25 July 2010
When animating in Adobe Flash Professional, you can use the Motion Editor to control the shape of each property curve of a tween, except for the x, y, and z axes. By working with property curves directly, you can add complex curves to create specific tween effects.
Control points of property curves can be either smooth points or corner points. When a property curve passes through a corner point, it forms an angle. When a property curve passes through a smooth point, it forms a smooth curve.
Select a property keyframe and then press Alt-click (Windows) or Command-click (Mac) on the control point to toggle a control point between a corner point and a smooth point.
When a control point is in smooth-point mode, Bézier handles are exposed and the property curve passes through the point as a smooth curve. When a control point is a corner point, the property curve forms an angle when it passes through the control point. Bézier handles are not exposed for corner points.
In the screenshot below, the property curve in the Motion Editor shows a smooth point (Frame 8) and a corner point (Frame 17):
To set the point to a specific point mode, right-click (Windows) or Command-click (Mac) on the control point and choose Corner Point, Smooth Point, Smooth Right, or Smooth Left from the context menu that appears.