Creating Animation Using Auto Key

Animating with Auto Key: Bouncing a Ball

Adding Parameter Curve Out-of-Range Types

 

Autodesk 3ds Max Tutorials > Animation Tutorials > Animating with Auto Key: Bouncing a Ball > 

Controlling In-Betweens

To make the ball bounce more convincingly, you'll change the interpolation on the key at frame 15.

You'll use the tangency handles available in the Curve Editor. The tangency of the curve will determine the position in space of the in-between frames. Ghosting will let you see where the in-betweens are being positioned.

Using ghosting to visualize in-betweens:

1. Move the time slider to frame 15.
2. From the Views menu, click Show Ghosting to turn on this feature.

   The ghosting feature shows object positions before the current keyframe in an aqua color.

3. Go to Customize menu > Preferences > Viewports tab, and set Ghosting Frames to 4 and set Display Nth frame to 3. Click OK to exit the dialog.

   The viewport displays the ghosting.

   

   Ghosting shows the object positions on previous keyframes.

4. Play the animation, and then stop.
5. Now, to control the in-betweens, right-click the ball in the viewport and choose Curve Editor.

   The Function Curve Editor is displayed across the top two viewports.

   The Curve Editor is composed of two windows, a Controller window on the left that shows the names of tracks, and a Keys window on the right that shows keys and curves.

6. In the Controller window on the left, click to select only the Z position track.
   NoteIf you don't see the Z Position track, click the plus icon to the left of the Sphere to expand the Sphere’s tracks. If you don’t see a plus icon, right-click and choose Manual Navigation, hold down Alt and right-click, and then choose Expand from the quad menu.

   There are a lot of possible configurations in the Curve Editor, so you may encounter variations from the standard.

   Now the only curve displayed in the Keys window is the one you want to work on.

   

   Function curve for bouncing ball Z position

7. Move the Track View time slider (the double aqua line in the Key window).

   As you move back and forth the animation plays in the viewport.

   If you look carefully you'll see a dark dot on the curve at frame 15.

8. Drag around the dark dot (the position key) to select it.

   The selected key turns white on the curve.

   To manipulate the curve you need to change the tangency type so you have access to tangency handles.

9. On the Track View toolbar, click Set Tangents To Custom.

   If you look carefully you'll see a pair of black tangency handles have appeared on the curve.

10. Hold down the Shift key and drag the left handle on the left upwards in the Key window.

    Using the Shift key lets you manipulate the left handle independently from the right.

    The curve now looks like this:

    

    Shift key allows for manipulation of individual handles.

    You'll change one more setting to make this tool more useful.

Using Interactive Update:

1. On the Track View Settings menu turn on Interactive Update. Now move the time slider to frame 15, then manipulate the tangency handle while observing the effect in the ghosting. You can clearly see the changes as you work.
2. Set the tangency handle so the in-betweens are mostly drawn toward the raised position (see the illustration that follows). With interactive update on you can do this with very fine control.

   

   Interactive update and ghosting

3. Move the time slider to frame 30, then adjust the right tangency handle so it approximately matches the left one.

   

   By manipulating this handle you can get different effects. The upward movement of the ball as it bounces off the table will determine the perception of the weight of the ball. The ball will appear to be bouncy, like a tennis ball, if the two handles are similar. The ball will appear to hang in space if enough of the in-betweens are drawn close to the topmost position.

4. Turn off Views > Show Ghosting and then play the animation. Concentrate on the movement of the ball. Adjust the curve handles some more while the animation plays. Observe the effect.

   The ball leaves the table as quickly as it hit it, then begins to slow down as it rises.

5. Play the animation, and then stop.

   The ball has bounce now. It looks like there is gravity at work here.

   When you see something you like in the viewport, it's a reminder that you should save your work. It's easy to forget while you're being creative.

6. Save your work as mybounce.max.

You've made the ball bounce once. In the next section you'll learn to repeat the bouncing of the ball using Out-of-Range types in Track View.