Draw parametric equations in AE, how to make them do deformation animation ?

[Taku Wilson]

Hello, I want to use the expression of ae to simulate the rose curve in mathematics. I applied a mathematical formula to the position attribute, and I can draw rose curves with different parameters.

However, I want to change the three-leaf curve into a four-leaf curve or another mathematical formula curve. I don’t know how to use expressions to make such an animation.

[Kevin Camp]

If you use the Write-on effect and apply this expression to the Brush Position property it will draw a rose curve with a set number of petals:

r = 5 ; // rate in seconds
n = 3 ; // number of petals
a = 300 ; // size
t = time * Math.PI + r ;
n2 = n / Math.abs( ( ( n % 2 ) - 2 ) ) ;
x = a * Math.sin( n2 * t ) * Math.cos( t ) ;
y = a * Math.sin( n2 * t ) * Math.sin( t ) ;
value + [ x, y ]

Adjust the r, n and a as needed.

In my testing it works pretty well, except for 6 petals, which for some reason only produces 3 petals…

[Kevin Camp]

I botched the rate… this should fix it:

r = 1 ; // rate to draw each petal in seconds
n = 4 ; // number of petals
a = 300 ; // size
n2 = n / Math.abs( ( ( n % 2 ) - 2 ) ) ;
t = time * 2 * Math.PI / n2 / 2 / r ;
x = a * Math.sin( n2 * t ) * Math.cos( t ) ;
y = a * Math.sin( n2 * t ) * Math.sin( t ) ;
value + [ x, y ]

[Taku Wilson]

I know write on, it can only make an object do a curve movement, I want to make a curve into another curve. thanks

[Taku Wilson]

I want to animate the transition of different curves by changing r n a slider

[Taku Wilson]

the four petals

[Taku Wilson]

I want to achieve this kind of change effect between different rose curves

[Filip Vandueren]

For most values of the rose curve you would need infinite amount of points before the curve lines up again. Do you want to limit it to a maximum number of rotations ?

like here: https://www.youtube.com/watch?v=PDrfcPgnhSA

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[Filip Vandueren]

Here’s my project that does it with a shape instead of write-on:

rose_curve_shape.aep 513 KB After Effects Project Files — Click to view

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[Taku Wilson]

Thanks, I found that the for loop is calculated every frame, which is very interesting!