An algorithm for intersecting and trimming parametric meshes

We present an algorithm for intersecting finite-element meshes defined on parametric surface patches. The intersection curves are modeled precisely and both meshes are adjusted to the newly formed borders. The algorithm is part of an interactive shell modeling program, which has been used in the design of large offshore oil structures. We avoid unacceptable interaction delays by using a variant of the DCEL data structure that stores topological entities in spatial indexing trees instead of linked lists. These trees speed up the intersection computations required to determine points of the trimming curves, and also allows mesh reconstruction using only local queries.