3D weaving is an emerging textile technology that is now receiving great interest, particularly from the aerospace industry, for its potential utilisation in structural composites. The challenge and the driver for this work, is to generate numerical models to predict the mechanical behaviour of these composites. Presently, there seem to be no modelling software or framework able to generate such models with a sufficient level of detail, i.e. providing reliable predictions of mechanical properties and overall behaviour. The proposed modelling framework is based on a number of Python scripts that primarily perform three types of operations. They generate information such as yarn orientations, principal architecture and local fibre volume fractions, they locate and organise node pairs used for applying boundary conditions etc., and finally, they transfer information between different (other) software packages. The result of the final modelling stage is an FE model of the composite's representative volume element (RVE). It is created by using only a small number of input parameters, such as the size of the RVE, the number of yarns and their mutual interlacing, and the yarn crimp. The FE-model may then be utilised for various purposes, but is here used to calculate the homogenised elastic mechanical properties. The correlation between the model and the experiments is very good, both in terms of details in the architecture and mechanical properties. There are however some deviations that could be explained by the model being more regular than the real material.