A comprehensive documentation of construction surveying is always desirable and, in the case of cultural heritage, imperative. Detailed layouts of heritage constructions help the understanding of the historical development of the building, however, drawing these plans is, usually, a manual process. In this paper, we present a new approach for obtaining accurate plans that include stone by stone drawings using 3D models. The proposed method overcomes the manual detection and drawing of features and individual stones. The approach works on 3D snakes (energy-minimizing active contour models) and on the detection of feature lines upon a surface curvature analysis. Our method can be applied to 3D meshes obtained with different techniques, but we have focused on 3D laser scanner techniques, which provide large amount of data quickly and accurately. Experimental results obtained on a romanesque church in Spain, are also given to illustrate the usefulness of the approach.