Check out a tutorial on how to work in Solaris in Houdini 18.
Yuqing Chen, a SideFX intern, shared an introduction to Solaris in Houdini 18, showed some examples of creating assets, setting variants, and physical editing.
Solaris was revealed during SIGGRAPH 2019 and is a suite of look development, layout and lighting tools. It has USD at its core that helps artists create scenes out of any number of assets in one single graph. Solaris can integrate with various software.
Learn more about it here.