CAP 151 - Introduction to Computer Animation
Lesson 2 - Advanced Animation (part 1)
This lesson introduces more features of the After Effects interface. Objectives important to this lesson:
- Anchor Point
- Faux Motion (Ken Burns Effect)
- Graph Editor
- Motion paths
We begin this lesson by clarifying some concepts.
- Keyframes hold values for their layers at a moment on the timeline.
- Keyframes also hold interpolation values: the rate at which a value changes before and after the keyframe (velocity), and the smoothness or abruptness of the change into and out of the keyframe (influence).
- Keyframes can be temporal, showing a value changing over time, and they can be spatial, showing a change in position over time. This distinction is not really important, since we could also described a position change as a change in position value. The important difference described in the text is that spatial (position) keyframes have Bezier handles that allow you to modify the curve that flows into and out of the keyframe.
Tutorial Notes and Questions
Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.
Tutorial: Anchor Point 101
- Open the indicated project. Choose the indicated file from the Comps folder. Open the Sources folder, and find the second file. Learn the shortcut to add it to the current comp: Ctrl-/.
Use the mouse shortcut to open all the parameters: Alt-Click the arrow by the layer's name. (This did not work on my Windows computer. I had to open the Transform list manually.)
- The flower in this layer will be rotated and scaled, which presents a problem. The text explains that we would like it to scale from the bottom of its stem, as though it were growing. We would also like it to rotate on this point. It will do neither at the moment, because both animations use the Anchor Point as the motionless point from which they scale, and about which they rotate. The flower's Anchor Point is currently in its center. You will change that in a few steps. First, double-click the flower layer in the Timeline panel. This will open a view of the layer in a Layer panel. The Layer panel gives you a panel in which to modify a layer itself independently of the composition.
Move the panel as instructed so you can see the Layer panel and the Comp panel at the same time.
- Follow the instructions to access the Anchor Point Path property of the layer.
Move the Anchor Point in the Layer panel. Note, as the text explains, that the flower will move in the Comp panel. The text asks a question that it does not quite answer. You are not moving the flower. You are changing what part of the flower is attached to the anchor point. (Sorry, I'm tired of the pointless capitals.) The anchor point is staying in the same place in the Comp panel, so the flower moves in that panel as the anchor point is dragged/attached to a new part of the flower.
Think of the anchor point as a pin pushed through the middle of a picture, pinning the picture to the Comp panel. I want to move that pin to the bottom of the picture, but I can't pull the pin out of the Comp panel. The Layer panel lets the picture flow around the pin, so that the pin now goes through a different part of of the picture. In other words, you move the anchor point in the Layer panel, without moving it in the Comp panel. All motion is, after all, relative to your frame of reference.
- Since the flower is no longer located as desired in the Comp panel, fix it there.
- In case you didn't like the method above, the text shows you another way to move the anchor point.
Follow the instructions to turn on the Pan Behind tool. Using this tool, you can move the anchor point while in the Comp panel. Simpler?
- After moving the anchor point in the steps above, you had to move the layer (the flower) to the bottom side of the comp. This step gives you another way to do that.
If you right-click the Position value of the layer, you will be able to select Edit Value. Follow the instructions to set the position on the X and Y axes of the Comp panel.
The lesson continues with a technique that applies what some call the Ken Burns effect, zooming and panning on a still photo to give the illusion of animation. Watch some of the videos behind the link in the last sentence to get an idea of the value of this technique. It is not necessarily compelling in and of itself, but it is very effective when the narration accompanying the shot is about the feature that your zoom or pan is displaying.
Tutorial: Faux Motion Control
- Open the file indicated for this tutorial.
- Select the auto race layer and show its position and scale animations.
Question 1: What is the secret about showing a second or third transform line for a timeline layer that is not needed for the first one you show?
Question 2: The text tells you to enable keyframing for position and scale. It does not say how. How do you do that?
- When you drag the layer for the first keyframe, then reduce the scale, you lose focus on the cars you meant to show. The problem is the location and function of the anchor point again.
- The same problem occurs when you try to set the still for the last keyframe. (You are being told to do it this way to show how irritating it is.)
- Start a new (although, already named) comp as instructed. Add the auto race image to it.
This time show the scale and anchor point features as instructed. Note the instruction not to drag the layer in the Comp panel for the remainder of the exercise.
- Open the Layer panel for the auto race layer as instructed. Change magnification in this window so you can see all the cars. (Do this by using the dropdown in the lower left corner of the Layer panel. 33.3% will be about right.)
As instructed, set the view in the Layer panel to Anchor Point Path. (Ken Burns, here we come.)
It may be helpful to undock both the Layer panel and the Comp panel, so you can arrange them to see both better. (You can use the Workspace. Reset "Standard" command to put them back to normal later.)
Drag the anchor point in the Layer panel. You will find you are also panning in the Comp panel.
- Move the time indicator to the end of the timeline. Pan to a new car, and change the scale as instructed. You will find you are zooming in the Comp panel.
- Keyframing should have created a motion path automatically in the Layer panel. Since there are only a few points on it, use the Bezier handles as instructed to smooth out the path.
The next section of the lesson takes us to the Graph Editor, and introduces several useful commands. This is a good time to reset the workspace.
Tutorial: Graph Editor
- Open the dropdown in the upper left corner of the Comp panel to select Close All, as instructed in the text. Open the comp indicated in the text.
- Select the first layer in the layer stack, then press ctrl-a to select all layers. (It may not work if you don't select something in the timeline panel first. Press U to display all the properties that have been animated already.
You are also told to perform a RAM Preview of the current animation. The text informs you that the animation does not look right yet because your keyframes are all linear. (Linear keyframes are diamond shaped.) The "problem" with linear keyframes is that they change suddenly. This is like driving a car only by flooring the gas pedal and standing on the brake. That makes a rough ride. More finesse is desired. You will apply a more gentle touch next.
- Find and click the Graph Editor button. (It is illustrated on page 42 of the text.) Continue following the instructions in this step, The images on page 43 are meant to help. The top image is of the timeline panel when you start, the middle image is what you should see after making the change with the Eyeball button, and the third image is a blow up of the buttons at the bottom of the Graph Editor panel.
You should see a screen similar to the second picture on page 43. The graph lines are color coded for the kind of animation they represent. This does not appear to happen if the object has only one kind of animation. In this step, you learn that:
- pink stands for position
- red stands for x-scale, and green stands for y-scale
- turquoise stands for rotation (The text calls this color cyan.)
- blue stands for opacity
- Press F2 as instructed and all the lines disappear from the Graph Editor.
Question 3: Why are the lines all gone?
Open the Choose Graph Type and Options menu with the second button under the graph.
- Change the graph type to Edit Value Graph. This gets confusing, in that the pink line is now a red line and a green line. The good news is that if you hover over any of the lines, you get a popup that tells you what the line represents.
- Change the graph type to Edit Speed Graph. Note the explanation of the flat lines in this graph. A flat line means there is a constant rate of change. For example, the rotation of the snowflake is constant: it does not rotate faster or slower at any point, so the turquoise line is flat.
- Change the graph type again, this time to Auto-Select Graph Type. Now the red, blue, and turquoise lines represent changes in values for the various transforms. The value is shown on the vertical axis, and time is shown on the horizontal axis.
- Drag the keyframe for the cyan line that is located at 1:20.
Question 4: Which directions can you drag the keyframe to change its value?
- Drag the keyframe experimentally, as described.
Question 5: Which directions can you drag the keyframe to change when the rotation ends?
- This step shows the use of the Easy Ease In button to adjust the velocity and influence of the keyframe. It changes the slope of the line leading into the keyframe, making the rotation slow down before it stops. The line does not taper, its slope does, making it a curve. The line becomes more like a parabola. The keyframe changes by having a Bezier handle added, which lets you manually adjust the slope of the curve.
- Drag the Bezier handle to the left as suggested, to make the rotation slow down more gradually. Preview to check your work.
- This step addresses the final position of the snowflake. As a precaution, first press F2 to deselect all, then select the snowflake layer. You can shift-click the last keyframes for Position, Scale, and Opacity, or you can marquee select all three since they are clustered together. In the image below, I clicked one of them, then shift-clicked the other two. Oddly, when I marquee selected them, they were white instead of yellow.
Click the Easy Ease In button as instructed, and play the animation again. The difference is small but pleasant.
- The text turns to the dip in the pink line that it calls a discontinuity. Follow the instructions to hover over one of the two position keyframes at 00:25. Hold down an Alt key and watch the mouse pointer change color: it is now a Convert Vertex tool. Click the keyframe while the Alt key is still down, and the two keyframes at that time will merge. Release the Alt key.
The curve is still not smooth. Drag the remaining keyframe at this time to a vertical position that smoothes the curve. (I found that taking it to 500 was a good spot.) Note that the keyframe now has Bezier handles you can use to change the curve as needed.
- The text explains that you may want to work on the properties of multiple objects at once, for example, to coordinate events. Note the button to the right of each stopwatch button. The text calls this the Graph Editor Set button. (Shown on page 47.) Click this button for the title's Position, and for the snowflake's Position, Scale, Rotation, and Opacity properties. All five lines should appear in the Graph Editor. If they do not, follow the instruction to click the Eyeball button and turn on the check for Show Graph Editor Set.
- In this step you double-click the Position property of the snowflake. This wil put a white box around the entire Position curve. Drag the right edge of the box as instructed to make the snowflake come to its final position at the same time the title does. The curve will reconfigure automatically.
- Save incrementally, and show me the animation.
The text continues with a tutorial about drawing and smoothing a motion path.
Assignment 3: Create a short storyboard that presents a 10 second animated Logo. The logo can be one of your own design, or one "borrowed" from the Internet. This should take the form of a pitch for 10 second commercial message.
Assignment 3b: From your storyboard, create a simple animation as demonstrated in class of your animated logo. Use some of the techniques from this week's lesson to refine the animation.