I know this is the lite forum but just wanted to let you know that version 4 takes a lot longer to process geometry at render time compared to version 3 and it might be something you want to take a look at.
I installed the update hoping that it would actually decrease render times on a project I am currently working on, but it was the opposite.
Rendering with vray Next gpu:
Railclone 3.3.1 compiling and exporting geometry takes around 30 seconds
Railclone 4 compiling and exporting geometry takes around 1.5 minutes
I did a lot of testing in order to be sure that it was in fact an issue with railclone version, rolling back and forth between the two until I finally narrowed it down to the curve steps option, I have a very simple setup, just 1 segment along 1 curved spline but my segments have very organic geometry and had to set curve steps up to 500 in order to avoid deformation, it turns out version 4 doesn't like this at all, once I lowered the curve steps the processing times went down proportionally, the times improve for version 3 as well, but not as dramatically as for version 4, so I managed to optimize my railclone setup and now I am using between 100 and 200 curve steps, got a little speed improvement but I am sticking with version 3 because its still faster than version 4.