I've built an arrow that is controlled by two nulls - one at the start point and one at the end point. Using some trigonometry in some expressions, it works. When I move the nulls, the arrow resizes appropriately.
But when I try to parent one of the nulls to another object (like another null, or a shape layer), the null position jumps. And even after parenting, the parent null can't move the child null.. Any ideas?
Below are snippets of the controlling code, based on some scripts by others that I found online.
arrowlength controlled by
CellTower = thisComp.layer("startpoint").transform.position; Target = thisComp.layer("endpoint").transform.position; sizefactor = 100/(effect("ArrowSize")("Slider")); BeamLength = (length(CellTower, Target)*sizefactor)-150; [BeamLength]
rotation of the arrow controlled by
CellTower=thisComp.layer("startpoint").transform.position; Target=thisComp.layer("endpoint").transform.position; // Find the length of side a SideA = sub(CellTower, Target); // Find the length of side b SideB = sub(CellTower, Target); //Find the Angle between them -1*(270-(radiansToDegrees(Math.atan2(SideA, SideB))+180));