A finite element simulation approach, aimed at determining the equilibrium configuration of general fiber assemblies undergoing large displacements, and based on an implicit solver is used to predict the initial configuration of 3D interlock fabrics. Instead of simulating the weaving process, this approach offers to start from an arbitrary configuration where all tows lie in the same plane, interpenetrating each other, and to use frictional contact reactions generated by the model to gradually separate fibers from different tows, until achieving the stacking order between components defined by the selected weaving pattern. By this way, the initial configuration of the interlock woven fabric is characterized as an equilibrium configuration, and defined with only few parameters, without requiring any geometrical preprocessor. Once the initial configuration has been determined, various loading tests can be simulated in order to characterize the nonlinear behavior of the dry fabric.