Concepts
A very traditional exercise in animation is to make a bouncing ball animation. A bouncing ball displays many of the major animation skills and concepts. These concepts include: arcs, timing, guides, key poses, in-betweens, timing, squash & stretch, and volume/scale.
In real life, a variety of forces impact movement and speed. To make animation feel "believable", those forces need to be taken into account. Ignoring how forces work often makes an animation feel "wrong".
Something dropped from a higher height will gradually pick up speed (due to gravity pulling down) and fall faster than a similar object dropped from a lower height (since gravity has less time to act on the other object).
Something thrown with more force will travel faster (and farther if not interrupted) than a similar object thrown with less force.
When the subject hits something else, the force of the impact often propels the subject away from the source of impact.
Movement often slows down over time, due to the pull of gravity overcoming the propelling force.
Just keep the laws of Physics (and what you have observed about how movement works) in mind while animating!
The mass and density of a subject have an impact on the movement.
If sense of the mass and overall shape changes too much, it can look jiggly or inconsistent - which is distracting.
Strategic changes in mass/position can make the subject look like it is getting closer or further away.
While all objects will fall at the same speed/rate regardless of mass, objects with very light density, such as a feather will be impacted more by air resistance and other forces such as the wind, so they may appear to fall more slowly.
Just keep the laws of Physics (and what you have observed about how movement works) in mind while animating!
Timing is closely related to frame rate. As the standard framerate of 24fps moves very quickly, we can create the illusion of smooth motion.
The closer the position, between different consecutive frames, the slower the movement. The further the position, between different consecutive frames, the faster the movement will look.
Change the interval of spacing to create a sense of accelleration and/or decelleration due to the forces acting on the subject.
The force of impact speeds up the movement, then as gravity begins to have an impact, the movement slows until gravity becomes stronger than the force of impact and speeds up the fall.
While you can draw all 24 frames per second, it is time consuming.
Now it is more common to use 12 frames where each frame is duplicated once. This allows animators to use only 12 images to create the full 24 frames and saves a lot of time, yet looks the same to our eyes.
When each frame displays 2 times consecutively, this is called having a "step" or "hold" of 2.
Animators often draw "guides" to plan out movement and timing.
A line, either straight or curved (depending on the movement), is drawn. Smaller marks are made along the line to plan out the interval or the spacing between positions.
The spacing of the intervals on a guide are placed due to the planned speed and and acting forces.
Unless an object is rigid like wood or metal, the principle of squash and stretch often applies. Forces acting upon objects often effect the exact shape. If you sit on a cushion, the cushion sinks down a little under the weight of your body. A softer cushion will sink more. A firmer cushion will sink less. Often this can be very subtle but slightly exaggerating the effect in an animation can add realism. Be careful though - too much squash & stretch can look a little too jiggly.
Since this is a bouncy ball, it will squash as the ball hits a surface and stretch as the ball bounces away from that surface.
- Key pose - the start or end of an action
- Breadkdown pose - a point of change in the action (there could be multiple)
- Inbetweens - anything between the key and breakdown poses
- Keyframes - states saved by a program to create automatic transitions in size, rotation, position, color or etc...
The Bouncing Ball Exercise in Procreate
Animating a bouncing ball is a classic animation exercise that provides opportunity for you to show all the concepts on the previous tab. While this exercise could be completed in a number of programs, we are using Procreate. Make sure your bouncing ball animation includes:
- An environment for the ball to bounce on
- A guide to plan out the movement (you'll submit a screenshot of the guide with the finished animation)
- Arcing movement
- Consideration of forces impacting the speed of the ball
- A consistent sense of mass and density
- Squash & Stretch
- Key poses
- A sense of lighting
While the demo video doesn't show every concept, it should give you just about all you need to complete the animation in Procreate. A couple other things to keep in mind:
- If you have multiple background layers, drag them on top of each other to create a group
- In the flipbook controls, tap on the first frame (your background) to set it as a background that displays across the whole animation
- Tap on the last frame (this should be your guide) and set it as the foreground so it will be visible across the whole animation
- "Add Frame" will always add to the right of the currently selected frame — so you can animate out of order with Key Poses if you choose
- Don't forget to toggle off the guide display when you export to video