Robust contour tracing.

We present a robust method for tracing a curve that is represented as the contour of a function in Euclidean space of any dimension. The method proceeds locally by following the intersections of the contour with facets of a triangulation of space. The algorithm is robust in the presence of high curvature of the contour, as well as being able to give reasonable results when the curve is self-intersecting. The algorithm accumulates essentially no round-off error, and has a well-defined integer test for detecting a loop.