System Information
Operating system: windows 10
Graphics card: nvidia geforce 1050

Blender Version
Broken: 2.8 64 bit date: 2018-12-13 hash: 7d4d9e9dbd3
(example: 2.79b release)
(example: 2.80, edbf15d3c044, blender2.8, 2018-11-28, as found on the splash screen)
Worked: (optional)

Short description of error When applying principled volume bsdf to a sphere mesh, either modeled from a cube or uv sphere, the "Fog" is always a cube. This is problematic for making say...a planet with a volumetric atmosphere.

Exact steps for others to reproduce the error make a uv sphere or take a cube, subdivide a few times and turn up smoothness all the way. Give it a volume bsdf shader or volume scatter shader
Based on the default startup or an attached .blend file (as simple as possible).