Introduction

Motion paths are simultaneously the one of the best and worst things about animation in powerPoint. Best because they are so powerful in the effects that you can achieve and worst because it is so easy to get distracted into spending far too long trying (days) to work out how to achieve a particular effect.

One property of motion paths is the endless animation loop, such as the bouncing ball shown below

Instructions

Reasonably stepwise instructions on how create an endless loop animation.

Endless loops

  1. Insert a circle (<ALT>NSH, choose oval and then drag in the slide to create an oval. Hold down <SHIFT> to create a perfect circle) and add shading to make it look a bit more like a ball (<ALT>JDSF and select gradient).
  2. Select your "ball" and then click "ANIMATIONS" then "Add Animations" and then "More Motion Paths" and select "diamond" (<ALT>AAAPD).
  3. Open the Animation Pane (<ALT>AC) and double-click "Oval 1" in the Animation Pane to open the properties box for the animation.
  4. Under the "Effect" tab, drag the sliders for "smooth start" and "smooth end" to the far left. These are never useful for animation purposes but powerPoint insists on setting them by default.
  5. Under the "timing" tab set the duration to 3 seconds and set "Repeat" to "Until End of Slide. Click "OK"
  6. Edit the motion path by right-clicking anywhere on the (diamond shaped) motion path and choosing "Edit Points" (or left-click anywhere on the diamond and type <SHIFT><F10> and then Edit Points").
  7. In the "Edit Points" mode, the diamond will turn red and you can now see the "nodes" at each corner. Drag them around to create the motion path you desire.....
  8. In the demo below, the nodes were dragged to within half a ball width of the edge of the slide to dive the impression that the ball was bouncing off the edge of the slide

Hey-presto, instant and endlessly bouncing ball. Click on the demo to show two bouncing balls.

To create additional balls in the powerpoint (available here), simply duplicate the one that you have made and adjust the motion path. You can totally alter the motion path by entering "Edit Point" mode (red diamond) and right-clicking the path again.... the context menu that pops up this time includes an "Add Point" option. Add points. Lots of extra points were added (and then dragged around) to alter the path of the green ball. BTW, if you increase the length of a path, it is usually a good idea to slow it down by increasing the duration of the animation event.

Organic Anions

Of course, "Why", as in why would you ever want to do this, is a perfectly valid question and finding a use for endless loops is something that is entirely up to you. I generally use then to represent molecules, as in the animation below, where I am trying to explain how organic anions are secreted by renal epithelial cells. If nothing else, it is completely hypnotic and available for download here.

Gas Exchange

More fun with infinite loops here.

These animations are complex, but not necessarily difficult to achieve. They all use the same basic technique over and over again. The only tricky bit is making sure that the appropriate elements appear and disappear at the right moment. Take a look at the "Animation Pane" for these animations... they look a lot more complicted at first glance than they really are.