Expanding narrow band distance field

[Marco Centin]

Hello everybody, I am experimenting with distance field computation starting from triangular meshes (big, dense, manifold, non watertight, non self-intersecting). I would like to compute a narrow-band signed distance field (I might accept to start with an unsigned distance field and compute the sign in a second step by using weighted normals). I am watching the classes implemented in the "MeshToVolume" files and I understand the general TBB-oriented design. I would like to ask where I can find an explanation of the ExpandNarrowband class. Is it feasible to expand a narrow band field through a Fast Marching Method? How would you implement tagging of frozen voxels? Use a separate grid? A custom value type?
Thank you!
Marco