Engineering the perfect pop-up book

Growing up you may have had a shelf with a few simple pop-up books, pull the tab and the cows head moves from side to side. Today’s pop-ups are feats of engineering. Science Friday talks to pop-up artist Matthew Reinhart about the mechanisms and structures that drive his designs.


Growing up, you may have had a shelf with a few simple pop-up books.

Pull the tab and the cow's head moves from side to side.

Today's pop-ups are feats of engineering.

'Science Friday' talks to pop-up artist Matthew Reinhart about the mechanisms and structures that drive his designs.

There is something kind of, like, amazing about taking something that's just paper, just like this 2D thing, and sort of rearranging it and cutting it up and making it into something that you can't believe happens.

My name is Matthew Reinhart, and I am a pop-up book artist.

The background that I have in zoology and anatomy and all those sort of things, that comes in a lot to the way that I engineer because you look at the way things come together, the way things move.

If the body goes outward like this, you don't want the folds to be going inwards on something.

All these things work together so that it feels natural.

The other one that I think made the biggest impact on me were Transformers.

Just the actual toys, there was something about the way that they went together and became something else, those transformations, changing.

That aspect, I think, really stayed with me, and I think that that's why I still collect Transformers and have thousands.

I'll write out an outline, just a basic idea of what the pop will be... That's it.

I don't know how it's gonna happen with all the engineering.

I just know that that's what I want to happen.

The next step is actually engineering, by hand.

Like, there isn't a computer program that does this stuff.

It's like low-tech engineering.

We're using really simple stuff.

Me cutting up paper and folding it and taping it.

I use, like, an artists tape.

That makes a nice hinge.

There's another way that you can attach paper, you know, so that one piece will go through kind of another.

It's a really loose hinge.

There are really two main mechanisms.

V-fold is probably the most important.

It causes things to move in an arc.

Some of my pop-ups may use 20 of them all working in different directions to make one thing happen.

The second one is something called a layer.

Basically, a box that's flat, and then opening up.

So that usually is used for structure.

You have to first do the base structure and how that's gonna fit on the page.

You get the core built, and then the arms can work around it.

The V-folds that are moving directly off of the base page -- those are the first ones that are really gonna activate.

Opening the page is a chain reaction sort of event.

That's where the energy is coming from to make these pieces work.

That energy is distributing out to the first mechanisms that are built off of it.

As you continue to open, there continues to be power, and that is moving further outward.

You can build a V-fold, and you can build a V-fold off a V-fold.

I mean, it can go on indefinitely, and the further I work away from the base page, it's going to happen later.

Sometimes people only open it, you know, maybe 90 degrees, just to get a peek in there.

You want something to happen in that first bit that will get them excited.

And there are certain ways that you can adjust things so that something happens within that short amount of time.

Narrow V-folds, they open completely very quickly because there's not a huge arc that they have to move across.

But they also don't move very much.

There's also very wide V-folds that move like this huge arc.

So you may not see any of that action until those last moments before you open the book completely flat.

But usually, if you're working close enough to the center fold, then you're getting all that happening relatively soon.

There's sort of rules with some of this engineering, and I'll bend the rules to make those mechanisms work.

I've used different types of paper and things.

There's one pop-up from my dragons book that actually uses tissue paper garlands to build its body.

Usually, when you make a pyramid on a pop-up, structurally, it just sits there.

I didn't like the size that I could get from doing that, so the pyramid actually flips.

Later, I started making pops that there was some way of affecting that 3-Dimensional object to turn into something else.

It's like, I, you know, I cheat and get an extra pop in.

In LEGO, there's like -- I think it's the tallest one I've ever done.

It almost pokes you in the face.

You know, everyone who's seen it is, like, kind of freaked out that that thing can get, you know, like, this high within the book.

Most of what I do, I don't know how I did it.

I mean, I do, but I don't.

It's like, 'What were you thinking about on that one?'

You have to rebuild things over and over and over again, make sure they work right.

One little thing could go wrong, and you have to figure out things to counter that.

I built the Optimus Prime from my Transformer pop-up probably about 25 times because there's so many different moving pieces that have to work.

Making pop-ups is something a kid can do, you know?

You've got the material and you've got the tools, like scissors, and you've got some tape.

I do it for them.

I do it for, of course, myself.

I want to wow me.

I want to wow any reader, you know, at any age.

Hopefully it gets them excited about, like -- 'How's this done?'

'Can I do this?'

'I want to make this' and 'I want to be creative.'