So the technique is called Shell Mapping and I got the basics from:
Interactive Smooth and Curved Shell Mapping
https://www.cg.tuwien.ac.at/research/publications/2007/JESCHKE-2007-ISC/
The technique as documented starts with Geometry Shaders which is a really bad idea so I kept things simple and did all the pre-processing on the CPU when meshes were imported. These days I'd look at doing it on-demand in a Compute Shader. Preprocessing steps are:
- Parameterise a heightmap for your mesh.
