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CP Guide
A Beginner's Guide to Crease Patterns
Constructs
Since a CP cannot explicitly describe a folding pattern for the model, the
creases must be filled in individually. This is a time consuming process,
but there are several ways of making it go faster. One obvious way is to
utilise the symmetry of the model - fold the model along the symmetry line,
and fold through two layers of paper. Efficient, but beware of paper creep,
particularly if the creases have difficult-to-locate landmarks.
A more accurate way would be to identify regions for which a standard
folding sequence exists, and then use that folding sequence to fill in the
creases.
Shaded areas
Shaded areas on CPs usually indicate unused parts of the paper. These regions
are get folded over, and get folded together with the rest of the CP. If
collapsing the CP becomes difficult because there's too many layers, you can
just cut out the shaded regions and fold from what's left.
Bird base construction
Bird bases are common sub-bases in CPs, particularly those with the diagonal
squares arrangement described previously (Figure 1). A folding sequence for
this bird base construct exist; it can be found in many diagrams (for example,
Ron Koh's T-Rex - Google for it!). This folding sequence is a quick way of
filling in the creases for a bird base section of the square. Obviously, this
method works only for bird bases appearing at the corners of a square.
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| Figure 1: Bird Base Subpattern |
Swivel fold construct
This construct is often found in patterns with angle bisection (90/45/22.5)
geometry. It's really a sink-type fold which allows you to form narrower
points for limbs and stuff.
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| Figure 2: Swivel fold construction. Red lines are valley
folds, blue lines are mountain folds. |
Grids
Models utilising box-pleating, either completely or in part, are easily
identified through the many 90 degree and 45 degree lines criss-crossing the
CP. In this case, doing the crease pattern first involves precreasing in a
complete grid over the starting sheet (even if some of the grid creases are
unused).
Hybrids which involve a mix of box-pleating and angle bisection folds often
contain interfaces across which the folding style changes (Figure 3). Here,
the vertical box pleats are "streamed" at an angle of 45 degrees to either side
of top centre triangular region.
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| Figure 3: Direction change construction. Blue lines indicate
mountain folds. |
Sinks
Sinks are typically used to narrow down flaps. They are fairly easy to spot -
look for regions of concentric crease polygons. As a simple example, fold a
waterbomb base and repeatedly open sink the central point, then look at the
crease pattern formed. Sinks are often found with the direction change
construct described above.