@ Geopapas: I've been using around 20 versions since 2.56a, so I've a different perception about what's new and not

@ Qtoken : yes, Enrico has no time to run after changes, and yes there's no point not getting latest build when using a beta
@ Steveps3 : 34454 is old, I'm using 34480 at the moment

@ Dave62 [private] : uncheck 'smooth' for your curve materials in Octane, that should do the trick.
some technical background about my understanding of the problem: during export the script gets from blender a copy of the object prepared for endering (with for instance modifiers applied and precisions levels for rendering, not viewing. With latest builds, materiasl are accessible for any type of object but 'META'. With older versions, some other kind of objects don't have their materials exposed on the prepared object. The patch uses materials from source object instead of transformed object. It may lead to problems if materials are affected by transforms, but this needs more testing than I can do alone.