When designing origami with box pleating, you may notice that as the grid dimensions increase, flaps and rivers in a finished model become thinner and thinner. Many times, this is unwanted, and can be resolved by simply using a larger paper or decreasing the grid complexity. However, as models require more and more flaps of different sizes and lengths, you might have no choice except to use larger grids. This is where level shifters come in to play, since they allow designers to widen flaps, create body parts, pleats, and so much more. In this section, we will only discuss one type of level shifter, but this one type of level shifter is extremely versatile and will pop up in most of your future designs.
To get a better understanding of the goal we're working towards this section, here's what a model enhanced with level shifters would look like:
The image above is just there to show the difference between a model with and without level shifters. Normally, designers will design the first model with level shifters included.
There are two steps to level shifters: packing in the actual level shifters, and then drawing in the flaps and rivers necessary to incorporate it with the rest of the model. In this section, we'll explore how to draw level shifters of different lengths and sizes.
First off, let's take a look at a simple example. This is a 4 unit tall and 4 unit wide level shifter with rounded corners. (The diagram shown below is a finished model, not a crease pattern.)
You'll notice that the center is slightly wider, specifically by two units, compared to the rest of the model. Now let's take a look at the crease pattern.
This all may look confusing, but let me break it down.
The first step to construct a level shifter like this is to determine the height and width (e.x. four units wide and two units tall). Next, subtract two from the width and draw in the appropriate level shifter. For now, just make all of the level shifters four units wide, as it will be the easiest. To draw a four unit wide level shifter, just subtract two from four and place the two diamond-shaped level shifters that amount of units apart. Like so:
Next, place another identical pair of the same level shifters below the first pair by four units. It may be helpful to draw an outline of the level shifter and then place in the level shifters.
Next, place in the crease lines. The crease lines will run in from left to right, like an accordion, alternating from mountain to valley. All of the diamond-shaped level shifters are mountain folds, as well as the lines connecting them. The creases directly above or directly below are valley folds. Try to copy the crease pattern shown above.
Let's take a look at another example.
In this example, you'll notice that there are actually two separate level shifters. However, the rules apply as usual. There are always two "opening" and "closing" pairs of diamonds, and they are both four units wide, with the top one being two units tall, and the bottom one being four units tall.
What if you wanted to make the level shifter even wider? It is possible, and it's fairly simple, however, will take up much more paper. Let's say I want a level shifter that is 6 units wide and four units tall. For that, the shape of the level shifter wil look like a heart instead of a diamond, but it will follow the same rules. Six units minus two equals four units, so first, I'll placce the two hearts four units apart:
Next, since it is four units tall, I'll move it down by two units, flipping the hearts upside-down. Once again, I'll draw down the frame of the level shifters to make it easier to visualize:
Next, the crease lines will follow a similar concept, where the outline of the level shifter is a mountain, however, only one portion of the heart will be a mountain fold.
I hope this article helped you understand the basics to level shifters. In the next article, we'll explore how to use level shifters in models with other flaps.