1. A computer-implemented method for generating data for a support structure to be built with a digital manufacturing system, the method comprising: receiving, by a computing system, a digital representation of a three-dimensional model, the three-dimensional model having a virtual outer surface; projecting, by the computing system, a plurality of virtual rays toward the virtual outer surface of the three-dimensional model; determining, by the computing system, an intersection point formed between a projected virtual ray of the plurality of projected virtual rays and the virtual outer surface of the three-dimensional model; determining, by the computing system, a normal vector extending from the virtual outer surface of the three-dimensional model at the intersection point; determining, by the computing system, whether the intersection point satisfies a support structure requirement for the intersection point, wherein the support structure requirement for the intersection point is based on an angle formed between the projected virtual ray and the normal vector; generating, by the computing system, a support structure comprising a plurality of primary support members, wherein a first primary support member of the plurality of primary support members extends from the virtual outer surface of the three-dimensional model at the intersection point to support a first support region of the three-dimensional model when the intersection point satisfies the support structure requirement, wherein a second primary support member of the plurality of primary support members extends from the virtual outer surface of the three-dimensional model to support a second support region of the three-dimensional model, and wherein the support structure and the plurality of primary support members are different from the plurality of virtual rays projected toward the virtual outer surface of the three-dimensional model; graphically displaying, by the computing system, a composite digital model comprising the digital representation of the three-dimensional model and the support structure; receiving, by the computing system, a first user modification to the support structure, wherein the first user modification comprises a change to a location of one or more of the plurality of primary support members, a change to a size of one or more of the plurality of primary support members, a change to shape of one or more of the plurality of primary support members, a change to a total number of the plurality of primary support members, or any combination thereof; subsequent to the first user modification, bundling, by the computing system and based on proximity, the first primary support member and the second primary support member to form a unitary support member, wherein the unitary support member supports the first and second support regions of the three-dimensional model; and graphically displaying, by the computing system, the composite digital model including the first user modification to the support structure.