I made a mockup of this thing just for a demonstration. It's not perfect and not meant to be.
The model would be 3d printed or injection molded so it needs to be split into 2 halves. But with a threaded hole in the middle there where challenges to getting Invento to cooperate.
The solution I devised was to model the threads with the Thread Modeler tool available from Autodesk.
Create a new file and separate the solid body of the threads later to be reassembled in assembly mode.
Go back to the original half model, shell it and mirror.
Cut a hole the same size in the same place as the threads go.
Create new assembly with model and threads then constrain the threads to the whole.
Simplify part to re-connect everything and your done.
Apologies for the imperfections of this model. It was only created to demonstrate this process without publishing images of what I'm working on.
Made at Techshop.