# Accessible Animation and Customizable Graphics
via Simplicial Configuration Modeling

Tom Ngo,
Jenny Dana,
Doug Cutrell,
Bruce Donald,
Lorie Loeb,
Shunhui Zhu

To appear in the Proceedings of SIGGRAPH 2000.

### Abstract

Our goal is to embed free-form constraints into a graphical
model. With such constraints a graphic can maintain its visual
integrity-and break rules tastefully-while being manipulated
by a casual user. A typical parameterized graphic does not meet
these needs because its configuration space contains nonsense
images in much higher proportion than desirable images, and
the casual user is apt to ruin the graphic on any attempt to
modify or animate it.

We therefore model the small subset of a given graphic's
configuration space that maps to desirable images. In our
solution, the basic building block is a simplicial complex-the
most practical data structure able to accommodate the variety of
topologies that can arise. The configuration-space model can be
built from a cross product of such complexes. We describe how
to define the mapping from this space to the image space. We
show how to invert that mapping, allowing the user to
manipulate the image without understanding the structure of the
configuration-space model. We also show how to extend the
mapping when the original parameterization contains hierarchy,
coordinate transformations, and other nonlinearities.

Our software implementation applies simplicial configuration
modeling to 2D vector graphics.

### Additional Information

- pdf
(240KB uncompressed).