Do you have idea how they did this? I think that one way is with vellum in Houdini but any comment to discuss the way to create this stunning effect will be
Houdini: Glue constraints with vellum grains - YouTube
Houdini Tutorial: Vellum Define Pieces for Glue Constraints, file included - YouTube
Vellum - Houdini and CG tips
Vellum Welds Balloon and Glue to Animation #Houdini [Stream 2020 09 02] - YouTube