We develop a notion of categoric simulation of production flows. The flowis geometrically depicted as a certain subset in three modes (dimensions)—mass, space, and time. Each of the modes could be organized to a tree structure. We want to see the modes by means of an abstract mathematical notion—a category—which naturally captures the hierarchical/net structure of a mode even that it could be very complex. As a highly abstract notion, categoric simulation provides a broad perspective on simulation as something that can be developed and changed and thus has the ability to be a fundamental method of representing flows. We argue that this methodology has the potential of providing elegant, simple, and efficient solutions to problems arising in the manufacturing, as well as other applications concerning multivalued or varying flows in nets.