This post is a continuation of High resolution Meshes and HD Meshes and Geografts.
A HD mesh behaves in many ways as the corresponding base mesh because it has the same topology, while the high-frequency details show up in renders. However, there are still reasons that you will want to bake normal maps from the multires modifier and apply them to the mesh at base resolution. In particular:
- Performance. The extra geometry is still present, even if it relegated to the multires modifier, which affects file size, memory consumption, and viewport responsiveness.
- If you want to export your mesh to other applications, e.g. a game, since the multires modifier is Blender specific.
Tutorials about how to bake normal maps from multires can be found on the internet, but the process is not very straightforward and quite capricious. There are a number of caveats, such as
- The material used for baking must apparently be the first one. It is not enough that it is the active material.
- The viewport levels in the multires modifier must be set to zero. This is because the difference between the mesh at the render level and viewport level is used for baking.
Moreover, DAZ meshes typically have multiple UDIM tiles, each of which must be baked separately.
For this reason I implemented a tool to Bake Normal Maps, and another to Load Normal Maps that have been baked with the first tool.