Important information can be obtained by simulating the deformation of composite reinforcements on a mesoscopic scale. The knowledge of the direction and density of the fibres in the deformed reinforcement affects the mechanical properties of the composite and the permeability of the textile reinforcement. The quality of the initial geometry of the finite element model is important for these mesoscopic analyses. The internal reinforcement geometries can be defined by some software. Nevertheless, these are based on certain simplifications that may have drawbacks. In this paper, finite element models are obtained from X-ray tomography. These finite element models are designed for all types of reinforcements and avoid problems of yarn interpenetration. A hyperelastic constitutive equation is used for the behaviour of the yarn made of fibre. The results obtained by the simulation for the compaction of a 3D reinforcement are compared with the experimental results with good consistency.