Animation of a Point on Path

A point on path is animated by moving along its path. If the path is closed (for example, the interior of a circle, a polygon, an arc sector, or an arc segment) the animation proceeds around and around the path. If the path is a segment or an arc, the animation proceeds bidirectionally—back and forth along the path. If the path is infinite, as with a line or a ray, Sketchpad animates the point bidirectionally and tries to use the portion of the path that’s visible in the window. To specify the direction or speed explicitly or to make the point travel its path only once, create an Animation action button that animates the point.

To designate a specific portion of a line or ray as the domain for an animating point, construct a segment collinear with the line or ray and merge the point to the segment.