How to add this design tool to After Effects both as a guide and animation. The Golden Ratio / Spiral is a well known and useful tool when designing compositions. It frequently appears in nature which may explain why when we frame shots and images to line up with the spiral we find them asthetically pleasing.
You should not feel you always have to use the Golden Spiral - instead it's just another tool, like the Rule of Thirds. However, there is no simple way to get it to display in After Effects. And that's what this video is here to address.
I give the tutorial a C+ because of the workflow. All you have to do to eliminate the need for parenting layers to adjust the center of the spiral is to subtract the result from the current position value. If you also multiply the slider width by .01 of the comp width you'll get a little friendlier slider values to work with.
This is how I would modify the expression:
Radius = effect("Size")("Slider")/(thisComp.width * .01);
X = Math.sin(Math.PI*Radius)*Math.exp(Radius);
Y = Math.cos(Math.PI*Radius)*Math.exp(Radius);
Z = 0;
value - [X,Y,Z]
Using that expression eliminates the need to use parenting and layer space transformations. It also allows you to attach the expression to any property with X Y coordinates like Lens Flare Center or Particle World Emitter and just enter start values for X and Y.
I probably would have gone for a vector offset based on rotation instead of automating the position so you could wind and unwind the spiral path.