Getting Started with Adobe After Effects - Part 6: Motion Blur

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Getting Started with Adobe After Effects

Getting Started with Adobe After Effects - Part 3: Keyframes and Effects

Apr 9 2013 12:00AM by jamesel   

In this lesson we will look at how we can use and edit keyframes to create motion and drive effects. In this example I have created a new composition (Shortcut control + N), and inside of it I have created a red solid (Shortcut control + Y). This solid has a few parameters. You can access them by expanding the little arrow icons.

new composition parameters

I’ll quickly go through each of these transform parameters as they are very important.

Anchor point is where the object will be rotated and scaled from. It defaults to the middle of the object so rotation and scale behave as expected, but it can be changed for interesting results.

Position is the layers position inside the composition. Note how it says 400,300. That’s X,Y coordinates. If the layer was 3D it would also have a Z coordinate. More on that later.

example composition

Scale and Rotation are as you’d expect, they scale and rotate the object from the anchor point. Scale is measured as a percentage and rotation as an angle.

Opacity is how visible the object is. At a value of 100% it is fully visible and at a value of 0% it is completely transparent. Go ahead and experiment with all of these values.

Note how simply changing a parameter does not create animation. However changing parameters over time does. As an example exercise, let’s click on the stopwatch for the position and move the object off screen. By clicking the stopwatch we have created a keyframe.

We can move our object off screen either dragging the X value until it reaches -400. We could also select the X value and type in -400, or we could select the object and hold down shift and press the left arrow key a number of times. Now the object is off screen and we have our one position keyframe, we can move forward in time by dragging the CTI over in our timeline. I have dragged mine to 2 seconds.

moving the object

Now at 2 seconds along in the timeline if we make a change to the position, After Effects will interpolate between the two positional keyframes and create movement. I’m going to set my positional keyframe at 2 seconds back to 400,300. This will bring the object back on screen. I can preview my work by pressing N at 2 seconds. This will end the work area. Now I can preview my work by pressing the 0 key on the numpad.

By default After Effects interpolates data linearly. For example: if on frame 0 we set a scale keyframe at 0% and at frame 10 we set a scale keyframe at 100%, we would know that at frame 3 the scale would be 30%. At frame 5 the scale would be 50% and so on. Let’s quickly erase our position keyframes by clicking on the stopwatch. This removes all keyframes. Now set your position to whatever the default is. The default size is half your compositions width and height. My composition is 800x600, therefore my red solids default position is 400,300. An easier way to do this is to right click on the solid and click Transform > Reset.

scale keyframe

Navigate to 0 seconds on the timeline and create a scale keyframe, set the value to 0%. Now navigate to frame 10 and set the scale to 100%. If you preview the animation, either by ram previewing or simply scrubbing your CTI along the timeline you will see the solid starts out invisible (0% scale) and quickly over the course of 10 frames fills the screen at 100% scale.


A visual way of displaying this information is by using the graph editor. Click on the scale parameter, and select the Graph Editor icon.

graph editor

The timeline changes into a graph. Along the X axis is time and along the Y axis is the scale value. Starting at 0% it quickly rises to 100% in a linear fashion. This is actually quite boring to our eyes. We can make the motion much more interesting by tweaking the curves. Note how our two keyframes in the timeline are now represented by the two red dots along the line. Click and drag to draw a box around them to select them. An easy way to create smoother animation is to right click one of the keyframes and select keyframe Assistant > then Easy Ease. The shortcut (whilst selecting keyframes) is F9.

Easy Ease

Have a look at the graph and see how instead of accelerating full speed, the scale gently ramps up to full speed, and then ramps down towards the end. This animation appears much less abrupt and is easier on the eyes. With the keyframes still selected, note how they have yellow Bezier curves coming off of them. You can manipulate these curves to create every type of acceleration/deceleration possible!

Bezier curve

As well as key framing our transformation parameters, we can also keyframe effect parameters over time to create animation. Each effect has its own unique parameters. Let’s go to our effects & presets window and type in fill. Searching for effects is a quick way to find an effect that you already know the name of. The effects are also sorted by categories if you don’t know the exact effect you need. I recommend experimenting with all of them to see what each one does. To apply our fill effect, click on the name and drag it onto the red solid in the timeline. The effect parameters appear under the effect controls, top left of screen in my case.

effect parameters

Nothing changes visually because the default fill colour is red, the same as my solid. What I’d like is to have the solid change from red to green as it scales up. To do this, navigate to frame 0 where we already have our first scale keyframe. Press the Colour parameter stopwatch under the effect controls. This creates a keyframe. Now navigate to frame 10 and click the red colour in the effect controls and change it to green.

colour effect

To show both keyframes on the timeline we can select our red solid and press U. This reveals all animated attributes on the layer.

animated attributes

We now get a visual representation of the change of colour over time. Remember that by default these keyframes are linear. We can also tell that by the fact that they are both diamond shapes. Compare them to our scale keyframes which look like hourglasses, the symbol for easing keyframes. Select both colour keyframes and press F9 or manually change the Bezier curves inside the graph editor. Now preview your work, the box starts off very small and red, and quickly eases to a large green shape.

In the next lesson we will look at how to create and animate text.

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