#### CSC274b

Spring 1998

Ileana Streinu

#
Guest Talk

## Folding and Unfolding in Computational Geometry

### Joseph O'Rourke

#### When

Friday, April 3, 1998
#### Where

Pizza lunch provided; McConnell Hall, Room 403

This talk is a guest lecture in CSC 274 (Computational Geometry), but all are welcome and encouraged to attend. The
presentation will be comprehensible to all CS majors (guaranteed!). We only request that you indicate your likely
attendance to Ileana (streinu@cs.smith.edu) by Thursday 2 Apr so that we can order sufficiently many pizzas.

#### ABSTRACT

I will focus on three unsolved problems in computational geometry, all accessible to the inventive amateur, but all
frustrating the professionals. Two involve convex polyhedra: solid objects with flat faces and without dents. First, can
every one be sliced along edges and unfolded flat without overlap? No one knows. Second, given such an unfolding,
compute the 3D shape to which it folds. No one knows a general procedure for this. Third, can every chain of rigid links in
the plane (a "polygonal chain") be straightened without self-intersection? Here we have partial results (some obtained in
collaboration with Ileana Streinu and others), but the general problem continues to elude.

Last modified April 1, 1998.