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

In this lesson, you will link the bouncing ball to a helper object. Then you can animate the helper so that the ball bounces across the top of some text. This animation technique is useful because you can control the ball’s bouncing and its traveling motion independently.

Set up the lesson:

  1. On the File menu choose Open.
  2. Navigate to the \tutorials\intro_to_animation directory on your hard disk and open bounce_dummy.max.

    This file is similar to the bouncing ball created in the last lesson. The only difference is that it has a text object prepared for you in the scene and it has a longer active time segment.

    TipIf you want to keep using your own bouncing ball, you can merge the text object in from the bounce_dummy.max file using File > Merge. Or create your own.
  3. If you didn't open bounce_dummy.max., you'll need to extend the active time segment to 240 frames. Click the Time Configuration button and then in the Animation group change End Time to 240.

Create a dummy object:

  1. Go to frame 0, if you're not there already.
  2. Right-click the Top viewport to activate it, then zoom in on the ball and the box.
  3. On the Create panel, click the helpers button, then on the Object Type rollout click Dummy.
  4. In the Top viewport, move the cursor over the ball.
    TipMove the Layers and Extras toolbars away from the Top viewport
  5. Press the mouse button and drag outwards to create a dummy object.

    Make the dummy in the Top viewport.

    If you look in the Front viewport, you'll see that while the ball is up in the air, the dummy is positioned at the same level as the box.

    Dummy created below the ball

    Next you will align the dummy so that it is centered over the sphere when viewed from the top.

  6. On the toolbar, click Align. Then in the Top viewport, click the Sphere.

    The Align Selection dialog is displayed.

  7. On the Align Selection dialog, turn on X Position and Y Position, but leave Z turned off. Click OK.

    You'll see the dummy shift position so it is aligned to the sphere.

    Next, you'll align the dummy's pivot point with its base, and you will position the dummy so that it sits on top of the box. The idea is to set up the dummy so that its pivot point will match where the ball bounces. Then placing the dummy on any frame in time will ensure the correct alignment.

  8. Select the dummy object, and go to the Hierarchy panel.

    Instead of moving the pivot, you will move the object using Affect Object Only. This moves the object but leaves the pivot unmoved.

  9. On the Adjust Pivot rollout, click Affect Object Only to turn it on.

    The pivot icon is displayed in the viewport.

    Pivot point tripod display

    Now you can move the object to change its relationship with the pivot point.

  10. Turn on Select And Move, and raise the dummy cube so its base is level with the pivot tripod. Use the Transform gizmo so the dummy only moves up.

    You don’t want to move in any other axis, since the dummy is already centered properly in the other axes.

    Tip You can increase the size of the transform gizmo by pressing the = key repeatedly until the gizmo is the size you want.

    = key used to grow the transform gizmo

  11. Turn off Affect Object Only.

    Now you will link the ball to the dummy. The dummy will become the parent to the bouncing ball.

Link the ball to the dummy:

  1. In the Front viewport, zoom in so you can see the dummy and the ball.
  2. On the main toolbar, turn on Select And Link.
  3. Move the cursor over the ball, then press and hold the mouse button.

    The cursor changes to two interlinked boxes.

  4. Move the mouse to the dummy. A rubber-band line follows the cursor. When the cursor passes over the dummy, it changes again. One box is white, showing you this object (the dummy) will be the parent of the first object (the ball). When the cursor has changed, release the mouse button.

    Link the ball to the dummy

    You just linked the ball to the dummy.

    You can also create linkages in Schematic View. For something this simple, it’s easier to link directly in the viewport.

    When you've created a linkage, it's a good idea to test it out to make sure you did what you think you did.

Verify that you've created the hierarchy:

  1. On the toolbar, turn on Select Object.
  2. Press H to select by object name.
  3. On the Select Objects dialog, turn on Display Subtree, it is isn't already on.

    The Sphere01 object should appear indented below Dummy01 in the list.

  4. Click Cancel to exit the Select Objects dialog.
  5. You can also test a linkage by transforming the parent object. Rotating the dummy in the viewport will affect he ball as well. If you do this, then undo the transform once you've tested your linkage.

    Testing the linkage

    Now you're ready to animate the dummy. You'll use simple Auto Key animation first, just so you can understand the process.

Animate the dummy:

  1. Grab the divider lines between the viewports and drag them so the perspective viewport is wide screen.
  2. Turn on Auto Key
  3. On the main toolbar, turn on Select And Move.
  4. At frame 0, move the dummy so it is to the left of the box in the Perspective viewport.

    Dummy at frame 0

  5. Use the time slider to move to frame 15, or type 15 in the Go To Frame field.
  6. Move the dummy using the Transform gizmo so the ball is touching the box.

    Dummy at frame 15

    You just set two keys for the dummy, one at the start location at frame 0 and a second at frame 15.

  7. Go to frame 30 and move the dummy again to the right of the box, so the ball continues to bounce away, rather than straight up in the air.

    Dummy at frame 30

    You've now set a third key at frame 30. If you play the animation, you'll see the ball bounce off the box as if it had been tossed.

    You can display the trajectory of the ball to help visualize the animation. Here's how.

  8. On the main toolbar, turn on Select Object.

    You can use any transform tool for this, but using Select Object ensures you don't accidentally transform the object.

  9. Select the ball, and then right-click it.
  10. Choose Properties from the quad menu.
  11. In the Object Properties dialog, in the Display Properties group, turn on Trajectory.

    Trajectory display for the ball

  12. Play the animation.

    You see the ball bouncing onto the box and off, following the trajectory.

Try Layout mode:

If you turn off Auto Key and move the dummy, you will be moving the entire animation in space. When both Auto Key and Set Key are off, you are working in what is known as Layout mode. Here you will use Layout mode, so that instead of the ball bouncing on the block, the ball bounces off the letter F.

  1. Turn off Auto Key Mode.

    The red disappears in the time slider background and viewport outline.

  2. Move the dummy object back toward the text.
  3. Watch the position of the trajectory and move the dummy until the bounce point of the trajectory intersects the top of the letter F.

    Layout Mode lets you move the animation in space.

Bounce the ball on the letters:

Now you'll repeat what you've learned to create the ball bouncing on the letters.

The ball bounces 8 times, making contact with the letters at frames 15, 45, 75, 105, 135, 165, 195, and 220.

  1. Turn on Auto Key.
  2. In the track bar, select the key at frame 30 and delete it.
  3. Move the time slider to frame 45 (or enter 45 in the Current Frame field).
  4. Position the dummy so the ball bounces on the double L's in the word “Follow”.
  5. Move the time slider, then the dummy so the ball bounces on the following letters at these frames.

  6. At frame 240, move the dummy so the ball move away from the letters.
  7. Play the animation and observe the results.
  8. Save your work as mybounce_text.max. If you had any trouble, you can open the file bounce_text.max to see the correct animation so far.

    Next you will learn to use a multiplier curve to affect the height of the bouncing ball.

Add a multiplier curve:

  1. Select the ball in the viewport, right-click and choose Curve Editor.

    The Curve Editor window is displayed, if it wasn't already visible.

  2. In the Controller window, click the Z Position track.
  3. On the Curves menu, choose Apply Multiplier Curve. In the Controller window, click the plus icon. Click the Multiplier Curve to highlight it, and then hold down Ctrl and click the Z Position track. This way you have only these two curves displayed.

    In the Controller window, the Multiplier curve is added beneath the Z position track. It's not very noticeable in the Keys window on the right.

    The scaling of the multiplier track is quite small, so the slightest change to a key could result in a large change in the animation. You can counteract this by zooming in on the multiplier track.

  4. On the Navigation: Track View toolbar (at the lower right of the Keys window), click the Zoom Region button. Drag a zoom region window around the key at frame 240 on the multiplier track.
  5. On the Settings menu, turn on Interactive Update.
  6. On the Track View toolbar click Move Keys to turn it on, then move the multiplier key downward, while observing the effect on the trajectory in the Perspective viewport.

    Lowering the multiplier curve shows effect on Z position curve in Keys window

    Don't move it below the horizontal zero value, or you will get some strange effects.

    Multiplier curve shown on trajectory

    TipYou can type in precision values on the Key Stats: Track View toolbar.

    While working with Multiplier curves, if you're not sure you like the results, you can just turn them off. Select the Multiplier curve in the Controller window, then on the Curves menu choose On/Off.

  7. Click Zoom Horizontal Extents on in the Navigation toolbar to see the entire curve again.

Next

Using the Dope Sheet Editor

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