This task is for figuring out whether to map the idea of attribute grids to the attribute concept, and if so, how to do it.
Here's some background I wrote about in chat:
>One of the level set nodes we could implement is a fracture node that splits up one level set into many pieces based on some other surface. The output is an arbitrary number of grids.
>For meshes this is easy-- just have multiple "islands" in the mesh! But here we cannot just combine the grids. Theoretically each grid could be stored in a separate instance on the geometry, but they are not really instances, so that's a hack.
>I think you shouldn't have to choose grid output names in this case, and if you pass it to another node it would just operate on whatever grids were part of the volume. Very quick, and not complicated!
>On the other hand, a major use case for multiple grids is when they basically share the same topology but encode different information, like heat, pressure, velocity, etc.
>In that case you really want to be able to choose a grid when generating points, or easily split the density grid from the volume. Both are fine I think, splitting is a more general solution.
>In the first case, grids don't correspond to attributes at all, they're just a bunch of different shapes, e.g. cloud puffs or surfaces, etc.
>In the second, they align well to attributes, except that there is no "main" attribute like position, unless that is the density grid
In D12100 I implemented volume to mesh transfer for all grids in a volume, and "Distribute Points in Volume" will have the same decision.