Abstract: Systems and methods for generating data for a support structure to be built with a digital manufacturing system. Virtual rays are generated that extend toward a digital representation of a three-dimensional model. Intersection points of the virtual rays and the outer surface of the three-dimensional model are determined. Support structures extending from the outer surface of the three-dimensional model at the intersection point are generated. Support structure requirements can be used to determine if a support structure should be generated. A user can alter the support structures prior to the building of the three-dimensional model.