Keep in mind gravity's effect on an object - how it will cause the ball to slow down as it nears the top of the arc, and then speed up as it descends. Also, we don't want to just replicate reality, but exaggerate it. Really try and show that impact of the ball striking the ground.
What I will be thinking about when grading:
Clarity: Can we tell what's going on?
Animation:
Ease: Does it slow down as it nears the top of the arc and speed up before impact?
Squash and Stretch (if applicable): Does the ball appear to have a consistent mass, and does the squash and stretch happen at appropriate times? Stretches are more likely to happen at higher speeds and squashes would happen at impact.
Arcs: When the ball reaches the top of its bounce and comes back down it should move in an arc unless it's hitting something (like a ceiling). Can we see gravity's effect on the ball? Is the animation exaggerated to emphasize impact?
Technical: Does the ball move out of alignment at any point? Are there artifacts, or layers that disappear prematurely or last too long?
Don't forget to leave an artist statement on your blog, talking about your creative and technical process.
Supplementary Materials
Principles of Animation: Arcs
Principles of Animation: Squash and Stretch
Bouncing Ball Tutorial
Student Examples:
