Hi Peter, well T-splines is a plug-in written by a 3rd party that adds stuff to Rhino.

Plug-ins are built to a specific system - they use various services from the host application and are tightly connected with how the host mechanism is set up (like it's UI, how commands work, etc...) so anyway that's why you can't run t-splines directly on MoI.

It's kind of like how you can't take a water pump out of one car and just stick it in any other car - the connections and how a part like that fits into place are not identical between every kind of car.

- Michael