Lesson 07 - Expressions and Time Games
Spring 2011 - part of the Final Exam study guide.

1. Solving the problem of JERKY MOTION that occurs after you STRETCH footage. Book example STRETCHES footage to 300% so it lasts 30 seconds and 3 frames instead of 10 seconds and 01 frame.

   The icon that looks like a film strip is in the middle of the Switches column below. It is right after the fx icon (for turning all effects (if there are any) on or off for a layer). It is just to the left of the switch for enabling Motion Blur for the layer.

2. MASTER FRAME BLENDING SWITCH: The master switch on top "Enables Frame Blending for all layers with the Frame Blend Switch set". It is immediately to the left of the master switch that "Enables Motion Blur for all layers with the Motion Blur switch set".
3. See the JPG snapshot above here. The above Frame Blending switch with the dotted line proceeding from the upper left corner to the lower right corner is the setting for BASIC FRAME BLENDING. Basic Frame Blending is sometimes NOT a good solution for certain footage that has been stretched. To quote the book:

   "Normal frame blending creates visible ghosting along sharp edges as it crossfades between layers."

   "Stop the preview and press PageDown to step through the frames, and you will see echoes around sharp edges such as his jacket. Frame blending just mixes together adjacent frames; you ca obviously see this crossfading effect on sharp footage."

   
4. The Solid Forward Leaning slash indicates the Frame Blending switch has been set here. This is an enhanced mode of frame blending and is known as: PIXEL MOTION. The ghosts disappear (oh, Ghostbusters movie reference!). New in-between frames are created instead of blending and crossfading the original frames of the STRETCHED footage.

   "This enhanced frame blending mode is known as Pixel Motion. The ghosts will disappear. Pixel Motion studies the movement of every pixel between frames and calculates here each pixel should be to create a new in-between frame at the requested time."

   "RAM Preview; it takes looooooooooooooooonger because Pixel Motion requires a lot of computing power."

   "Clicking a layer's Frame Blend switch a second time changes it to a slash, which engages Pixel Motion. The creates brand new in-between frames, resulting in cleaner images."

   
5. Master Frame Blending switch to enable it for ALL LAYERS with frame blending switch set to either BASIC FRAME BLENDING or PIXEL MOTION frame blending. Helpful ways to remember these terms - FB = Frame Blending = Facebook. PM = after noon = Pixel Motion.

6. Going for a Loop - pages 176-177 of Lesson 07. loopOut("pingpong"), loopOut("cycle") and loopOut("offset"). Which one of these three was used earlier in modeling a flying 3D bird and its wings flapping up and down? The "pingpong" approach might work best for warming the hands around the fire animation of the UNI Interlude dance to Attack Attack.

   For loopOut(), the last KF (KeyFrame) on the layer with the loopOut() expression must be BEFORE the very lat frame on the timeline. Why? Think about why it would make no sense otherwise.

7. 14-Time Remap*Started example from Lesson 07. Don't cry over spilled milk.
   Layer menu > Time > Enable Time Remapping command. What does it do?

   How can you make time footage go in reverse using TIME REMAPPING? Suppose we wanted to have frame 91 to frame 150 play and then go in reverse playing frame 150, 149, 148, 147, ... to frame 93, 92, 91. How would you do that? Recall the milk example from page 187 of the textbook.

   How can you speed up or slow down footage?

   What is the best way to Insert a new KF (Keyframe) into a layers Time Remap property?

   "In After Effects, you can keyframe almost anything - including time itself. The door to this world is Time Remapping. This parameter allows you to define which frame of a source should be playing at a specific frame of your comp. After Effects will the speed up or slow dow the footage as needed between keyframes to make this happen."