3 Replies Latest reply on Jun 3, 2008 10:02 AM by (shadowboxer)

    expression for rotating circle?

      I have created a circle (3D layer) that I have parented to a null object to drive it's Z rotation. I have the circle's X rotation set to -71 degrees. I want to create a turntable effect that has 3 pictures that rotate into view as the circle (null) rotates about every 5 seconds.

      My question is: Is there some script that allows you to parent the pics to the null (which will drive everything) so that they stay "on" the revolving circle as it rotates? In other words, imagine you place rectangles(pics) on a record player and at each 60 degree rotation the "pics" are rotated into full frontal view. If the circle was 10 inches in diameter, the pics would rotate on a circle/plane of say 8 inches in diameter.

      I've tried a couple of expressions but nothing that is correct and I've done some searching but can't find what I'm looking for just yet. So, I thought I would ask.

        • 1. Re: expression for rotating circle?
          David Wigforss-Hv1BNN Level 2
          Not sure if rotational values are represented with Orient to Camera, but try this.

          Make sure 3d is enabled for everything you create.. Create Null ("Null_Circle") in center of circle. Parent Circle to Null_Circle. Place object offset from the center. Create another null ("Null_Object") at the same position. Select Bull_Object and parent to Null_Circle, and change it's Layer/Transform/ Auto Orient_Camera. Precomp Object and parent to Null_Object.

          To change the objects based on a rotation you can use and if/else/else expression on Time Remap; place the contents on frames 1,2,3, and make sure your expression /24 (or whatever your framerate is).

          Another way I've swapped out pictures is if/else expressions on Opacity (ie 100; 0) parameters of layers.
          • 2. Re: expression for rotating circle?
            Level 1
            Try thins.

            Place the first picture where you want it to be on the turntable. Now add the other two pictures at exactly the same position so that all three are on top of each other.

            Now parent picture 1 to the turntable and rotate the turntable 60º. Then parent Picture 2 to the turntable and rotate another 60º. Now parent Picture 3 to the turntable. All three pictures are not children of the turntable and are distributed evenly around the turntable. Now parent the turntable to the null and use that to rotate the entire assembly.
            • 3. Re: expression for rotating circle?
              Level 1
              Yes, this worked. thank you.