Final Project

Other than the Assignments, the main requirement for this course is the project. The project consists of at least two components:

  1. A paper describing what you did.

This should be a well-written document describing the problem you tackled (be it an artistic, implementation, mathematical, or writing challenge), what approaches you took, what difficulties you encountered, and what results you found, in addition to citing the relevant literature. Aim for a length on the order of ten pages, say, in the range of five to twenty pages.

     2. A presentation describing what you did (or how far you’ve gotten at the time of presentation).

You should prepare slides as PDF or PowerPoint, and you may also demo any software you wrote. All files should be submitted on the day of your presentation, or the previous day if there are complicated setups (in particular software). Pure blackboard presentations are discouraged except for the experienced. Presentations will take place during normal lecture time.

     3. If your project involves writing software, then you should submit the source code. If your project involves a physical object, you should show it during your presentation.

Projects can take many different forms. Here are the five main general categories:

  1. Build or design a physical structure that uses ideas from this course. 
    The structure might be furniture, architecture, sculpture, tool, or illustration. Your work should be both aesthetically compelling and technically grounded (though the latter need not be explicitly visible). The structure can be physical or virtual, though in the latter case the standards will be higher because of the reduced challenge. (One way to compensate is to make several virtual structures, e.g., connected in a theme.)
  2. Implement an algorithm, an illustration of a result, or a tool for experimenting with a problem. Typically, a good format for such an implementation is a web applet (written in JavaScript™, AJAX, Java™, or Jython) but other environments are fine too.
  3. Pose an open problem (or collection of related open problems). 
    You might pose open problems related to another field of research with which you are familiar, or pose something that comes to you out of the lectures. Ideally you should think about solving the problem, or how it relates to other problems.
  4. Survey a collection of two or three, or more related papers. 
    You should avoid overlap with the textbook, Geometric Folding Algorithms: Linkages, Origami, Polyhedra
    Often it is appropriate to combine with the next type of project:
  5. Write or substantially improve the Wikipedia articles for several geometric folding topics. Here, overlap with the textbook is OK. Be sure to follow Wikipedia guidelines.
  6. Try to solve an open problem. 
    This is the most ambitious kind of project, so the expectations in terms of results are correspondingly lower. What is important is to describe a clear problem, take (at least) one good approach to that problem, and describe to what extent it worked or did not work. You should not feel pressure in terms of grades to produce results, but you should spend substantial time thinking and trying to solve the problem. (In particular, if you succeed, you/we can write a research paper and try to publish it.) Collaboration is particularly encouraged for projects of this type, as is participation in the open problem session.

A number of sample project ideas, based on the topics covered in the course, are provided.

Deadlines

Project proposals must be approved by Class 14.

The paper is due by Class 24, the last regularly scheduled class session. The presentation is due somewhat earlier depending on when it gets scheduled; if your presentation is earlier, you are expected to have made less progress, but you should still give a clear description of the problem you are tackling and what you plan to do.

Collaboration

Collaboration is strongly encouraged, especially for research projects—this is often the key to successful research in theoretical computer science. You can work in a small group of students if you find common interests. You are also welcome to collaborate with anyone outside the course, including your research supervisor (if you have one) and the course staff. The only constraint is that your own contribution should be substantial enough, both in terms of solving problems and writing it up.

In any case, collaborators should be clearly marked in the project proposal, paper, and presentation.

Below is a list of possible project ideas. The source of the project idea—extracted from lecture (L) or class (C) notes, or old (O) lecture notes from Fall 2010—is noted when applicable.

Design/Build/Art

SES # PROJECT IDEAS
C06

  • Design and build a rigid origami structure.
C08

  • Design a fold-and-cut alphabet, preferably using a small number of simple folds.
  • Fold-and-cut art à la Peter Callesen.
  • Animate motion for 3D polyhedra flattening.
C09

  • How does real paper behave when folding a hypar?
L10

  • Create a Kempe-inspired linkage.
  • Design linkages to draw letters of the alphabet.
L12

  • Design and build a tensegrity sculpture.
C14

  • Design elegant hinged dissections.
  • Design / build reconfigurable furniture.

Coding

SES # PROJECT IDEAS

  • Higher dimension folding visualizer.
L03

  • Implement local foldability tester which generates a M/V pattern.
C04

  • Implement algorithm to generate an arbitrary black/white pixel pattern using checkerboard results.
C05

  • Improve/extend the interface or capabilities of Tess. Possibly 3D animation through interfacing with Rigid Origami Simulator.
C06

  • Port Tomohiro Tachi’s software to MacOS®/Linux®.
C08

  • Implement/improve on a fold-and-cut design tool, ideally including M/V state, degeneracy tool, and folded state. Possibly porting to Javascript™.
  • Animate motion for 3D polyhedra flattening.
L10

  • Create a Kempe simulation.
C10

  • Implement Kempe with splines.
L11

  • JavaScript rigidity/over-bracing /pebble algorithm visualization tool.
C11

  • Improve Henneberg construction/puzzle applet, port to web/JavaScript.
L12

  • Make a virtual tensegrity simulator.
  • Create a stress/lifting correspondence visualizer.
L13

  • Implement pointed pseudotriangulation algorithm.
  • Implement (infinitesimal) locked linkage tester/designer tool.
C14

  • Implement hinged dissection animator: slender adornments, general algorithm, and/or polyform algorithm.
C15

  • Implement continuous blooming algorithms.
L16

  • Implement orthogonal polyhedra unfolding.
L18

  • Combine gluing algorithm and Alexandrov algorithm to automate case studies similar to square or Latin cross.

Open Problems

SES # PROJECT IDEAS

  • Problem set 1, problem 2 many-layers version.
  • What is the minimum number of creases needed to be removed to make a crease pattern flat-foldable?
L02

  • Pseudopolynomial upper/lower bounds for strip method of folding anything.
  • Characterize possible seam placements.
C03

  • Characterize single-vertex flat-foldable 3D crease patterns.
L04

  • Optimal wrapping of other shapes by a square.
  • Optimal wrapping of a cube with an x × y rectangle of paper.
  • Do there exist other optimal wrappings of a cube by a square?
  • Lower bounds for checkerboard folding.
C04

  • Optimal 2×2 checkerboard folding.
C06

  • For sufficiently small, rigid motion, is local foldability enough?
  • Computational complexity of determining rigid foldability of crease patterns.
  • Can a paper shopping bag be unfolded from the flat state by adding extra creases?
C07

  • Universal folding of polyhedra other than boxes (e.g., polyoctahedra).
  • Is there a simpler proof of flat-foldability NP-hardness?
  • 3×n map folding. [Hard]
L08

  • Prove a lower bound on number of creases in fold-and-cut related to local feature size.
  • Higher dimensional fold-and-cut.
  • Instantaneous flattening of polyhedral complexes.
  • Connected configuration space of polyhedral piece of paper?
  • Prove conjectures about linear and circular corridor density.
C08

  • Fold-and-cut with arcs of constant curvature.
  • Can we continuously flatten nonconvex polyhedra?
  • Prove conjectures about linear and circular corridor density.
L09

  • Do triangulated creases for hypars exist for all numbers of pleats and angles?
  • Do circular pleats exist? [Hard]
  • What is the maximum volume whose surface is a folding of a teabag.
C09

  • What creases work for regular k-gon pleats?
  • Tight bounds for 1D pleat folding (allowing unfolding).
  • Find an explicit example of a 1D M/V pattern which requires Ω(n/lg n) folds.
  • Computational complexity of finding the shortest fold sequence to produce a given 1D M/V pattern (allowing unfolding).
L10

  • Characterize when there are folding motions for paper with holes.
  • Does adding a finite number of creases suffice to allow a folding motion between two folded states if the target folded state does not touch itself?
L11

  • Develop a faster 2D rigidity testing algorithm, or prove a lower bound. [Hard]
  • Characterize generic 3D rigidity. [Hard]
L13

  • Prove lower bound relating to feature size on number of steps to unfold polygon.
  • Improve step bound for energy method to unfold polygon.
  • Is there a unique minimum-energy configuration of a polygon?
  • Are there nonlinear locked trees of less than 8 bars?
  • Characterize locked linear trees.
  • Is there a locked equilateral anything in 3D?
L14

  • Are there nonslender adornments that never lock?
C14

  • 5D and higher dissections.
  • Efficient algorithm to check for matching Dehn invariants.
  • Any algorithm to find a dissection when one exists.
L15

  • Edge unfolding convex prismatoids.
  • General unfolding polyhedra. [Hard]
  • Can the star unfolding (or other edge/general unfoldings) be continuously bloomed?
  • Edge unfolding a convex polyhedron into o(F) parts?
C15

  • Does inverted sun unfolding (source/star) avoid overlap?
  • Does every Johnson solid have an edge zipper unfolding?
  • Does every convex polyhedron have a general zipper unfolding?
  • Which triangulated polyhedra are ununfoldable after attaching a witch’s hat to each face?
  • Are 12-face polyhedra unununfoldable?
  • Can prismatoids or even prismoids be fully band unfolded?
  • Continuous blooming of star unfolding, sun unfolding, all edge unfoldings, all unfoldings, or orthogonal polyhedra.
L16

  • Vertex unfolding convex polyhedra. [Hard]
  • Grid unfolding orthogonal polyhedra. [Hard]
C16

  • Convex-faced vertex-ununfoldable polyhedron.
  • Unfolding hexagonal polyhedra.
L17

  • Prove dependence of algorithms for Alexandrov’s Theorem on feature size.
C17

  • Algorithm for Burago-Zalgaller Theorem guaranteeing nonconvex polyhedron for any gluing.
L18

  • Complexity of whether a polygon of paper can be glued into a convex polyhedron.
L19

  • Which polyhedra have common unfoldings?
  • Are there two polycubes with no common grid unfolding?
  • Close the genus gap for nonorthogonal polyhedra with orthogonal faces.
  • Minimum perimeter (and area) folding of a sphere.
L20

  • Complexity of 3D min/max span.
  • Flat-state connectivity of open chain, orthogonal tree, etc.
  • Locked equilateral equiangular fixed-angle chain?
L21

  • PTAS or APX-hardness for optimal folding in HP model?
  • Unique foldings in nonsquare HP model?
  • Minimum number of cuts to unlock an n-bar open chain?
  • Smallest k-chain that interlocks with a 2-chain?
O21

  • Complexity of shortest flip sequence.
  • Maximum number of flipturns.
  • Characterize infinitely deflatable polygons.

Course Info

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Fall 2012
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