Advanced Video Editing


After Effects - 3

Bouncing Ball Exercise

 

Knowing how to animate is one thing, but you also need to understand the mechanics of motion. In fact, the standard animation test used by Disney for beginning artists was to draw and animate a bouncing ball.

This exercise will help you understand some of the important principles of animation, which you can apply when you want to add realistic motion to your motion graphics, which also includes the motion of text and logos. 


Courtesy AngryAnimator.com

Study this illustration above (courtesy AngryAnimator.com) and note how it shows the position of the ball in each frame (shown as numbers). Notice how the ball falls in an elliptical arc and the spacing of the ball in each frame. As the ball accelerates there is more spacing between frames. Also, as the ball bounces from the ground, it moves up very fast, so the spacing between frames is longer. As it nears the top of its arc, the ball slows down so the spacing between frames is much shorter. 

Furthermore, slowing down the action in a camera will reveal that the ball squashes and stretches. Tip: the ball doesn’t retain the squash and stretch for very long, - stretch on the frame just before it hits the ground; squash whilst the ball hits the ground, and stretch on the frame immediately after the ball bounces – very short. But you also want to make the squash and stretch very subtle. Too much squash will make the ball appear to grow larger than it really is, which  might look strange to viewers.

Before you begin animating the bouncing ball, you need to acquire the following assets. It’s very simple – just Google what you need:

 

Required Assets

Texture – if you want to create the illusion of a 3D ball, then look up textures for any ball that is round, such as volleyball, basketball, baseball, beach ball, etc. For example, if you Google "Beach Ball Texture" you’ll find under Images several 2D representations of beach ball patterns. Try to find one with a large enough resolution, ideally anything 800 x 600 or larger will work nicely.

Bouncing Ball Map with frame numbers – this is the timing sheet that you’ll use to assist your animation. You can simply drag and copy the one off this website into your project folder.


Here's an example of a beach ball texture.


Here's one of a soccer ball texture.


Prepping the stage

 

Step 1: Create a Project Folder

Name the folder so that you can easily find this project among your other projects.

 

Step 2: Create an Assets Folder

Inside the project folder, create an Assets folder. Store your required assets here.

 

Step 3: Open After Effects 

Don’t forget to save the project to your folder.

 

Step 4: Import your assets 

You can do this by simply double-clicking inside the Project Panel, which will open your Import window. Select the Assets folder inside your project folder and click OK. The entire folder will then appear in your Project Panel.

Note: You can also create New Folders in your Project Panel to store your Compositions (assuming you create several). Storing all your work in folders will help you avoid cluttering the Project Panel.



Step 5: Create a New Composition

Composition > New

Don’t forget to name your Composition – it's very important to name Compositions if you want to create different versions of your project. Go ahead and scale your New Composition to 1920 x 1080 (true HD resolution and usually the kind you’ll be using for any video that you shoot), set the frame rate at 29.97 fps and change the duration to 1 second and 10 frames.


Step 6: Create a New Solid

Go to Layer > New Solid. In the Solid Settings, name it Background. You're free to choose any background colour you like by clicking in the Colour box. Otherwise, leave it black. Then click on Make Comp Size to match the Composition size. Click OK.

 


Step 7: Drag the texture to the Timeline

Or you can drag the texture and drop it in the Composition window directly. 




Step 8: Create a Sphere

Go to the Effects & Presents panel and type in the search field, CC Sphere. Locate the effect and drag it to the texture clip in the Time Graph. The effect takes the 2D texture and wraps it around a 3D sphere.










Look at the Effects Controls tab in the Project Panel. 

You’ll notice the properties for controlling the rotation of the sphere and also its lighting. We’ll come back to this later. 








Step 9: Adjust the ball's scale

Select the texture clip’s Transformation properties – click on the disclosure triangle for the clip in the Timeline to reveal its properties. Adjust the scale so that the ball is smaller in the Composition. Another way to do this is to hit S for Scale and only the Scale transformation property will come up. Use the selection tool to move the ball to the upper corner of the Composition panel. 


Step 10: Add the Bouncing Ball map

Move the Ball Bounce timing sheet below the Ball clip in the Timeline. Then in the Composition window, Scale up the timing sheet so that the numbers hit the bottom of the frame. The timing sheet will be used only as a reference guide when you build the animation (it will not appear in your final animation).







The stage is set – time to animate!

 

Animating the Bouncing Ball

A good place to start animating is with the up and down motion of the ball (the Y axis). Beginning with the points where the ball hits the ground, you’ll notice this happens on frames 7, 17, 25 and 31.


Step 1: Move the Anchor Pivot Point

With the Ball in the Timeline selected, hit Y, which is the Pan Behind Anchor Tool, and move the pivot point from the centre to the bottom of the ball. If you just grab the pivot point without selecting the Pan Behind tool, you'll end up moving the entire image. The reason why you move the pivot point will become obvious when the ball hits the ground. 



Now move the ball to the bottom frame of the Composition window. The pivot point is the point of contact between the ball and the bottom of the frame (ground).


Step 2: Start Adding Keyframes for when the ball hits the ground.

Hit P for Position and move the playhead in the Time Graph to Frame 7. Then add a keyframe by clicking on the stopwatch icon next to the Position property. Then copy the keyframe by selecting it in the Time Graph (Command + C), move the playhead to Frame 17 and paste the keyframe (Command + V). Do the same for frames 25 and 31. You now have keyframes marking the position where the ball hits the ground according to the timing sheet.






Tip: to move the playhead to the specific frames, simply highlight the time counter in the Timeline and type in the frame number you want. Hit return and the playhead will be sent precisely to the frame you want.  


Step 3: Set keyframes for the top of the arcs:

You will now adjust for the points where the ball reaches its highest in each of the arcs. Remember, with the animation toggle stopwatch activated, After Effects will apply keyframes everywhere you reposition the ball. To start, go to Frame 0 (technically it would be Frame 1, but it’ll be easier just for this one keyframe to start with Frame 0), then raise the ball just to the top of the Composition panel so that it’s out of frame. When you release the ball in this position, AE will add a new keyframe. Move the playhead to Frame 12 – this is where the ball is at its second highest point. Repeat these steps for Frames 21 and 28. 



You now have the keyframes laid out for the most extreme points of the ball. The next steps will work on spacing the ball. This happens along the X-axis. 


Step 4: Open the Graph Editor:


Make sure the ball is selected in the Timeline and click on the Graph Editor (a button on the far upper right of the Timeline). 

You’ll use the Graph Editor to visualise the spacing of the ball more accurately and to get the arcs to look more consistent. 



Select the Position property for the ball to highlight the ball’s position on the graph. Note that the representation in up and down motion is reversed in the graph. That might seem a bit confusing at first.





At the bottom of the Time Graph, select among the buttons Separate Dimensions – this will split the Position property so that X and Y coordinates appear separately. You can then click on just the X Positions.



This is what the Time Graph looks like with just the X coordinates selected. 


Step 5: Delete the X keyframes between the first and last keyframe.

In the Time Graph, you can just lasso a marquee around the keyframes that you want to delete. Then hit Delete. The X coordinates in the Time Graph will now look like a smooth, ascending slope.



Step 6: 

Highlight both the X and Y Positions and toggle the Playhead to the first keyframe and then the ball to this position. Then toggle to the last keyframe and move the ball to its last position. You’ll notice the path of the ball in the Composition panel looks like it was essentially stretched out. The path is a rough approximation against the timing sheet of the motion of the ball.  




If you highlight just the X Position, you should see a straighter line ascending the Time Graph.



Step 7: Adjusting the arcs. (This step is tricky and requires some patience)

Click on the Y Position to highlight just the Y points in the Time Graph. Highlight the Y keyframe, which will then show you Bezier handles for each of the keyframes. Starting with the first keyframe, pull very gently on the Bezier to adjust the arc for the weight of the ball. Work your way down the arc for the other keyframes, adjusting the Bezier handles, again very gently. You can also use the Easy Ease buttons at the bottom of the Time Graph to reproduce more natural movement. 



With a little patience and very gentle movement of the bezier handles, you'll start to see the path of the ball look more like the path representing in the time sheet. 



Basically, you want to approximate the arcs as closely as you can with the arcs that are illustrated with the time sheet. You’ll have to apply a little give-and-take until you feel like the arcs are just right. Preview the ball’s motion and keep making adjustments as you see fit.

You can also choose the Tangent options, which are buttons at the bottom of the Time Graph. Using these can reset a selected keyframe or change the distribution of the arc. Try them to see what they do. Remember, you can always use Undo (Command + Z) and try again.

You can also pull the arcs up or down by simply dragging the keyframes up or down. 


Rotating the Ball

There are actually two rotations to speak of that you can apply. One is the rotation of the ball itself from its centre and the other applies a subtle tilt to the ball from the pivot point when it hits the ground and rises back up.

Applying tilt to the ball is a matter of going with the path that the ball takes.


Step 1: 

Select the ball clip and hit R to call up the Rotation property.

 

Step 2: 

Move the playhead to the beginning of the sequence. Click the Rotation stopwatch and make sure the Rotation is set to 0.


Step 3: 

Move the playhead to the frame just before the ball first hits the ground. Set the Rotation a few degrees to show it tilting back (try moving the Rotation about -18 or -20 degrees. A new keyframe gets added in the frame just before the ball hits the ground.

In the image below, you'll see the ball is tilted slight back just before it hits the ground.



Step 4: 

Move the playhead to the frame where the ball hits ground. Set the Rotation back to 0.  



Step 5: 

Move the playhead to the next frame (immediately after the ball hits the ground and bounces). Tilt the ball forward by adjusting the Rotation to about 18 to 20 degrees. 

In the image below, the ball appears to be tilting slightly forward as it leaves the ground.



Step 6: 

Move the playhead to the frame where the ball reaches the top of the first arc. Set the Rotation to 0.

 

Repeat the above steps until the path is complete.

 

To rotate the ball from the centre, you need to use the CC Sphere controls located in the Project Panel. Click to reveal the Rotation properties and you’ll find them for the X, Y and Z rotations. Choosing Y works to apply a little spin on the ball in the direction of the motion. See what the motion looks like using some trial and error, applying rotation to the X, Y and even Z coordinates.

 

Step 1: 

Move the playhead to the beginning of the sequence.

 

Step 2: 

In the Y rotation, click the stopwatch to add a keyframe.


Step 3: 

Move the playhead to the end of the sequence.

 

Step 4: 

In the Y rotation, turn the rotation dial clockwise a few degrees to add some spin to the ball.


Squash and Stretch

This technique will let you apply a little compaction to the ball when it hits the ground and some stretch when it falls and rises. What you need to do is use the Scale property to distort the ball.

 

Step 1: 

Select the ball clip and hit S for Scale. Now, make sure that you unlink the two numbers that you see (the proportion dimensions, which you can constrain or un-constrain), which will allow you to change the horizontal and vertical scale of the ball independently. To unlink, click the link button to the left of the numbers.


Step 2: 

You want to make sure that the ball is not distorted when it reaches the top of each arc. Move the playhead to the frame where the ball is at its peak and then click the stopwatch for Scale. Copy (Command + C) the keyframe and then move the playhead to the next peak where you can paste it (Command + V). Do this for the remaining peaks.


Step 3: 

To apply stretch when the ball falls, move the playhead to the second frame in the sequence just after the ball starts to fall. Then, adjust the scale to push in the ball and pull it out, making it look like it’s been stretched. You can make it slightly more pronounced just before the ball hits the ground. To make the stretch seem natural, don't exaggerate, otherwise you might make the motion look cartoonish.

The image below shows the ball appear to be slightly stretched on its descent.

 


Step 4: 

When the ball hits the ground, you want to adjust the scale to compress the ball and pull it out.

The image below shows the ball appear to be squashed slightly when it hits the ground.


Step 5: 

Duplicate the keyframes for the squash and stretch and apply them to the appropriate frames. Stretch the ball just as it leaves the ground and when it falls, squash the ball when it hits the ground. 


Add Motion Blur

Simply click the Motion Blur button to the right of the Ball clip. The button symbol looks like overlapping circles.

 


Finishing Touches - Lighting

Go back to the Effects tab for the Sphere effect and navigate to the Light and Shade controls. Below are some suggestions:


Under the Shade controls

  • Reduce the Ambient light to add more shadow and 3D illusion to the ball. 
  • Specular will apply a little highlight on the surface of the ball

Under the Light controls

  • Play with the light intensity, light height and direction as much as you desire until the effect looks satisfying. 


Finishing Touches - Background

You can turn off the Ball Timesheet by simply clicking on the eye icon to the left of the footage in the Time Line. 

If you want, you can even change the background colour, creating a gradient. 

Make sure you're no longer using Graph Editor so you can see the footage in the Time Graph. 

In Effects & Presets, select Generate and then 4-Colour Gradient. Drag it to the Background clip.


Exporting 

File > Export > Add to Render Queue

Under the Render Settings, leave it under "Best Settings" and make sure that you save the Output to your project folder. 

Click Render to start exporting.


Or you can custom the output by using Media Encoder

File > Export > Add to Adobe Media Encoder Queue

Then select the format you want to use. See Media Encoder instructions for more information.