The processing of 3D digital objects often requires the computation and analysis of their geometrical features. The normal vectors of the object’s surface in particular provide important information used in image processing applications. We present in this paper a new method for the estimation of normal vectors on the surface of a 3D digital object. It is both local and parameter-free. The proposed method involves the study of neighborhoods around points using planar sectors. Experimental evaluations using multigrid approaches show that it is both faster and more robust than state-of-the-art methods in the field, while being of comparable accuracy.