When baking, meshes are pre-processed to clean them up and converted in a format compatible with the baking process. The geometry cache is a way to preserve this pre-processed geometry in a way that is fast to reload in order to avoid redoing this operation later (unless the source mesh change).
- In Substance Designer the geometry cache is created after a first bake has been executed. The cache is then kept in memory until the baker window is closed.
- In Substance Painter the geometry cache is saved as a file with the extension assbin next to the source file after the first bake.
Reusing the geometry cache speed up quite a lot the baking process, especially when tweaking the baker settings to achieve the perfect result.