CPs - The Crane

It is time to talk about CPs in more depth. Again, I don't proclaim to be any sort of expert. This is simply a record of my thoughts, which, in a perfect world, will help some poor soul that is in a similar situation as myself. That is of course, a beginner CP folder searching the web for help. All of this assumes that I will actually improve over time as well. However, the light at the end of the tunnel is that I've read in many places that the only way to learn CPs is to fold them, fail, fold them again, and eventually you'll have folded so many that you begin to understand what's going on.

I'm going to start by studying the CP of the basic origami crane. Because I know how to fold this model, I've started to notice certain things about the CP because I know the order in which the folds take place.

The first thing I notice is the full length diagonal valley fold. This fold goes from the tip of the head to the end of the tail. While this fold crosses the entire square of paper, it is important to realize that the model is smaller than the diagonal length of the paper. In fact, the head and the tail are fairly close to each other. Regardless, this is the first fold to make in the CP as well as the diagrams.

When I say the first fold in the diagrams, I am refereing to the bird base. Go back and click on the bird base CP from Origami - The Basics and you will see a red valley fold from corner to corner.

The next folds to complete the crane are less obvious. If you recognize the bird base shape (a 4 pointed star with a cross connecting the inner section), then you would know to fold that base first. Note that there are always other creases that make the bird base collapsable, but these creases varry based on the model. Let's say that don't recognize the bird base. How do you have any idea which inner creases to fold first?

The trick is to look for main creases. What I mean by this is look for creases that form mirror lines. On the bird base CP, look at creases that divide the paper in half (the CP shows that they don't go all the way across the paper). If we imagine these folds as mirrors, then the points of the star are mirrored on either side. This suggests that the half folds are important creases.

Conversely, detail creases can be identified by looking for a fold line that bends across a mirror line. These detail creases occur later in the folding sequence than the main creases.

Let's start by considering just the bird base CP. We already have decided the first fold should be the main crease from corner to corner (red valley fold). This makes sense as it is the largest mirror line in the model. The points of the star (blue mountain folds) are formed by an angle bisecting fold of the main crease line. However, the inside points of the star are mirrored by the half folds on the sheet (blue mountain folds). These folds should therefore be completed at the same time. This also makes sense as we do not know the size of either fold without the other. The final creases are the short folds that run parallel to the main mirror line (red valley folds). This is the completed bird base.

This same logic can be applied to the origami crane model. We know to start with the corner to corner fold. If we look through the CP for other mirror lines, the 4 point star and the half folds are the only creases that don't bend over some other mirror line. If you can't see that the folds parallel to the main crease need to be folded next, think about what you need to do to make this model collapse flat. This brings us to the bird base.

If you are having trouble following me at this point, I suggest printing out the CP of the origami crane. Draw all of the folds on each side with blue or black lines for mountain folds and red lines for valley folds. This will help you see the progress we make with each fold as valleys will line up with other valleys and mountains with other mountains. This is because of the mirror lines I keep talking about. I have included a hand drawn CP of the crane, which will hopefully work for now.

In a way, the bird base is the finished CP of the origami crane. Many CP models are finished by folding the base and then completing a series of shaping folds to achieve the final product. In our case, the shaping folds have been included on the CP because they are simple.

To begin shaping, we must narrow down which folds we can make before others. An example of this is the head in the bottom right hand corner of the CP above. This section cannot be completed until all of the folds, or mirror lines, that pass through it are done first. We know this because the head is the last step in the diagrams. However, the zig-zag image of the head on the CP shows it mirrored across each crease. Simiarly, the almost rounded areas in the top left and bottom right are mirrored across some creases we have not completed yet.

Here is a picture of the CP with the creases we have folded already shown in black. From this picture, we can see the next steps in the model. You don't? Okay, look at all of the black lines and imagine them as mirrors. We know they're mirrors because that's why we folded them first. Do you see that each black line has colored lines on either side of it that match up? The next step is to fold anything that was lined up in the last step. Basically, we're narrowing the neck and tail of the crane as in the diagrams (you can fold these flaps of the bird base in either direction, you will get a crane with slightly longer wings one way and a crane with more interesting wings if you follow my CP exactly).

At this point, you can probably see the crane coming together. All that's left is to fold up the head and tail, fold down the wings, and inside reverse fold the head. Look up an inside reverse fold if you don't know what it is. I've included the CP with the remaining steps below.

I hope that you could follow this insane explanation of the origami crane. The crane is a simple model and I'm sure you can fold it, but the point is that you learned how the folds on a CP come together. Now I have to work on another model so that I can teach you.