The author leveraged Houdini's Pyro simulations and Karma XPU rendering to set up the project.
Have a look at Dancing Moonlight, a mesmerizing simulation of moonlit clouds created by CG Artist and VFX enthusiast Patrick Schwalbe.
According to the artist, the simulation was set up using Houdini's Pyro simulations and Karma XPU rendering and enables one to "really get a sense of shape when the light moves across the cloud surfaces". You can check out the final composite image based on all the light angles from the video attached below:
Additionally, the author shared a collection of WiP demos captured in Houdini's viewport that demonstrate how the clouds looked during production. You can learn more about the project and check out the demos by visiting Patrick's ArtStation page.