Getting pivot point of one asset in composite to pivot in respective to asset

I’m working on a project in touchdesigner that has multiple elements/images that are combined into a composite TOP. It’s a landscape and in the sky, I put a whale image that moves from one side of the screen to the other. This whale also has a fin that is a separate moviein TOP. I’m using a leap motion and want to control the rotation of the fin with that.

However when I rotate the fin, it doesn’t rotate from the point that I want. I want it to rotate from the top part of the fin and the point its pivoting from doesn’t even seem to be from a place in the image itself, but somewhere on the large background. I have tried messing with pivot points and I have not found one that makes the image pivot from a point inside the image. The fin is quite small in comparison to the background, so I’m not sure if that’s affecting the rotation as well.

Also if anyone could actually explain pivot points in detail, since the wiki is a bit vague. Thanks!

In TOPs the pivot point is the imaginary point in 2d space the image rotates&scales around. A pivot point of (0.5, 0.5) is the default, this means the center of the image.

See example attached. The pivot point is set in the Transform TOP to (1, 0.5). This mean the image rotates around a point at the utmost right of the banana image, but vertically at the center of the banana image. I composited a red dot which shows the pivot point around which the banana is rotated.
You can set this pivot point also outside the banana image. Experiment by setting the pivot point at (2, 0.5) and observe the result.

rotate_around_pivot.tox (894 Bytes)