At H17.5, the Atmosphere node was deleted, it is no longer available. What is a reasonable way to create an atmosphere or fog in Houdini?

I want to approach the creation of such a shader, but I do not quite understand how this is possible at the moment. Does anyone have any thoughts on this?

https://ebruneton.github.io/precomputed_atmospheric_scattering/ [ebruneton.github.io]
https://github.com/Scrawk/Brunetons-Improved-Atmospheric-Scattering [github.com]
https://www.youtube.com/watch?v=yCKhQFHybLc [www.youtube.com]

There is no reasonable way to do atmosphere in Mantra.

The Atmosphere object can still be used.

A fog shader can be assigned to the pbr engine with the render property vm_pbrshader. Doing so requires you to handle all shading for regular objects such as by calling the pbrlighting shader.

I don't consider either of these methods reasonable, but they allow a low level entry point to the shading engine to implement a custom atmosphere solution.

A regular houdini volume can be used for simple ‘lit fog’ type effects, however they are a poor replacement for the optimized solutions you have linked.

A CVEX Volume procedural might be on option that could be a bit more efficient than a regular volume.
But in my experience its also not as fast as you would hope for.