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The Bouncing Ball and other Sisyphilian exercises


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This will probably either die out or end up as a mini-blog.

Anyway ball bouncing in place[no decay]:


Ball bouncing across screen[with decay]


Critiques would be very welcome. 

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Check your arcs. The path the ball takes should be a perfect parabola. I traced the arc in green so you can see the non-parabolic path the ball is taking.

The speed of the ball will vary going up and down as it's pulled by gravity, but the speed of the ball going left to right should be consistent (there's ground/air friction so the horizontal velocity will slow down over time, but it takes a while). I traced the centers of the ball going down so you can see how the ball speeds up and slows down as it travels left to right.

You drew the ball spending 3 frames touching the ground. For a vanilla bouncing ball exercise animated on twos, it should only spend two frames touching the surface: one contact and one squash frame. Also the ball suddenly jumps too far to the right after the squash frame. To show that, I connected the dots from center mass of the ball on those frames

I'm not sure what software it is that you are using, but use the onion skin feature so you can see your arcs and the movement the ball takes from frame to frame. It'll be easier to catch problems with your arcs and timing that way.

It's not cheating to trace the path of your ball, putting a bunch of evenly-spaced grid lines so you can calculate the position of the ball in space every frame. It's not cheating to draw your arcs before drawing your character. Do whatever it takes to get your timing and spacing correct in your scene until it becomes more natural.

Put more time into your spheres. Draw them perfectly round/elliptical. Have your ground a different layer so it doesn't swim on the page. In the image I attached you can see that big thick black line; that's how much your floor moves during the scene.

If you are interested I can provide links to some resources to help you learn this stuff. If you are near Burbank, CA I could recommend some classes.


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