So a couple different things, if I miss some stuff, it's not intentional.
First, I ran across this video from s3d just this week that I never knew about despite using it for years:
https://www.youtube.com/watch?v=g1V-5aA03dQ
Since that's not what we're really talking about here, I would love those features. But there are full programs trying to come up with a way to do this and there are TONS of other features we need added to S3d. If there's a way of adding this stuff to S3d without charging $1k for the program with an ongoing cost, I'd certainly love it.
But to anyone trying to look for these split features without using netfabb (I was using netfab yearrrsss ago when I was doing more splitting and it was painful), go to meshmixer. It's free. Further, here's a bunch of programs that will let you do that stuff:
https://pinshape.com/blog/learn-how-to- ... 3d-design/
Do feel free to message me if that link helps you or if there's other ideas (I started going down that road but other work not requiring all that has come up).