Just watched this video about PBSDF and at around 17:45 he talks about the default spec being .5 Posers PBSDF doesn't load with this default and will probably throw some people off that don't understand the shader.

https://www.youtube.com/watch?v=4H5W6C_Mbck

That video is 3 years old when the PBSDF was still in it's infancy and had many bugs in it this tutorial is more current and is done by one CG Masters who really do some great course ware for Blender and it might translate into Poser work flow Blender Tutorial - Physically Based Rendering (PBR) and the Principled Node hope it helps

@Lobo3433 in the first few seconds of that video you just shared the default Specular is set to .5 just like it is in the video I shared. So what's the difference.

My apologizes I read your original post totally wrong disregard my post

I didn't watch the video through yet, is Roughness defaulting at 0.5 or 0.0 for the Blender BSDF? Maybe someone could answer back if the Poser 12 values are accurate. The readme text outlining the different fixes does mention the PrincipleBSDF being disable in build 12.0.247. I'm assuming that it is back up and active in the present build.

default on cube

Thanks for pointing this out. it made me go read the manual and Specular on this shader was not what I thought it was. I was stupidly thinking that roughness would take care of the specular, but that is just not the case.

Principled Shader Inputs

my own super shader for Poser 11 worked as per the PBSDF for blender as in the default is a glossy, plastic looking shader and roughness does what it's supposed to. That was what I expected PBSDF to do in Poser 12.