Hi @kchai, this sounds like some kind of bug. There shouldn't be any limitation and imported materials should be not Rhino PBR but Octane ones - one thing that may happen with Octane is complaining about texture repathing on material import, but the Octane developer said it should stay as it is as users are used to such thing and this behavior was requested earlier by users.
Please make sure you have all set up correctly:
This is how Octane repath "complaint" looks like:
And this is the result with Grass Short imported:
kchai I've notice octane render does not pick up on the PBR materials?
That being said I've realized that you are probably asking about your own model with Rhino PBR material not being rendered with Octane. If so, this is a question to the Octane developer as RN does not have any impact on what Octane can or cannot render. Eventually, if normally Rhino PBR material is supported but it is not seen when rendered in the RN distribution (very unlikely) then this is subject to fix in Octane <-> RN integration.
Please let me know what was the original intention of the question and if the above explanation clarifies anything.