Systems and methods are provided for orienting a hair harvesting tool relative to a follicular unit to be harvested. Further, systems and methods of implanting follicular units are provided, which are based on the orientation of the existing follicular units or based on predetermined insertion angle. The provided systems and methods use image processing and image-generated topological skin models. In some embodiments surface fit is performed using, for example, a planar fit, quadric fit, cubic fit, mesh fit and parametric fit.
