Planar cut and surface intersection software is an important part of a
ny computer aided design system. This paper presents two new ideas in
the numerical solution of such problems. The first is the notion of to
pology resolution. In this process, the structure of the intersection
curves, including the identification of closed interior loops, is dete
rmined prior to their actual numerical solution. The second idea is to
compute the intersection curves as the numerical solution of a differ
ential algebraic equation, yielding intersection curves which are (nea
rly) parametrized by arclength.