<p>Particle shape plays a pivotal, yet poorly understood role, in the response of granular materials. Previous studies have shown a clear dependence between their bulk response and the morphology of the constituent particles. However, due to the intrinsic variability of natural materials, the effect of shape cannot be fully isolated in physical experiments, limiting the studies to an overall comparison between the bulk responses of granular assemblies with different particle shapes. In this study, plastic ellipsoids with different aspect ratios and surface frictions are employed to study both their micro- and the macro-scale effect under controlled and repeatable conditions. Six specimens of more than 20-thousand monodispersed particles are subjected to triaxial compression, while <i>in operando</i> X-ray tomography is used to characterise the material response at multiple scales. For the first time, each individual particle is identified and followed throughout the test, which is in itself a major technical achievement, which allows the reliable measurement of the full evolution of inter-particle contacts. We show that the development of contact fabric anisotropy is driven by the geometry of the particles, independently from both local and global strains. Additionally, we observe that the role of inter-particle friction is strongly related to the degree of induced anisometry of the particles, affecting mostly the development of inherent anisotropy during the deposition process, which translates into higher macroscopic shear strength.</p>