The simulation is being used to produce artificial events for physics analyses. In the ATLAS experiment at LHC CERN, Geneva, Switzerland, a simulation is carried out on the GEANT4 platform. The GEANT4 uses geometry descriptions as an input for the modelling of the propagation of the particles in the material. Adding CATIA (Computer-Aided Three-dimensional Interactive Application) CAD application into simulation infrastructure brings an opportunity for the early study of the detector geometry for precise simulation. The paper describes a method of calculation of X_0/λ radiation parameters for the CATIA native geometry descriptions. The core part is the so-called scanner function, enabling the generation of the control points on the geometry, where the calculations will carry out. The algorithm contains as well, the initial transformations of geometries before scanning and output interfaces with the standard applications Root and Excel.