Tracing Options Window

The Display & Tracing Options Window provides a way to set various display and tracing options. As shown below, the window is divided into four parts. The first part is to indicate if the options should affect all curves or the current curve. The second part contains 11 display options. The third part provides a short cut for selecting the next curve or the previous curve to be the current curve. Finally, the four part is for closing this window. Clicking on these buttons activate or deactivate the select options. Options selected will be marked with a X. Some buttons are indented. This means those options are activated only if their "parent" options have been activated.

If you want the selected options applied to all curves on the drawing canvas, click on All Curves. Otherwise, the options will be applied to the current curve.

The display options include the following:

• Control Points
  If this option is activated, control points will be displayed. If w/ index is also activated, the control point indices (or IDs) will be shown.
• Tracing Point
  If this button is activated, the tracing point will be displayed. As the little triangle (i.e., the u-indicator) in the right-hand side of the vertical slider moves, its corresponding point, the tracing point, on the curve moves accordingly.
• Control Polygon
  If this button is activated, the control polygon will be shown.
• Convex Hull
  If this button is activated, the convex hull of the current u will be shown.
• de Casteljau's Alg./de Boor's Alg.
  When the current curve is a Bézier curve, this button shows de Casteljau's Alg.; otherwise, it shows de Boor's Alg.. If this button is activated, the de Casteljau or de Boor net will be shown. If w/ points is also activated, the endpoints of each segment will also be shown. See Tracing the Curve - de Casteljau's and de Boor's Algorithm for further details.
• Tangent, Binormal & Normal
  If this button is activated, the tangent vector, binormal vector and the normal vector at the tracing point (i.e., the moving triad) will be shown. If button Curvature Sphere is also activated, the curvature sphere at the tracing point will also be shown. Moreover, if Roller Coaster is activated, the Roller Coaster Window appears showing the roller coaster effect. Note that the curvature sphere and the roller coaster effect are independent of each other. See The Moving Triad, The Curvature Sphere, and The Roller Coaster Effect for further details about the moving triad, curvature sphere and roller coaster effect, respectively.
• Coordinate Axes
  If this button is activated, the coordinate axes will be shown in the drawing canvas.

Clicking Next Curve and Pre Curve selects the next curve and previous curve to be the current curve. If the current curve is the last (resp., first) curve, the next (resp., previous) curve is the first (resp., last) curve.

Finally, clicking on Dismiss closes this window.