This WebGL app simulates how any origami crease pattern will fold. It may look a little different from what you typically think of as "origami" - rather than folding paper in a set of sequential steps, this simulation attempts to fold every crease simultaneously. It does this by iteratively solving for small displacements in the geometry of an initially flat sheet due to forces exerted by creases. It calculates the geometry of folded or partially folded origami using a dynamic, GPU-accelerated solver; the solver extends work from the papers Origami Folding: A Structural Engineering Approach and Freeform Variations of Origami. It also supports an immersive, interactive VR mode using WebVR. More information about the solver and the app can be found in the accompanying paper.

Live demo here, code on Github.

This app uses a compliant dynamic simulation method to solve for the geometry of an origami pattern at a given fold angle. The simulation sets up several types of constraints: distance constraints prevent the sheet from stretching or compressing, and angular constraints fold or flatten the sheet. Each of these constraints is weighted by a stiffness - the stiffer the constraint, the better it is enforced in the simulation.

Cauchy strain is a unitless measurement of how much a material is being stretched or compressed under load. The app can be put into a strain visualization mode that illustrates the strain across an origami sheet by mapping it to a color from blue (no strain) to red (max strain). Visualizing strain gives a sense of how much the distance constraints in the origami pattern are being violated (i.e. how much the sheet is being stretched). The strain at each vertex is evaluated by averaging the percent deviation of all its distance constraints with adjacent vertices. This deviation is reported as a percent of the total length of the distance constraint to remove scaling effects.