I've made a little bit of progress. I looked in the openprop source and found a parameter to output rhino3d and solidworks macros and I was able to hack the code so that those files are now created from the GUI.
However, it looks like the macros are old and some of the commands are not supported by the latest version of rhino3d, in particular to the ExtrudeCrv command uses a PointTo mode, which the latest rhino3d doesn't have and none of the options are equivalent. The other problem is that Rhino3d isn't free and I'm using the trial version, so trying to fix the code to output proper rhino3d commands isn't worth it.
I use fusion360, which is free for hobbyists, so maybe I'll try writing a module to support fusion360 output.
I'm not sure if anybody here uses OpenProp, but it seems like a great little tool for designing efficient props. You can first run a study, which will take some basic inputs, such as size range, power and rpm range and then output a range of different propeller graphs, each with different efficiency curves. You then choose the most efficienct design, run the design mode and it produces a 3d model of the propeller that you can manufacture...that is, if you can actually get a usable 3d file, which where I'm currently stuck at.