VecGeom [1, 2] project aims at developing a high-performance library for geometry modelling, describing geometry in terms of 3D solid primitives. The library provides vectorized ray-solid intersection algorithms and other geometry-specific functionality that make use of fine-grained SIMD and SIMT parallelism.
Persistency is a very important feature for a detector geometry package: it allows improving both portability of geometry representations and performance for the initialization phase. VecGeom can currently handle reading the GDML format  and ROOT  binary representation. These implementations are partial in the current state - only reading is possible in case of GDML, while the ROOT persistency is still in development. The goal of the project is to contribute to completing these implementations and demonstrate reading/writing geometry of different HEP detectors
We propose the following steps: