Parametric crease-pattern families
Eight families generate from parameters rather than from a fixed library: Miura-ori by rows, columns and zigzag angle; Yoshimura diamonds and the waterbomb tessellation by rows and columns; the square twist by its twist angle; Kresling by polygon order, storeys and angle; the pleated hypar by rings and sides; a box-pleating grid by divisions with optional diagonals; and seven classic bases - preliminary, waterbomb, blintz, kite, fish, bird and frog.
Every crease is an ordinary SVG line, so a placed pattern can be restyled, recoloured and rearranged like any other artwork, and the sheet outline is drawn heavier than the creases the way crease patterns are conventionally printed.
Two published crease notations
Creases can be drawn in the color convention crease-pattern designers read - mountain red, valley blue, sheet edge black - or in the Yoshizawa-Randlett notation printed origami books use, where the pattern is monochrome and a mountain fold is a chain line against a valley fold's dashes. A third setting applies both at once, so a pattern still distinguishes the two folds after a grayscale photocopy.
FOLD import and export
FOLD is the interchange format of the computational-origami community, and it is what ORIPA, Rabbit Ear and Origami Simulator read and write. Paste a .fold file and its vertices, edges and crease assignments render directly as editable shapes; a placed pattern can be saved back out as a .fold file for those tools.
When importing FOLD, 3D coordinates are read and their z dropped because a crease pattern is flat, an unrecognised assignment letter degrades to unassigned so a file written against a later spec still opens, and an edge pointing at a vertex that does not exist is reported rather than drawn.
Check Maekawa and Kawasaki conditions
Every generated or imported pattern is checked at each interior vertex against Maekawa's theorem, that mountains and valleys differ by exactly two, and Kawasaki's theorem, that alternating angles sum to 180 degrees. The readout names the first vertex that fails.
Those conditions are necessary but not sufficient, so the plugin reports that a pattern satisfies Maekawa and Kawasaki rather than claiming it folds flat. The plugin identifies patterns that do not fold flat: Kresling is a bistable buckling pattern and the pleated hypar cannot be folded with planar facets at all.
View flat-folded patterns
A pattern that folds flat can be drawn in its folded state as well as its unfolded one. There is no solver behind this: in a flat fold every crease turns through exactly 180 degrees, so each facet's folded position is a composition of reflections across the creases between it and a reference facet. That is exact arithmetic, and the fish, bird and frog bases fold into recognizable forms.
The folded view is unavailable for Kresling, pleated hypar, and unassigned box-pleating grids because these patterns do not define a flat-folded state.
The plugin does not calculate which folded facet lies above another. Facets are translucent, so areas with more overlapping paper appear darker.
Stays editable after placement
Placed patterns remember their settings. Select one and the plugin panel lets you change the family, its parameters or the notation and regenerate the pattern in place, with a single undo step restoring the previous version.