The emission from Active galactic nuclei (AGN), originating from an accretion disc around a supermassive black hole (SMBH), can be used to probe hot and energetic astrophysical phenomena. X-ray radiation is the most powerful probe of the regions closest to the SMBH, with Doppler and gravitational broadening enabling SMBH spin determination. However, existing methods often rely on simplified models or overlook detailed radiative transfer effects. Additionally, the geometry, size, and location of the hot corona remain uncertain. This project aims to constrain the geometry of the hot corona in AGN and assess the reliability of black hole spin determinations based on these standard models. To achieve this, we aim to construct a single, self-consistent X-ray reflection model for AGN. This involves considering curved spacetime and the various physical processes at work (gravitational and Doppler broadening, ionization, polarization, fluorescence line emission, etc.) by implementing this into the SKIRT 3D radiative transfer code. Additionally, we aim to use realistic geometries derived from 3D magnetohydrodynamic simulations. Finally, we intend to compare the simulations to the observations, intending to measure the spins of AGN and study the impact of the corona geometry on these measurements. This project will be a significant step forward in the modelling and interpretation of AGN in the X-ray regime, crucial in the frame of upcoming missions such as XRISM and Athena.