Visual QuickStart Guide [Electronic resources] : Final Cut Express HD for Mac OS X نسخه متنی

Animating Clip Motion with Keyframes

The previous section explained how to use motion properties to alter a clip's shape, size, and transparency in a static composition. In this section, you'll finally learn how to use motion properties to actually move clips around.

Working with basic motion keyframe commands

The best place to use motion keyframes to animate a motion path is either the Canvas or the Viewer when it is in Image+Wireframe modeall the operations described in this section are performed in Wireframe mode.

You can work with motion keyframes in both the Canvas and the Viewer, but because keyframing more commonly happens in the Canvas, the directions in this section mention only the Canvas.

To set a motion keyframe:

Tip

Clicking the Add Motion Keyframe button in the Canvas sets a motion keyframe across all motion parameters for the current frame.

To navigate between motion keyframes:

Tip

Toggle the Auto Select control off for any track you want to exclude from your keyframe review. FCE will ignore the keyframes on that track.

To delete a motion keyframe:

In the Canvas wireframe overlay,

do one of the following:

Figure 15.37 ).



Figure 15.37. To delete the keyframe, Control-click it and choose Delete Point from the shortcut menu.







• Option-click the keyframe with the Selection tool or the Pen tool (Figure 15.38 ).
  
  

  Figure 15.38. Another way to delete a motion keyframe is to Option-click it with the Selection tool or the Pen tool.

  
  

  
  




To delete all keyframes:

• On the clip's Motion tab, click the Reset button to delete all keyframes for that parameter and return the parameter to its original setting (Figure 15.39 ).

  
  

  Figure 15.39. Click the Reset button next to a motion property on the clip's Motion tab to delete all keyframes for that motion property.

  
  

  
  




To refine a motion keyframe:




1.	Control-click the keyframe and choose Ease In/Ease Out from the shortcut menu (Figure 15.40 ). Figure 15.40. To smooth a corner type keyframe to a Bézier curve type, Control-click the keyframe and choose Ease In/Ease Out from the shortcut menu. The keyframe changes into a curve type, and Bézier handles appear.
2.	Drag the small blue circle at the end of the Bézier handle to adjust the motion path leading up to (or away from) the keyframe (Figure 15.41 ). Figure 15.41. Drag the small blue circle at the end of the Bézier handle to adjust the motion path leading away from the keyframe.




Tip

Refine opacity and audio level overlay keyframes in the Timeline by Control-clicking the overlay keyframe and selecting Smooth from the shortcut menu.

To move a motion keyframe:

• In the Canvas wireframe overlay, click the motion keyframe with the appropriate selection tool and drag it to a new location.





Setting motion keyframes with timecode entry




Evenly spaced keyframes are essential for smooth, even changes in your effects and for precision synchronization to music or other effects. This is especially true for motion effects. When you animate a program element, using timecode ensures that your keyframes will be set at precise intervals. This task shows you how to rotate a clip using timecode entry to set keyframes.

To set keyframes using timecode entry:




1.	In the Timeline, double-click the clip you want to rotate to open it in the Viewer.
2.	In the Viewer, click the Motion tab; then press the Home key to jump the playhead to the first frame of your clip.
3.	In the Canvas, click the Add Keyframe button (Figure 15.42 ); or press Control-K. Figure 15.42. To add the first keyframe, click the Add Keyframe button on the Canvas. The clip's first Rotation keyframe is set on the first frame.
4.	Verify that the Rotation control is set to zero. This establishes the clip's orientation at the beginning of the rotation.
5.	Click the Current Timecode field at the bottom left of the Motion tab; then type +30 to move the playhead 30 frames forward (Figure 15.43 ). Figure 15.43. Click the Current Timecode field at the bottom left of the Motion tab; then type +30 to add 30 frames to the playhead location. The playhead advances 30 frames.
6.	Click the Add Keyframe button again; then do one of the following: In the Rotation control dial, drag the needle clockwise to set the keyframe value to 180 (Figure 15.44 ). Figure 15.44. Set the keyframe value to 180 by dragging the Rotation dial needle to the right. Enter 180 in the Rotation text field.
7.	Repeat steps 5 and 6, increasing the Rotation value to 360. You have set three keyframes, exactly 30 frames apart, causing your clip to complete one full 360-degree rotation in 2 seconds (Figure 15.45 ). Figure 15.45. You have set three keyframes, exactly 30 frames apart, that program your clip to complete one full 360-degree rotation in 2 seconds.
8.	Press Option-K to step backward through your three keyframes, noting that the clip flips and the Rotation value updates at each keyframe. Press Shift-K to step forward through the keyframes.
9.	You must render your rotating clip before you can play it back. Select the clip; then choose Sequence > Render Selection.
10.	Play back your rotation effect.




Tip

Strictly speaking, it's not necessary to click the Add Keyframe button to set the second and third keyframes; you need only change the keyframe's value on the Motion tab. However, rotation keyframes don't show up in the wireframe overlay even when they are present. Pressing the Add Keyframe button sets a keyframe across all motion parameters, so the green highlighting is visible.