A computer-implemented method for inverse simulation of a plurality of fibers. The method comprises: providing a computational model for describing mechanical behavior of fibers; obtaining target geometry information describing a target configuration or dynamical behavior of the plurality of fibers; and inverse simulating the behavior of the plurality of fibers, using the computational model and the target geometry information, to calculate a target set of fiber mechanical parameters for the plurality of fibers. Fibers with the calculated target set of fiber mechanical parameters exhibit the target configuration or dynamical behavior. In some embodiments, the inverse simulation comprises using analysis-by-synthesis to help derive the target set of fiber mechanical parameters. In some embodiments, the inverse simulation uses a neural network to infer information about fiber mechanical parameters from the target geometry information. The invention also provides a method of training the neural network.