Origami techniques

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Folding an origami christmas star
Folding an origami christmas star

This page shows basic information about the most commonly used techniques in the Japanese art of origami.

Contents

[edit] Origami symbols

  • Turn over.
  • Rotate.
  • Unfold.
  • Valley Fold.
  • Mountain fold.
  • Inflate.
  • Reverse Fold.
  • Sink Fold.
  • Repeat Behind.

[edit] Basic skills

Pureland origami is a style of origami that is done by creating only one fold at a time. Because of these restrictions, proponents of the theory have devised alternate methods of folding more complicated steps that have very similar results.

  • A valley fold is the first basic fold, in which you fold the paper forward onto itself.
  • A mountain fold is the second basic fold, in which the paper is folded behind itself. An easier way to do this is to turn the paper over first and then do a valley fold and turn the paper back over again.
  • A pleat fold is several evenly-spaced parallel mountain and valley folds. Also called an "accordion fold."
  • A radial pleat fold is an angled pleat fold, usually with a focus point on an edge or corner.
  • A blintz fold is made by folding the corners of a square into the center. This can be achieved with higher accuracy by folding and unfolding two reference creases through the center.

Valley fold

Mountain fold

Accordion or pleat fold

Blintz fold

[edit] Simple compound folds

  • An outside reverse fold consists of two radial valley folds extending from a single point on a central fold and a reversal of the center fold on the affected end, all done simultaneously.
  • An inside reverse fold consists of two radial mountain folds extending from a single point on a central fold, and a reversal of the central fold on the affected end, all done simultaneously.

Inside reverse fold

Outside reverse fold

[edit] Low-intermediate skills

  • A squash fold starts with a flap with at least two layers (for example, one flap of a waterbomb base). Make a radial fold from the closed point down the center of this flap. Open the flap and refold downward to make two adjacent flaps.
  • A rabbit ear fold starts with a reference crease down a diagonal. Fold two radial folds from opposite corners along the same side of the reference crease; the resulting flap should be folded downwards so that the previous edges are aligned.
  • A petal fold starts with two connected flaps, each of which has at least two layers. (For example, two flaps of a preliminary base). The two flaps are attached to each other along a reference crease. Make two radial folds from the open point, so that the open edges lie along the reference crease. Unfold these two radial folds. Make another fold across the top connecting the ends of the creases to create a triangle of creases. Unfold this fold as well. Fold one layer of the open point upward and flatten it using the existing creases. A petal fold is equivalent to two side-by-side rabbit ears, which are connected along the reference crease.
  • The simplest crimp fold consists of two reverse folds performed in succession so that the edges are still parallel. The crimp can be varied so that the edges are not parallel.

Squash fold applied to one flap of a waterbomb base

Rabbit ear fold

Petal fold on one half of a preliminary fold

[edit] Origami bases

In origami, there is a series of several bases that many models are created with.

  • The fish base consists of two radial folds against a diagonal reference crease on each of two opposite corners. The flaps that result on the other two corners are carefully folded downwards in the same direction. In other words, it consists of two side-by-side rabbit ears.
  • The waterbomb base consists of two perpendicular valley folds down the diagonals of the square and two perpendicular mountain folds down the center of the square. This crease pattern is then compressed to form the waterbomb base. The waterbomb base is an inside-out preliminary fold.
  • The preliminary fold consists of two valley folds down the center of the square and two mountain folds down the diagonals. This crease pattern is then folded together to form the preliminary fold.
  • The bird base, or crane base, consists of a preliminary fold with both the front and the back sides petal folded upward.
  • The frog base starts with a waterbomb base or preliminary fold. All four flaps are squash-folded (the result is the same in either case), and then the corners are petal folded upward.

Water bomb base before flattening

Preliminary fold

Fish base

[edit] Mid-intermediate skills

  • Swivel fold
  • Pentagon. Although most origami models start with a square or rectangular sheet of paper, a few start with a triangle, pentagon, hexagon, circle, or other convex sheet of paper. A pentagon can be traced (from a template) onto a square sheet of paper, or it can be folded from a square sheet of paper. One technique for folding a pentagon uses folds to calculate the golden ratio: (1+sqrt(5))/2. Another technique for folding a pentagon uses folds to divide a 180 degree angle into five (almost exactly) equal angles. The excess paper is often trimmed, before starting to fold the desired model. Pentagons are used in five-sided flowers, such as the cherry blossom and Marie's Rose.

[edit] High-intermediate skills

  • Most of the creases in a stretched bird base are present in the regular bird base. When forming this bird base, make sure to crease the triangle at the center corner through all layers. (If you unfold completely, you will see a small square at the center of the paper.) After forming the bird base, either partially unfold the paper, and/or "stretch" two opposite corners of the bird base. These two corners, their associated flaps, and the central square will all lie flat. The other two flaps will form a pyramid. Rabbit ear each flap that is in the pyramid, so that the model lies flat. All of the raw edges will lie along the centerline of the model. The stretched bird base is used in Lang's Bald Eagle, Greenberg's Eeyore, and some other high-intermediate and complex models.
  • The open sink usually involves opening out the paper, and reversing creases to make a waterbomb base in the middle of the model.
  • The open double sink is equivalent to making an open sink, and then open-sinking the point in the opposite direction. When made in a single step (after pre-creasing), it can be easier to make than a single open sink, because it does not require neatly reversing the point. The open double sink is used in many box-pleated models.
  • The closed sink simultaneously makes a locking flap inside of a sink. It is difficult because the paper cannot be opened out further than a triangle. This technique is illustrated in the Origami Forum's thread #462. The closed sink appears in some high-intermediate and complex models.
  • The twist fold is a variation on the stretched bird base. The three-dimensional intermediate shape can be either a box or a pyramid. Instead of the pyramid being two separate flaps, the pyramid is a continuous piece of paper (similar to a "pouffed" up handkerchief). Instead of rabbit-earring the point down in one direction, each side is "twisted" clockwise (or counter-clockwise) around the pyramid. And instead of having just two sides to rabbit-ear, there can be any number of sides to twist around the pyramid. The twist fold is used in many of Fuse's modular boxes, Marie's Rose, and some other high intermediate and complex models.
  • The spread squash is a variation on the squash fold. It is used to flatten a closed flap or twist fold. Instead of creating a long point to one side of the flap's base, the spread squash creates a wide splat around the flap's base. The spread squash is used in the eyes of Engel's Octopus, in Marie's Rose, and in some other intermediate and complex models.

[edit] Complex skills

  • The closed unsink everts a closed sink without completely opening out the affected paper. In theory, it is "just" the opposite of a closed sink. In practice, it is very difficult, because the paper being "popped" into place usually must be pulled (not pushed), and because it involves simultaneously folding over a locking flap that is hidden inside the sink. The closed unsink appears in some complex models, such as a few of Lang's insects.

[edit] External links

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[edit] Further reading

Almost every origami book has basic instructions and a set of folding symbols. These are books that happen to have detailed explanations of these techniques, and how the techniques are related to each other.

  • Robert J. Lang. The Complete Book of Origami: Step-by-Step Instructions in Over 1000 Diagrams. Dover Publications, Mineola, NY. Copyright 1988 by Robert J. Lang. ISBN 0-486-25837-8 (pbk.)
Pages 1-30 are an excellent introduction to most of these skills. Each of these 13 models is designed to let you practice one skill several times. Unfortunately, the remaining 24 models leave out lots of pre-creases.
Pages 1-88 explain how the crease patterns of the classic bases are related to each other, how they are examples of fractal design, and how it is possible to generate arbitrarily complex origami designs.
  • Robert J. Lang. Origami Design Secrets: Mathematical Methods for an Ancient Art. A K Peters, Natick, MA. Copyright 2003 by A K Peters. ISBN 1-56881-194-2 (pbk)
This book shows how crease patterns and folding techniques are related to the large-scale structure of a model. It also shows how closed-unsinking was derived, using Lang's TreeMaker software for prototyping arbitrarily complex origami designs.
This is an excellent book about modular origami, and serves as a great introduction to geometric models and designs.
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