Parabolic Bowl Motion Path Worksheet

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Parabolic Bowl Practice worksheet I

This worksheet explores the use of the motion path technique in flash animation. The motion path technique is very effective tool for describing complex motion of an object with out the use of actionscript (programming). With the path described on one layer and the object to be set in motion on the other, animators can cleanly separate content and behavior making complex animations from a collection simple paths. [More]

	How to Position Tween
	How Rotation tween
	How to Size tween
	How to Shape tween
	How to Color tween
	How to Alpha tween

Exercise I Simple Parabolic Bowl (sliding no friction)

Download this .fla file

Motion Path

Main Timeline

Instructions

Step I	In the first frame draw a ball and convert it to a graphic symbol named "ball_graphic". Then in frame 60 Right click and select "Insert Frame". Name the layer "ball".


Step II	Right click on the "ball" layer and select "Add Motion Guide".

Step III	Make the grid lines visible and set them to 25x25 pixels.

Step IV	In first frame of this motion guide draw a parabolic line with the Pen tool (using the grid lines) to describe the path for the ball. Center the parabola in the stage. (see how to use the pen tool)


Step V	In the "ball" layer, position your ball at the left end of the parabola (with the graphic symbol centered on the line) then create a new key frame in frame 10. In keyframe 10 center the "ball_graphic" to the middle of the parabolic guide path.


Step VI	In the "ball" layer right click anywhere between frame 1 and 10 and select "Create Motion Tween". Then set the motion tween to "Ease in" (-100%)


Step VII	In frame 20 create a new keyframe and position the "ball_graphic" at the right end of the parabola (with the graphic symbol centered on the line). Right click anywhere between frame 10 and 20 and select "Create Motion Tween". Then set the motion tween to "Ease out" (100%)


Step VIII	In frame 30 create a new keyframe and position the "ball_graphic" in the middle of the parabola (with the graphic symbol centered on the line). Right click anywhere between frame 20 and 30 and select "Create Motion Tween". Then set the motion tween to "Ease in" (-100%)


Step IX	In frame 40 create a new keyframe and position the "ball_graphic" at the left end of the parabola (with the graphic symbol centered on the line). Right click anywhere between frame 30 and 40 and select "Create Motion Tween". Then set the motion tween to "Ease out" (100%)


Step X	To create the bowl: create a new layer, name it "bowl" and copy and paste the parabolic line from the motion guide layer. Then use the free transform tool to resize the parabola so that the ball appears to slide on the surface of the parabola shaped bowl.


Note: The slight pause at the end of each animation cycle. This is because there is an extra fame in which the ball is stationary at the left side of the parabola. To fix this see How to use the gotoframe() function.