@lexicolopolis Only downside of modeling the cracks is that you can’t just slap on a Multires modifier without making some extra edges in the lowpoly. It’s as Kent said, the dirty way 😉
My workflow is:
1. Put bevel on lowpoly so sharp edges stay sharp when subdivided.
2. Subdivide the mesh enough to have a smooth model.
3. If everything is smooth enough, go to sculpt mode and remesh it with a small enough face size, the result will be a mesh with nice even faces so when sculpting you have the same behavior in all directions, so no stretching.
4. Add Multires modifier and start sculpting, a lot of scraping, adding seams, pinching, more scraping and so on