Armin Ilg improved vertex reconstruction geometry for the IDEA Detector in the key4hep/k4geo repository, addressing gaps in the geometry definitions that previously affected tracking precision and event reconstruction reliability. By refining the detector model using Geant4 and C++, Armin closed holes in the vertex region, which reduced systematic uncertainties and enhanced calibration. He applied the same geometry updates to the ALLEGRO Vertex, ensuring consistency across detectors. The work demonstrated careful geometry modeling and cross-repository collaboration, with a clean, traceable git history. Armin’s contributions focused on detector simulation, leveraging his expertise in C++ and Geant4 to deliver robust, maintainable improvements.