What Is Origami Simulator and What Can You Do With It?

Updated

Origami Simulator (origamisimulator.org) is a browser-based WebGL app that simulates how an origami crease pattern folds. Instead of walking you through sequential folding steps, it attempts to fold every crease at once by iteratively solving for small displacements in an initially flat sheet, driven by the forces the creases exert. You can use it to load example patterns, upload your own crease patterns in SVG or FOLD format, scrub through the fold, inspect strain, and export the folded result as FOLD, STL, or OBJ. It suits anyone who wants to preview or test a crease pattern rather than follow a step-by-step diagram.

How the simulation works

The core mechanism is simultaneous, force-based folding. The app starts from a flat sheet and repeatedly solves for small geometric displacements caused by crease forces, so the whole pattern converges toward a folded state rather than being animated crease by crease.

Performance comes from running the simulation methods in parallel in several GPU fragment shaders, written from scratch. The solver extends published work on structural-engineering approaches to origami folding and freeform variations of origami, and it uses ruling-aware triangulation to import curved crease patterns and pre-process them so the bending between creases is simulated realistically.

A practical way to picture it: give it a crease pattern with many folds and the app will try to move all of them toward their target angles at the same time, which is why the motion can look unlike a person folding paper in order.

What you can do with it

  • Control the fold amount. Slide the Fold Percent slider to set the degree of folding: 100% is fully folded, 0% is unfolded, and -100% is fully folded with the opposite mountain/valley assignments.
  • Inspect the model. Drag to rotate the model and scroll to zoom.
  • Load patterns. Open other patterns under the Examples menu.
  • Upload your own. Import crease patterns in SVG or FOLD format, following the app's linked instructions.
  • Export results. Save FOLD files or 3D models (STL or OBJ) of the folded state via File > Save Simulation as…
  • Visualize strain. Use Strain Visualization in the left menu of the Advanced Options to see the internal strain of the origami as it folds.
  • Try VR (with caveats). If your computer is connected to a VR headset and hand controllers, the app's instructions describe an interactive virtual reality mode; the site itself notes this may now be deprecated.

A quick workflow

  1. Open origamisimulator.org in a browser.
  2. Pick a pattern from the Examples menu, or upload your own SVG/FOLD crease pattern following the linked import instructions.
  3. Drag the Fold Percent slider between 0% and 100% (or down to -100%) to watch the pattern fold and to flip mountain/valley assignments.
  4. Rotate and zoom to inspect the geometry, and open Advanced Options to turn on Strain Visualization if you want to see where the sheet is under strain.
  5. When you have the folded state you want, use File > Save Simulation as… to export a FOLD file or an STL/OBJ 3D model.

Things to know before you start

  • It is not a step-by-step folding guide. The simulation folds every crease simultaneously, so the intermediate motion may not match how you would physically fold the model.
  • Curved creases get special handling. Curved crease patterns are imported and pre-processed with ruling-aware triangulation so the bending between creases looks realistic.
  • The project is open and extensible. The code is available on GitHub, and the original author invites interesting crease patterns for the Examples menu.
  • VR support may be stale. The site's own note says the VR mode may be deprecated, so treat it as experimental.

The site's page does not list pricing or login requirements, so check the app itself if those details matter for your use.