Above is a project I have made that rotates the flags on the wire so that the tips of the flags always face down like they would due to gravity. You are free to use the project however you like. I like to put all the elements in a pre-comp and make a control layer at the top so that the elements you use to customize or keyframe the image are all in one space. My control layer has an option for rotating the wire with the flags in any direction, I wouldn't suggest rotating it more than 60 degrees either direction as the masks for the triangles start to detach from the wire at that angle. You can also change the color of the wire and the color of the outline on the flags by changing the wire color control and the Flag outline control. You can also change the repeating order of the color of flags by changing the colors on the control layer labeled Flag1, Flag2, Flag3 and Flag4.
To explain how it was created:
I have a wire that is a solid layer scaled down in the Y direction to a thin thickness so that I guarantee that my anchor point is in the center of the line . This is then pre-comped so that when I parent my flags to it the unlocked scale transform won't effect the flags. Each flag is a large triangle made with a mask on a solid that extends far past the wire line under the wire so that the wire sits on top of the flags. Every flags anchor point is set in the center of the triangle where the triangle crosses the wire. I then have an adjustment layer over the flags that has a linear sweep at 50% transition and a 180 angle so that it cuts flags from the front half of the screen down. Then in the wipe angle i wrote the expression, 180+thisComp.layer("wire").transform.rotation
so that as the wire layer rotates the wipe angle rotates with it cutting the flags off where they touch the wire. Then for each flag I parented them to the wire so they would move with it when it was rotated. After that, in each flag's rotation I put in the expression, -thisComp.layer("wire").transform.rotation
which would just turn whatever the rotation of the wire was to the negative value of that angle so that the flag always points down. Lastly I just pickwhipped all my elements I wanted to be editable to effects on a null that I named "Control Layer."
Please let me know if you run into any difficulties using this
Assistant Location Manager
Warner Brother Pictures