# CG Lecture 31, Mon 2016-11-28

- Iclicker questions.
- If anyone wants to show the video to the class of Monday instead of Thurs, could you please write Shama (even if you filled out the LMS survey).
- Handwritten notes from
- There are many interactive spline demos on the web. Bayreuth is good. Try the following:
- Moving a control point moves only a few segments.
- If you make control points coincide then the continuity at that joint falls.
- You can make the curve have a kink. At that point, there is still parametric continuity, but not geometric continuity. That is, \(dx/dt\) and \(dy/dt\) are continuous but \(dy/dx\) is not.

- ibiblio shows the problem with interpolating a high degree polynomial. The curve swings wildly and it's notintuitive.
- Khan Academy shows some code. See how it decides which control point you clicked on.
- Programs drawing the Utah teapot.
- 14_2 Designing parametric cubic curves.
- 14_3 Bezier and spline curves and surfaces.
- 14_4 Rendering curves and surfaces.
- 14_5 Rendering the teapot.
- You do not need to learn most of those slides. Later I'll summarize what you need.
- 15_1 Global rendering.
- 15_2 Ray tracing.
- 15_3 What's next?.