Image snapping for an image moves the cursor location to nearby features in the image, such as edges. In this paper, we propose geometric snapping for 3D triangular meshes, which is extended from image snapping. Similar to image snapping, geometric snapping also moves the cursor location naturally to a location which represents main geometric features in the 3D triangular meshes. Movement of cursor is based on the approximate curvatures which appear geometric features on the 3D triangular meshes. The proposed geometric snapping can be applied to extract main geometric features on 3D triangular meshes. Moreover, it can be applied to extract the geometric features of a tooth which are necessary for generating the occlusal surfaces in dental prostheses.