Apple Motion 4 - Manual (Page 537)

When Record is enabled, a keyframe is created for any parameter that is adjusted. This
includes parameters adjusted in the Canvas, Inspector, or HUD. In the Recording Options
dialog (choose Edit > Recording Options or press Option-A), you can select the “Record
keyframes on animated parameters only” option, which adds keyframes only to parameters
that are already animated (keyframed)—even when Record is enabled. For more
information, see
Recording Keyframes on Animated Parameters Only .
You can also use the HUD and the Inspector to set and modify values for nearly every
option in the application. Any time you adjust a slider or other control, you have the
option of locking that change to the current frame, thereby setting a keyframe. From that
point on, no matter what else you do, that parameter always finds its way to that specific
value when playback reaches that frame.
Keyframed Opacity
parameter
HUD displays current
value of animated
Opacity parameter
537 Chapter 10 Keyframes and Curves