CAP 151 -
Introduction to Computer Animation
Lesson 2 - Advanced Animation (part 2)
This lesson continues the last chapter, introducing more features of the After Effects interface. Objectives important to
- Separate Dimensions
- Motion Sketch
- Smoothing paths
- Auto-Orient and Motion Blur
- Value graphs and Speed graphs
- Roving Keyframes
- Hold Keyframes
We begin this lesson on page 48 in Lesson 2.
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: Separate Dimensions
- Load the project file you saved at the end of the last lesson. Close all comps as instructed, and open the comp for this tutorial.
- The authors introduce another variation on a command. Alt-shift-P will open the Position transform of a selected layer, and it will turn on the stopwatch (set a keyframe) at the same time. They ask you to do this for the only layer in the current comp, and also mention you could have opened that transform and clicked the stopwatch.
The keyboard command is quicker, but it is less likely that you will remember it, compared to second method. When you are learning a new product, learn the easy way to do something instead of the complicated way to do it, and you will be more likely to recall how to do it later.
- Move the time indicator as instructed. You should expect to see the motion path that appears.
- The authors tell you to turn on the Graph Editor Set button for the layer, then turn on the Graph Editor. If you don't remember how, look at the button illustrated on page 48.
- This step introduces the Separate Dimensions button, shown on the top of page 49. Follow the instructions to click this button, and the line in the Graph Editor changes into two lines, one for each axis in the composition. Note the instruction to change the graph type to Auto-Select if you do not see two sloping lines at this point.
- Move the time indicator as instructed.
Change only the Y position value, to place the ball on the floor of the scene. This should place a new keyframe on the timeline, and it should be selected. If it does not show as a solid yellow square, click it to select it.
Open the Edit menu and click Copy.
Move the time indicator to 1:15.
Open the Edit menu and click Paste.
- Run a Preview, but don't expect it to be perfect yet. The path will actually take the ball below the floor of the scene. That will be fixed in a moment.
Examine the illustration at the bottom of page 50. Follow the instructions in the text to "break" the connection between the left and right Bezier handles for the keyframes at 15 and 1:15. Drag those handles to make curves in the line like those in the illustration. (Watch the motion path in the Comp panel to see the effect of what you are doing.)
Preview the animation and tweak the Bezier handles as needed.
- The last step does not help as much as what I want you to do.
Close the Graph Editor.
Move the time indicator to the Home position.
Set a keyframe for Rotation for the ball.
Move the time indicator to the End position, and rotate the the ball clockwise about 100 degrees.
Save incrementally and show me the animation.
Tutorial: Float Like a Butterfly, part 1
- Open the file indicated for this tutorial.
- Select the butterfly layer and show its scale animation.
Question 1: What is the hot key to show scale for the selected layer?
- Change the Workspace as instructed.
- You should now have a Motion Sketch panel. This will let you draw motion with your mouse, while After Effects automatically saves keyframes for you.
- You are cautioned to practice drawing a motion path before actually drawing it, to get a timing for your motion that will fit in the desired timeline (5 seconds, in this case). Click the Start Capture button to begin capturing the motion path.
Question 2: What do you do after clicking the Start Capture button to actually begin the motion path?
Question 3: What actually ends the motion capture sequence?
RAM preview your path, and use Undo if necessary to begin the process again. Your path should not be identical to the one the author's chose. Try to make it better.
Save your project before continuing.
- No matter how well you drew your path, it will need to be smoothed. Access the Smoother Panel as instructed. It automates making the path smoother than your hand drawn motions made it. Use the Tolerance value to keep more or less of your detail for the path.
- As noted in the text, the butterfly does not rotate on the path yet. This step reviews two ways to fix this:
- Use Ctrl-Alt-O to open Auto-Orientation, or
- Click Layer, Transform, Auto-Orient
Open the Rotation transform as instructed, and adjust the butterfly to point into the direction of movement.
- Finally, use the Motion Blur feature as instructed. You may find that you like or dislike it. The comp supplied with the text actually has Motion Blur turned on already. Toggle it off and preview. Toggle it back on, and preview again.
Question 4: What is the procedure to change the the amount of blur in the effect?
Save the project at the end of page
55 as instructed.
Tutorial: Float Like a Butterfly, part 2
- Start After Effects. Load the project you saved at the end of page 55, Select the butterfly layer.
Change the Workspace to Standard. Go back into the Graph Editor. If necessary, follow the instructions to see the Speed Graph.
Note the features: this graph shows keyframes when speed changes in the animation. As before, we would like this one to be a smooth curve or series of curves not a series of stair steps.
- This step suggests trying to smooth out the curve by hand. It tells you to use the Easy Ease Out button on the first keyframe and Easy Ease In on the last keyframe. This is a good time to mention that Easy Ease In means make a smooth curve going into the keyframe it is applied to, and Easy Ease Out means to apply a smooth curve going out of the keyframe it is applied to.
As instructed, region select the rest of the keyframes, press Alt, and click any one of them to make them all smooth keyframes. Try adjusting them manually, reviewing your work with RAM Preview.
- In this step we learn the better method for smoothing the speed curve. Before you start, manually adjust the height of the first and last keyframes, or your result will be be a flat line.
Start by double-clicking the word Position.
Question 5: According to the text, what will that double-click accomplish?
Select Animation, Keyframe Interpolation. You should see a Roving dropdown; on it, select Rove Across Time.
RAM Preview to check the animation now.
The text informs us that this technique does not apply to the first and last keyframes. They keep their Bezier handles, which now affect the entire curve.
- This step shows another technique that may or may not apply to this animation. Double-click Position again. Select Animation, Keyframe Assistant.
Select Time-Reverse Keyframes to reverse the butterfly's course.
Save the project again.
Tutorial: Hold Keyframes
- It's not clear from the instructions in the text what the authors want to accomplish in this lesson, so play the QuickTime movie of the desired end result before beginning. (It is located in the Finished Movies folder for the project.)
Open the file indicated for this tutorial. The exercise will show us a new kind of keyframe, the Hold keyframe, and some new shortcuts as well.
- This step introduces a new time notation. Up to now, the text has used colons to separate seconds from frames. In this step, the authors switch to using semi-colons. Review page 60 to get the details on four timeline notations:
the semi-colon (Drop Frame), colon (Non-Drop Frame), and Frame notation, and Feet+Frames notation.
Drop Frame and Non-Drop Frame notations are both types of SMPTE (Society of Motion Picture and Television Engineers ) notation.
Non-Drop Frame notation numbers 30 frames per second, which gets out of synch with the actual rate after a significant number of frames. The text recommends using this system only if your production runs under a half hour. It typically uses colons as separators in its notation.
Drop Frame notation starts out the same, but does not use frame numbers 00 or 01 for any second that ends a minute, unless the minute number is divisible by 10. (Starts to sound like how you calculate leap years, for similar reasons.) Note that this does not mean frames are lost, it only means that we do not use some frame numbers in most minutes. Drop Frame notation uses semi-colons in its notation.
For this exercise, it is enough to know that the semi-colons in the notation used on page 58 tell us that this is Drop Frame notation. In this short animation, we will not be concerned with hours or minutes. A number like 2;20 will mean the timeline point 2 seconds and 20 frames into the production.
Navigate to the timeline point indicated (1;00). Select the indicated layer and show Position, Scale, and Rotation keyframes.
- A new shortcut is presented: to move 10 frames earlier on the timeline, press Shift-PageUp. To move 10 frames later in the timeline, press Shift-PageDown. Press Shift-PageUp, and change the parameters of the layer as indicated. Continue setting parameters at 0;10, 0;00, and the last frame in the layer.
- The animation moves the text on the screen, but the author wants it to be "harder-edged". Maybe this means "jerky"?
Select Position on the timeline to select all position keyframes. Since you want to select all the keyframes for Scale and Rotation as well, Shift-click those words as well.
Question 6: The text gives you a menu sequence to change the keyframe types. What is it?
This command changes the shape of the keyframes: diamond on the left side, square on the right side. This means "come in as linear, but hold before exiting". This change affected all the keyframes, but the authors did not want to change the ones at 1 second.
- Select all the keyframes at 1;00 using the marquee selection method. Ctrl-click one of the keyframes you selected, and all three should change to plain linear keyframes.
- Now we turn to another effect that will sometimes be useful: blinking. Caution: use this sparingly. In the early days of the World Wide Web, it became very popular for a while, but we all got sick of it very quickly. Like any effect, use it only where it is appropriate.
Move back to 1;00 as instructed. Select the frame layer (the red rectangle image in the comp).
Question 7: Another command is used to make the frame layer start at this moment on the timeline. What is it?
Turn on the Opacity feature of the frame layer. (Review the hot keys back on page 21.) You automatically get a linear keyframe set at 100% opacity. (100% means it is not transparent.)
Toggle the keyframe to a hold keyframe by Ctrl-Alt-clicking it.
Move 10 frames ahead, and set the opacity to 0% (transparent). Since you started with a hold
keyframe, that's what you get this time.
One more new technique: select both of the new hold keyframes. Press Ctrl-C to copy them. Move ahead another 10 frames, and paste. You will paste two new hold keyframes, 10 frames apart. Finish the tutorial as instructed and preview it.
Assignment 4: Revisit the logo assignment again. Apply some features from this lesson to make a new movie file for the customer to consider..