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Sunday, March 4, 2007

Critique - Bouncing Ball (Sheba)

Direct Link: Sheba's Ball


I will need a side view (in Maya, in orthographic cameras, choose "side"), nothing in perspective. It's just easier to critique it that way.

Let's go ball by ball.

Big one (heavy): from frame 10 to 11, the ball goes up. Treat it from a pure physics point of view. A heavy ball would not go up for no reason. Have it just roll down the object. From frame 12 to 13 the ball goes suddenly down. It should continue its arc to the right. The ball should accelerate towards the end, so that the spacing gets bigger and bigger as the ball falls down. You have the ball travel a lot of distance from 12 to 13, but then less to 14, then even less to 15, it should be the opposite. As the ball lands, there is no bounce. Even a bowling ball would bounce a bit as it hits the ground.

2nd ball (medium): This one should come in higher. If you look at the height of the scene, it should fall from above the middle. That way it will interact with the object in the middle and the heavy ball. Right now it shoots into the scene from too low a point.
In terms of spacing, the medium ball hits the heavy one at frame 20. At that speed it would bounce off it immediately and the heavy ball would move a bit due to the hit. You have another contact frame at 21, which is too much. From frame 21 to 22 the distance is not far enough, it should travel more screen right. As it moves to the right it suddenly stops from frame 25 to 26. Then from 26 to 27 it moves screen left, which can't be, it would still continue the arc towards the right. This ball then suddenly stops as well. With a medium weight ball, it would bounce a few more times before it rests.

3rd ball (light): this one enters on frame 27 a bit too low, I would have it enter from a higher point, so that there is more opportunity for bounces. Spacing wise there are some issues. It enters at frame 27 almost like a pop. On frame 26 nothing is there, frame 27 it suddenly fully appears in the scene. That would suggest something very fast, but then you have the ball go down on frame 28 with a small travel distance towards the left. From 28 to 29 the ball travels screen right, which is impossible, even for a ball that's alive. From frame 30 to 31 the ball suddenly moves to the left. Is the ball further back than the others? Right now it looks like it's not hitting the ground like the other two balls. From frame 32 to 33 there is a sharp dip down. Track your ball with a dry erase pen and you will see that your arcs are not smooth and round, they will be too linear. From 33 to 34 the ball gets bigger. Is that because it's traveling towards the camera? Remember, I need the scene in a side view, so that we can concentrate on two axis only, no depth movement, nothing in Z. But even if you treat this scene as a 3D one, the ball couldn't just land and then change direction towards the camera.

Please change your camera to a sideview and think about the spacing of your balls, and especially your arcs. Study the bouncing ball examples on our site and track those balls with your pen. Study the curves of the balls as they bounce.

Please stop working on anything else and concentrate on that assignment. You need to master correct spacing and timing before you can move on. Right now there are too many mistakes in this assignment. Think in physics, pure gravity, that's it.

Alrighty? It's getting better, there was (almost) no craziness in this clip! :-)


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