"Also they are usually implemented Via A plugin/extension built by makers of these third part engines." 

In the case of VRay for C4d, it was neither Maxon (C4D) nor Chaos Group (VRay), but an independent developer. Perhaps the Poser 8 api will be open enough to allow someone to build some kind of pipeline. With PoseRay, there's not a lot of work involved in getting Poser scenes into POVRay or Kerkythea. Taking advantage of the facilities of those renderers is where the work comes in IMO. Hardly ever mentioned is the fact that going back to at least Poser 4, you could export .rib format to a Renderman style renderer. Again, the transfer process is the easy part. Actually translating the shaders between render engines is rare as far as I've seen, but you're probably better off redoing them in the target engine anyway.  

I have to agree that Vue is very cool.

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