Rotor cranks

Exactly. My understanding is that the Rotor BB converts BSA to BB30.

i.e. it has two bearing cups which screw into the threads of the BSA shell and hold the outboard bearings which accept the 30mm axle of the Rotor 3DF.

The converters on the market mainly allow you to reduce BB30 bottom brackets to 24mm (or to fit a conventional square taper BB).

The 3DF with it's 30mm spindle is not going to fit in any of those.

Kind of.

Two type of Rotor BBs - a 24mm BSA for the original Rotor 3D and the BSA30 BB that allows you to use 30mm Rotor cranks in BSA frames.

Using the BSA30 BB allows you fit 'BB30ish' cranks to BSA frames. The only thing these cranks have in common with BB30 is that the spindle is 30mm. They will not allow a 'pure' BB30 crank such as Hollowgram or SRAM Red BB30 to work on a BSA frame.

In theory, you could take a BB30 frame, insert a BB30 to BSA adapter then fit the BSA30 BB then fit Rotor 3D+/F cranks. I bet someone, somewhere has actually done this.