PowerPoint Pendulums: Hidden Pivots and Harmonic Motion

One trick I seem to be using an awful lot in PowerPoint recently is a hidden pivot. Yesterday my colleague Scott shared a video (link) he had found of a set of pendulums carefully created to produce a really elegant and beautiful display when you set them all off together. Of course it didn’t take someone long to say “Now let’s do this in PowerPoint”, which I’m assuming/ hoping was tongue in cheek.

However for some bizarre reason I felt like the best way to unwind after working on projects all day in PowerPoint, was to make another animation in PowerPoint…

…and, this was the result:

Compared to the original:

Once I had looked at the video, and accompanying description that conveniently included the details of how they got the pendulums to work, it seemed fairly easy to create the effect in PowerPoint. But that was only because I used hidden pivots, rather than going crazy with motion paths. When I tried to explain that I didn’t think the animation was particularly complicated, no one seemed convinced, so here’s an explanation of how it works.

Most of the cool animations in PowerPoint are anchored on the centre of the object you are animating. For some animations it doesn’t really matter where the animation is anchored, but for others, in particular the spin animation, the centre point is crucial. Spin always turns the object about the centre point, which is great for creating something like a turn wheel or cog. But this is less useful if you want to have something swinging, like a pendulum for example. However there is a trick you can use to move the centre point of an object.

What you do is create a large shape centred where you want the new centre point to be, that covers the entire object you want to move the centre point for. Next you group your original object with the new shape, creating a new group with a centre point correctly positioned for spinning the original object.

After this you select the large shape you created and format it so that the fill and line colours are 100% transparent, and voila! You have something that looks like the original object you want to apply a swinging motion to, but with a centre point that lets you swing it with the spin animation.

One word of warning, this can create large areas of transparent objects all over you slides, which can make it difficult selecting anything below it, so you might need to rearrange the order of objects on the slide to make edits to something else. Using the selection pane can make this easier.

Finally once I had the 15 pendulums ready to swing it was just a case of calculating the timings they all needed in order to have the correct number of oscillations in the minute the animation runs for. Unfortunately, I think PowerPoint can’t quite do timings precisely enough to make the animation look perfect, but I guess that is what physics is for in the real world.

You can download my PowerPoint file here and take a look at the file if you wish.