Inventories of a rock art site often do not include tracings due to time and budget constraints, however they are still important for aiding interpretation. While digital inventories from 3D models are expediting the documentation process, on-screen digitization is still tedious. We propose a method of automated tracing using open source spatial algorithms on enhanced 3D derivatives of an engraved rock art site. Automated tracing not only reduces time resources, but has also been suggested to improve interpretation by reducing subjectivity. We evaluate the results by comparing the automated tracing with on-screen digitization. While some subjectivity may be reduced with automatization, there is still subjectivity in the choice of parameters.