Developed and integrated mass properties calculation functionality into the FreeCAD/FreeCAD repository, enabling engineers to compute and display key physical properties such as volume, mass, density, surface area, center of gravity, and inertia directly within the Measure workbench. Leveraged C++ and Python to create new inertia data structures, implement unit conversion, and build a Python-based UI for seamless user interaction. Addressed a regression in the Part Workbench by refining sub-element handling and selection logic, improving calculation accuracy for complex assemblies. Focused on geometry processing, code maintenance, and UI development to streamline workflows and support more informed design decisions.