A few months ago I started a hobby project to build a custom C++ operator with the C++ SOP in order to run the Houdini Engine inside of TouchDesigner to load HDA files at runtime and leverage the powerful Houdini SOP context.
For simple geometry manipulation and simulations it runs close to real time at about 30 to 60fps.
I put together this small proof of concept video:
00:00:00 - 00:08:00: Grain simulation using collider geometry that is marshalled from TouchDesigner to the HDA and back to TouchDesigner
00:08:00 - 00:13:00: Growth propagation simulation marshalled from the HDA to TouchDesigner
00:13:00 - 00:29:00: Vellum cloth simulation
00:29:00 - 00:38:00: RBD simulation, the geometry is marshalled into the HDA from TouchDesigned and marshalled back after simulation
This is still very much work in progress and not at the top of my priority list but definitely interesting to see if there are any use cases for this or if it could even be used in production.