Methods are provided for designing and generating a tool path for three-dimensional printing of a fiber composite part. The method includes defining a three-dimensional domain model and determining a set of boundary conditions for the three-dimensional domain model. The methods include applying a gradient-based algorithm to a predetermined stress state located within the three-dimensional domain model in order to: (1) optimize the three-dimensional domain model for minimum deflection or stress using a structural mechanics algorithm for a composite article, and (2) provide a topologically optimized fiber composite part design and fiber orientation field. The methods include using the topologically optimized fiber composite part design and fiber orientation field as an input to solve Gray-Scott reaction diffusion equations to generate an anisotropic tool path for three-dimensional printing of the fiber composite part.