Github Repo Link: https://github.com/AdrianPanGithub/HoudiniMassTranslator [github.com]

Seamless Integration between Houdini Engine and Unreal Mass Zone Graph.
Support both Zone Shape Input and Output
Support Unreal 5.3, 5.4 or later, and Houdini 20.5.278 or later.

And Unlike the citysample toolset, this zone graph translator plugin and rest other tools could Update in Real-Time in the unreal editor within a huge scale.
(Beware that only the unreal plugin is open-sourced)