How to parent rotation property to change position of another shape layer?

Question

Hi, I'm trying to make an animation with one shape layer that rotates, and another layer that moves with the rotation, but horizontally. Is there any way to parent the rotation property to the other shape layers horizontal position? To explain the attached photo: I want the lines under the round shape to move when I rotate the round shape, like a scroll effect horizontally.
Thanks!
/Jo

Rick Gerard · Accepted Answer

If you wanted Layer 1's rotation from -90 to +90 to correspond to a horizontal movement of 0 to 100 for Layer 2, you could use a position expression like this:

r = thisComp.layer("Layer 1").transform.rotation;
rMin= -90;
rMax = 90;
xMin = 0;
xMax = 100;
x = linear(r,rMin,rMax,xMin,xMax);
value + [x,0]

I would use the diameter of the wheel to calculate the circumference (C = π D) and use that to move the layer in x. This expression would do that and also compensate for any scale changes in the Wheel layer.

src=thisComp.layer("Wheel");
d = src.sourceRectAtTime().width;
r = src.rotation / 360;
s = src.scale[0] * .01;
c = d * s;
x = Math.PI * c * r;
value + [x, 0];

Mylenium · Answer

A simple linear() expression will do with this pattern: linear(refValue, refStart, refEnd, start, end) All that's required is to fill in the links to the properties and set the values. Mylenium

Sign up

To post, reply, or follow discussions, please sign in with your Adobe ID.

Sign in to Adobe Community

To post, reply, or follow discussions, please sign in with your Adobe ID.

Scanning file for viruses.

This file cannot be downloaded