Curved Crease Pattern Drawing Program

This is a rough sketch of a tool for drawing/editing a curved crease pattern with quadratic NURB curves (which can represent all conics). It is a collaboration between Erik Demaine, Amanda Ghassaei, and Jason Ku.

Installation

• Type npm install to do the necessary preparation (download svg.js and compile CoffeeScript → JavaScript)
• Open ccedit.html in a web browser such as Chrome

Usage

• To add a curve: Click "draw" mode, then click 3 points
• To manipulate a curve:
  • Click "drag" mode, and click on the curve if necessary (especially if "all controls" turned off, or if you want to delete)
  • Drag the 3 control points
  • Drag weight slider or enter a weight parameter (e.g. 1/sqrt(2)) on the left
  • Click "delete" button to delete the curve
• Use "save" button to export in (new) FOLD format
• Toggles:
  • "Grid snap" forces control points to lie on integer grid
  • "Extensions" shows part of conic extending the curves (dashed lines)
  • "All controls" shows the control points for all curves, making them draggable without selecting the curve
• Foci drawn for each curve
• No interface yet for dragging foci. We're still figuring out what the right interface is.