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This is Magic with Math...
Most people think that expressions need programming experts... it's partly true, but you'd be surprised to know that one line expressions can easily create things that you would think to be much more complicated.
Talid Al Khatib finds the expression: Math.sin(time)*n to be such a magical one.. the "n" stands for number, and in the following project, we'll discover some of the potentials of this expression unveiled by Talid.
Let's Start by creating a 320x240 composition named "comp1". Import 2 blue solids (or any color but white) by the size of 100x100 make them circles by double clicking the elliptical mask tool. On the position property of the first apply the following expression:
[160,Math.sin(time)*80+120]
This expression means in English, that I want position[0] (the horizontal position) to be 160 through the composition, and I want position[1] (the vertical) to swing between two values, which are 80 over the center of the composition, and 80 under the center. Remember that the sine or cosine of any number is between negative 1 and 1. We add the 120 to make the movement start from the center of the composition, not from the top of it.
Now we want the other solid to move contrary to the first one. It means that when the first solid is 80 pixels over the center, the other one must be 80 under it. To do that multiply the vertical position with -80 instead of 80, and our expression will be:
[160,Math.sin(time)*-80+120]
Now we'll add a hand that connects the two circles. Import third solid and apply the following expression to the scale property:
[10,Math.sin(time)*250]
The third solid will act as an arm between the two circles
Now, all the "hard work" is done, you can do the rest while you are watching TV.
Create another composition named Comp2. Drag Comp1 to the time line of Comp2 and duplicate it three times, so you have four layers. Give them the following rotation values: -45, 0, 45, and 90. You'll have something like the following picture:
Now, create a third composition named Comp3. Drag Comp2 to the time line of Comp3 and duplicate Comp2. Enlarge the duplicated layer to 180x180 and make the opacity 30% (so it will look like a shadow for the other layer).
Add the following expression to the rotation property in the original layer:
Math.sin(time)*360
Add the following expression to the rotation property in the other layer:
Math.sin(time)*-360
The original layer will rotate clockwise, and the other will rotate counter clockwise.
You'll have something like the following picture:
Now we have the motion we want, and can still add some flavor to it. Import a new adjustment layer, let it be the top layer in the timeline. Apply the Hue/saturation effect from the "adjust" effects group. Check the colorize checkbox, rise the saturation to 100% and add the following expression to the colorize Hue property:
Math.sin(time)*360
You can do that by pressing alt then clicking the stopwatch left to the colorize Hue property. You'll see the colors of the compositions swinging between red and velvet.
That's why we shouldn't use a white solid. The white color won't respond the Hue/saturation effect.
Now let's import a new solid. Make it composition size, and make it the bottom layer in the timeline. Apply the grid effect from the render group, make the border value=1. Apply our expression to the corner property:
[Math.sin(time)*90+160,Math.sin(time)*90+120]
The size of the grid cells becomes a part of our motion like the following picture:
Notice that the final motion we have looks very sophisticated. But it depends only on a one line expression. So, it's not about how many lines I can write, it's about how can I make the most from the least I have.
Hope you enjoy it.
Tip of the day: If you want to make the world map look like a rotating globe, apply both offset and optics compensation from the "distort" effect group
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