Worked on the trilinos/Trilinos repository to address a critical correctness issue in finite element method discretizations for tetrahedral meshes. Using C++ and leveraging expertise in numerical analysis, corrected the conditional logic that maps triangular faces to the C1 finite element basis by ensuring subCellDim is set to 2 rather than 1. This adjustment improved the accuracy and reliability of geometry and basis function representation in tetrahedral FEM assemblies. The work included validating geometry consistency, updating targeted regression tests, and clarifying mapping logic, resulting in enhanced code maintainability and reduced downstream errors in finite element simulations involving tetrahedral elements.