Firefly likes transmaps as much as any renderer. It takes time to calculate shadows through a transmap which is why the rumor that "firefly doesn't like it" yhas started. And yes, there IS a current problem with transparencies of any kind + IDL. But that's not really a firefly problem (or at least not JUST a firefly problem) as I understand it. It's a bug they're working on.

Momodot, I can't remember offhand if you've got Poser 8, but try Dynamic hair in that. It looks a lot better than in previous versions, apparently the renderer has been optimised for Dynamic hair now and it shows. It really looks like hair!

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.