A procedure for tracing completely closed loops given implicitly by the intersection of two regular surfaces, without resorting to the parametric domain subdivisions or resulting in are overlapping, is presented. Our primary hypothesis is that the rotation index, a global geometrical property, may be a useful complementary tool to the local differential geometrical properties for improving the efficiency of the well-known marching-based surface-surface intersection algorithms. To validate this hypothesis, we devised a novel approach for incrementally computing the rotation index of a closed plane curve given implicitly while the curve is traced. Moreover, we also proposed its integration in a marching procedure that employs adaptative circular steps. (c) 2005 Elsevier B.V. All rights reserved.226491514