OptionalmodeDefaults to "eager".
OptionalnormalsKeep vertex normals up to date. Defaults to true.
OptionaloriginThe point subtracted from every position before it is stored as f32.
Defaults to the bounding-box centre, which keeps local coordinates small.
OptionaluvsTexture coordinates: 2 finite values per vertex, stored as f32 and read
back with views(mesh).uvs(). Without them the mesh has no UV channel and
pays nothing. Every operation keeps them aligned or drops them, undoably;
see docs/uv-channel.md. Weld keeps seams apart.
Options of Scene.addMesh.