Basically I’ve just photoscanned a fully volumetric Blender nebula using 3d Gaussian Splatting.
Links:
Nebula gaussian splats in Polycam (preview)
Nebula gaussian splats in Luma AI (preview)
Getting Started With 3D Gaussian Splatting for Windows (Beginner Tutorial)
Nebula course on BlenderMarket
More about photogrammetry workflows (including Gaussian Splatting)