CAP 151 -
Introduction to Computer Animation
Lesson 1 - Basic Animation (and Pre-Roll)
This lesson introduces the student to several aspects of the software used for the course. Objectives important to
- After Effects introduction
- Layout of the workspace
- Standard panels
- Basic terms
- Starting a project
- Keyframes and in-betweens
- Motion paths
We will actually begin with the Getting Started section of the text (before the numbered pages), move on to the Pre-Roll chapter, and continue through page 23 in the text for this lesson.
In the Getting Started section, the authors tell us that they used After Effects CS4, and that they used the Macintosh version to capture the images in the text. Consequently, you will see some differences between the screen shots in the book and what you will see in our Windows-based lab.
You will note that the disk that comes with the book does not include a trial version of After Effects. The authors refer us to Adobe's download page to get the current trial version of the product if we need to do so. Note that you have to sign up for a free Adobe ID in order to download from their site. This is a good idea, since the free account lets you use your ID and password to access Adobe TV, part of the Adobe web site that has video lessons on all of its current products.
In the usual textbook section about font conventions, we learn that the text will sometimes talk about "context clicking", which means right-clicking in a Windows environment. We also learn that After Effects "makes a distinction" between the enter key on the numeric keypad and the enter key on the QWERTY section of the keyboard. Great. In the text, they will say Enter when they mean the numeric enter key, and they will say Return when they mean the QWERTY enter key. In the olden days, there were no computers for ordinary people. There were only typewriters. Typewriters did not have numeric keypads, but they did have QWERTY keyboards, and electric typewriters had a Carriage Return key. This is why Enter keys are sometimes called Return keys. The one the text calls Return is the one that is in the same position as the Return key on an electric typewriter. For those of you who have never seen a non-electric typewriter, this video shows someone typing on a manual typewriter, with a carriage return lever.
The Pre-Roll chapter begins with some terminology and warnings:
- project - a container file for any number of components that will be used to produce output in After Effects
- comp, composition - a piece of a project that you create in After Effects; contains footage files or other comps
- footage - any resource used in a composition in After Effects; this includes video, audio, graphics, and other file types. This usage of the word footage is a reference to adding film footage to a movie.
- layer - once footage is added to a comp, that footage becomes a layer in the comp. This is like the layers that exist in a Flash project that we saw in CAP 101. Remember: a layer is just an object that you have added to your composition.
- application window - the window that holds all After Effects panels; the After Effects workspace
- toolbar - buttons for common tasks; an explanatory graphic of the toolbar buttons appears on page 3
- project panel - control panel for comps, footage, and folders to organize your project
- composition panel - like the stage in Flash, an area where you work with your footage . A warning appears in the text to remember that magnification and resolution (two settings on the comp panel) are different things. Magnification is your zoom level on your medium, and resolution controls how many pixels will be rendered in the output. Recommendation: keep them the same. Be aware that this panel has space to either side called the Pasteboard. This space does not appear in the final movie, it is used to hold layers that are not "on screen" yet.
- timeline panel - shows a timeline and keyframes for the layers in a comp, shows the length and order of layers; the text implies that this is the panel for creativity, as compared to the comp panel being the one for organization
- layer panel - a work area for individual layers (footage elements); contains a separate timeline that is relative to the layer itself
- other panels are discussed in various lessons
The text points out that when you add footage to a comp, a copy is not saved in the project file. What is saved is a pointer, which is a placeholder that knows the relative location of the footage file. This means that if you add footage that is not in the same folder as the project file, and you move the project file, the folder it is in, or the footage file itself, you will likely lose access to the footage. For this reason, you should keep copies of footage in the folder you use for each project, or maintain a file structure that does not change (which is impractical, if not impossible). Copies in your project folder will make that folder transportable from one workstation to another.
You can change your current workspace with the Workspace dropdown list. Each choice on the list gives you a different configuration of panels, each configuration related to particular tasks. You can go back to the default configuration by choosing Standard from the list.
You can also rearrange the panels on the screen, putting them where you want. This is not recommended while you are trying to follow the lessons in the text. If it is too late for that bit of information, note that the last choice on the Workspace list is Reset "Standard", which puts the panels back in standard locations.
The text introduces Adobe Bridge on page 12. We can return to this later. Our main objective is to learn After Effects.
This takes us to the first lesson (chapter) in the text, beginning on page 14. You begin a project on page 16, and will continue through page 22 in this lesson. (More next week.)
The text reviews some of the material above, and mentions that we can establish keyframes for most properties of a layer. A series of keyframes gives us timestamps to set a value. After Effects calculates the values to use in-between keyframes. This means that footage on a layer can be moved, rotated, faded in and out, and more.
Tutorial Notes and Questions
Note: Exercises should be carried out in the classroom. You will not get very much out of them by just reading, nor will you learn what is required by just experimenting on your own. Each exercise is meant to cover specific content that you will be required to know.
Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.
Before you start the any of the exercises, you should copy the required folders from the classroom server (or from your DVD) to your student data drive. This will enable you to complete each exercise, and avoid the problem of losing the footage files from one week to the next. You should only have to copy each folder to your data drive once. Doing it again will overwrite your copy and erase your work.
Tutorial 1 (Starting a Project):
- Start After Effects. You get a new project. Select the Standard workspace, and select Reset Standard.
Question 1: Why do you think the text asks you to select those two choices?
- Create a new folder as instructed. Remember to press the QWERTY Enter key when the book says to press Return. (Your keyboard may say Return. If so, good for you.)
- Step 3 tells you the shortcut for Deselect All (F2).
Question 2: It also tells you the "shortcut" to create a new folder. What is it?
- This step gives you a chance to save your file. Do so, and learn the shortcut for this as well as for incrementing a filename and saving.
Question 3: What is the shortcut to save with the current filename? What is the shortcut to increment and save?
- This step tells you to select a folder you have made, then create a new comp. Notice that it is reinforcing the idea of choosing a context (location) for something first, then creating something in that context. You are also told to set a Custom size for the comp, and a number of seconds to run. In passing, you are told not to change the Frame Rate of 29.97 frames per second. Follow the link I just gave you for an explanation of this weird number.
Question 4: What is the shortcut you are given for opening the comp settings screen?
- Examine the workspace as instructed and save your project.
- Step 7 tells you to select your Sources folder, and to use the first way to import footage: File, Import, File. Follow the instructions to open the indicated file.
- Step 8 introduces alpha channels. Graphic files typically have red, green, and blue channels, setting the color for each pixel. An alpha channel is a fourth channel that sets how opaque or transparent each pixel is as well. For the purposes of this exercise, you want to know that After Effects expects a file to have either a Straight or Premultiplied alpha channel.
Question 5: If you don't know which kind of alpha channel a file has, what are you supposed to do?
- Import the other files as instructed.
- Step 10 shows another way to import a source: double-click an empty area in the lower section of the Project panel. Follow the instructions and save your project.
- In this step you drag a TIFF file onto the Comp panel. Note the behavior described in the text: After Effects will try to dock the image file against an edge of the panel if you drop it near an edge. It will let you position it anywhere in the panel after you first drop it.
- The text tells us that the default background color for a comp is black. It wants to change this color. In a case like this, it would be good to have a tool that easily lets you test color combinations. I recommend the Visibone Color Lab, an online resource that lets you test combinations of colors for web pages. In this case, your manager (the authors) told you what color to use. Change it as indicated in the text.
- More new terms: transform, twirl up, and twirl down. The transform list is the list of properties you can change for a layer. (This list can vary, depending on what is in the layer.) The authors like to call opening the transform list "twirling it down". "Twirling it up" would be closing the list. (They must be unusual people.) A more useful term is scrubbing. The text tells you how to drag up and down to change the values (scrub them) in specific fields. The up and down motion causes the changes that can quickly lead to desired values. ("Show me paint fence...")
- Step 14 tells you to click the word Reset.
Question 6: Where is this word located on the screen?
You are told to move the layer in the comp panel.
Question 7: How do you constrain movement to one axis?
The text tells you to edit the Scale of the layer. (You are resizing it.) Use a similar technique to the one above to keep the aspect ratio. (The aspect ratio is the ratio of an object's width to its height. The aspect ratio of a standard television screen is 4:3, because when TV was invented, movies were made in that aspect ratio.)
Question 8: What must you do to rotate a layer in the comp panel? What do you do to change back to Select mode?
- Step 15 introduces keyframing,
key frames, and in-betweens - Computer animation is based on movie
animation. A movie is composed of a series of still photos, frames,
that are shown to the viewer rapidly.
In the image on the right, photos taken by Eadweard
Muybridge are shown rapidly, one after another. Each individual image is a frame. By developing a method
to display a series of such pictures in rapid succession, he was developing
a form of animation. (I am using a different method on this web page, but the effect is the same.)
In computer animation, we don't usually take photos, but we compose
frames. We create frames that show objects at different stages
of motion, like the frames of the buffalo. Each of them becomes a key
frame. We place each key frame on a timeline, indicating
the amount of time that should pass between successive frames. In-betweens
are frames that our animation software creates to fill in the gaps between the key
frames. (The buffalo has no in-betweens, just our imagination.)
It might be argued that we could have an infinite number of in-betweens
to create, since motion is often continuous, and each frame is a still.
As you can see by viewing this loop, an infinite number
of frames are not necessary to create the illusion of motion. The viewer's
mind participates in the illusion, creating many in-betweens to smooth
out the perceived motion.
The text tells you to twirl up the properties of the Nectar Plants layer. It tells you to type a letter to display just one property.
Question 9: What are the five letters listed as Transform shortcuts, and what property does each display?
Move the title layer as instructed in the text.
Toggle keyframing for the position property of the layer by clicking its stopwatch icon. This marks the position of the layer at the current time marker.
- Find the Current Time Indicator and drag it to the time indicated in the text. Note that the timeline is marked off at 10 frames and 20 frames after each second (10f and 20f). Move the title layer where the authors want it to be at this point in time. When you release the layer (drop it), a new keyframe is created. After Effects creates in-between frames that do not show on the timeline.
Question 10: What is the motion path that is displayed at this point?
Question 11: What are you told to do to see a quick version of this animation?
- In step 17, you are informed that you can drag the existing keyframes left or right to place them earlier or later on the timeline.
- Step 18 tells you to use the Keyframe Navigation Arrows to move from one keyframe to another. Note that the image in the text does not match your screen.
The image above was taken from my copy of After Effects, installed on my computer running Vista. The Keyframe Nav Arrows are on the left side of the panel, not the right side.
As the text explains, you can navigate to a keyframe and change its properties by manipulating the layer in the Comp panel or by changing the values shown for that keyframe.
Question 12: What method does the text describe for deleting a currently selected keyframe?
Carefully explore the instructions in this step for editing a keyframe.
- Add a background layer as instructed in the text.
- Change the Opacity property of the background layer as suggested in the text.
Question 13: Which hot key opens the Opacity transform?
- Use the two methods described to add the snowflake.mov file as a new Layer 2 to the composition. Note that the second method is the desired one in this case, adding to the composition about halfway through the timeline.
Question 14: Which method creates a new layer, and allows you to set where it starts on the timeline?
- Follow the instructions to view composition, and to change the start time for the snowflake layer.
After experimenting, use the keyboard
command (alt-home) to move the start of the snowflake layer to the start of the timeline. Save the project incrementally. We will continue next week.
In addition to the text, we will use several web resources for this course. This week's resources:
Assignment 1: Build a comp in After Effects as instructed in the steps above. Show me the animation as of the end of step 22.