GCCEC investigate ATLAS Coils geometry descriptions implementing in Cavern background FLUGG software applications and G4 Simulation packages. Both geometries have been exported from C++ codes into CATIA and positioned in common axes. Then both geometries were compared with so called “as built” 3D CATIA model developed by GCCEC recently and difference has been calculated. CATIA vs G4 analysis shows that simulation packages missing ~12t of dead materials for each coil. CATIA vs FLUGG analysis shows that Cavern background packages are over weighted on ~210t of dead material for each coil. Results were distributed to ATLAS simulation community (download report here …). From GCCEC – Archil SURMAVA, Besik KEKELIA and Nikoloz TSUTSKIRIDZE were involved.