During January 2025, Tenti refined the SAND ECAL endcap geometry within the DUNE/dunendggd repository, focusing on accurate simulation for detector studies. They implemented detailed C-shaped volumes and integrated both active and passive layers, ensuring the geometry closely matched physical specifications. Using C++ and Geant4, Tenti refactored endcap components and developed logic for precise module placement and material definition, supporting downstream analysis and calibration. The work demonstrated depth in detector geometry modeling and object-oriented programming, resulting in a more realistic representation of the ECAL endcaps. These enhancements improved simulation fidelity and addressed requirements outlined in issue #40 for the project.