This exercise will help you to understand why we use the different function curves.

 

1. With the Top View selected, using The Keyboard Entry function, create a sphere: radius 30
2. In the Front Viewport: Change the Pivot Point of the sphere so that it’s situated at the bottom of the sphere in the centre:  Heirarchy>Affect Pivot Only>Move transform type in: Y= -30

3. Un-Check Affect Pivot Only, and using the Transform Type In, move the sphere 30 in the Y Direction. The bottom of your sphere should now be resting on the horizontal Origin Axis.

4. We now need to Set-up the Time configuration for our animation. Click the Time Configuration button located in the Animation Controls.
5. This brings up the Time Configuration window. Set the Animation length to 30 frames. Change the Frame Rate to PAL.  Click OK.
6. Right Click your Sphere and choose Properties. In the Properties Dialog box, check the Trajectory check-box. This will enable you to see the path of your sphere once we animate it.
7. Zoom out the Front view and pan so that your sphere is situated at the bottom of the view:

8. Turn on the Animate button. Move the Time Slider to Frame 15.
9. Move your sphere to the top of the front viewport (Make sure you constrain to the Y direction).

10. Turn off the Animate Button.
11.  We now have two key frames. One at frame 0, and one at frame 15. Swap the positions of these key frames. You can do this by dragging them in the timeline. Our sphere now begins at the top of the viewport at frame 0, and moves down to the bottom of the viewport at frame 15.
12. In order to complete the bounce, we need the sphere to return to its original position at frame 30. To do this, simply copy the Keyframe from frame 0 to frame 30. You can do this by Shift-Clicking the Keyframe and dragging to frame 30.
13. Play your animation. Does it look like a bouncing ball?
14. Pan your Front view so that your ball animation is at the left hand side of the view:

15.  Now create 4 copies of your sphere: with the movement constrained to the X axis, in the front view, Shift-Click and drag your sphere to the right:

16. In the clone options dialog box, choose Copy, and choose 4 as the number of copies. You should end up with something like this:

17. Click zoom extents to centre the spheres in the view.
18. Save your Project now, so that if you get all confused, you can come back to this stage.
19. Select Sphere02 and open Trackview. Apply a Position XYZ Controller to the Position track for Sphere02:

        ------        ------  

19. Change the TrackView View type to Function Curves:
20.  Delete the Flat Curves in the X and Y tracks by selecting and deleting the key frames.
21. In the Z Position Track, look at the Curve and compare it with the movement of your Sphere.
22. Try changing the Tangent Types of the 3 key frames and see how this affects your animation.
23. Repeat steps 19 – 22 for each of your spheres. Each time, choose a different tangent type or combination of tangent types for the key frames. You can leave your animation playing whilst you do this to see interactively how the spheres behave differently. (If your computer slows down to much to do this, try the exercise with just 3 Spheres).
24. See if you can find the best combination of tangent types to make the ball look like it’s actually bouncing.

The Different Tangent Types are:

	Smooth
	Linear
	Step
	Fast
	Slow
	Custom

Refer to Lecture 6-Page 4 for more info on what the different tangent types do.

Try to figure out the best combination for yourself before going on to the next page. If you have a ball handy, bounce it! Watch how it behaves in between the 3 stages of the bounce i.e. top/bottom/top. Try to apply this to your Curve.