  While many algorithms exist for tracing various contours for illustrating a
meshed object, few algorithms organize these contours into region-bounding
closed loops. Tracing closed-loop boundaries on a mesh can be problematic due
to switchbacks caused by subtle surface variation, and the organization of
these regions into a planar map can lead to many small region components due to
imprecision and noise. This paper adapts "snaxels," an energy minimizing active
contour method designed for robust mesh processing, and repurposes it to
generate visual, shadow and shading contours, and a simplified visual-surface
planar map, useful for stylized vector art illustration of the mesh. The snaxel
active contours can also track contours as the mesh animates, and
frame-to-frame correspondences between snaxels lead to a new method to convert
the moving contours on a 3-D animated mesh into 2-D SVG curve animations for
efficient embedding in Flash, PowerPoint and other dynamic vector art
platforms.
