Adobe 25510629 - After Effects CS3 Professional, Руководство пользователя

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106 How to
These instructions refer specifically to setting the Offset Into Scene time for a VirtualTrak
effect, but the steps are essentially the same regardless of which layer a clip is on or what type
of virtual set is assigned.
1.
Create a session with a virtual set that has a VirtualTrak set and an input clip in which the
subject walks into frame.
The name of a VirtualTrak set is followed by “(Trak)”. An example of a VirtualTrak set
is the “Museum Intro (Trak)” set in the Virtual Sets\Museum library (from MSL1).
If you don’t have your own input clip handy, use “Suzy – Wide – Walk in Left”, which
is in C:\Program Files\Adobe\Adobe Ultra CS3\Content\Sample Clips\NTSC Sample
Clips.
2.
In the Output Preview Monitor, drag the preview slider to the time when you want the clip
to begin playing. For VirtualTrak effects, this is typically when the plane of the input clip
appears or at some time shortly thereafter. If you’ve already keyed the input clip, disable
the keyer so that you can see the plane appear.
3.
Click the Set button for the Offset Into Scene setting on the Input tab. This applies the
current framecount from the Output Preview Monitor to this field, delaying the playback
of the input clip until this point in the session.
4.
Reenable the keyer and play the session in the Output Preview Monitor again to assess the
timing of the subject’s appearance. If the timing isn’t correct, then you probably need to
trim the In point for the input clip as described in
“Trimming the In and Out Points in a
video clip” on page 104 . For example, in the “Suzy – Wide – Walk in Left” clip, the subject
doesn’t enter from the left until frame 17.
5.
If the subject’s position isn’t correct relative to the virtual set, then you must change the
position of the input. For more information, see
“Moving and scaling an input within the
layer plane: Input Offset controls” on page 95 .
NO
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If you want to try adjusting the timing for a VirtualTrak session using a clip that’s built into
Ultra, see the tutorial titled “Adjusting Timing on a VirtualTrak set shot” at
www.adobe.com/support/ultra .