UPDATED 2018-06-12 New versions for Windows and OSX online now.
Now supports DAZ Studio shaders importing, see the following video for more info:

 

UPDATED 20180409
Philemo is hard at work with the third beta version of the PBR plugin for Carrara:
“Starting to experiment how to convert Studio shaders to PBR…”

UPDATED 20180408
A new beta is available. It adds the metallic workflow and an importer. New version is available here
More info here in the DAZ3D forums.
Updated PDF manual: PBRmanual02

Original article 20180328
Philemo has just released an early beta version of a new plugin for Carrara, PBR Lighting Model.

“I’ve started a new plugin that allows import “as-is” of PBR textures (albedo, roughness/glossiness, Ambient occlusion and metallic) such as the ones produced by Substance.
So far, it’s done for non-metallic materials (dielectric in PBR jargon).
To do that, I have implemented the Disney Principle BSDR as a lighting model. I’ve choosen it because it (or a modified version of it) is widely implemented (Blender/cycle, Appleseed, Renderman and many other included countless game engines). So, it was just time Carrara got itsown version :-). You can see here the Renderman documentation on this model (it’s the best one I’ve found so far). On top of PBR, Disney Principle add (a not convincing) subsurface, anisotropy, sheen for cloth, glossy clearcoat.”

More info in the post at the DAZ3D forum:
https://www.daz3d.com/forums/discussion/240836/beta-available-pbr-microfacets-disney-fresnel-and-tutti-quanti/p1

The updated manual is available as a PDF is here (Does not include info about the latest version DS import yet): PBRmanual02

Release note 20180328:
Beta version is out here (Windows 64 only, sorry for Mac user, I’ll try to provide an OSX version later this week).
You can find a basic documentation in this post
This is only the specular workflow. Metallic map are ignored for now. Next version will have it.

Release note 20180408
A new beta is available. It adds the metallic workflow and an importer. New version is available here.
More info here in the DAZ3D forums.

Release note 20180612
The idea behind this new feature is to exploit as much data as possible from Studio material, including Iray or other shaders type. The result may be better, equivalent or worst, depending on the quality of the material itself, the lighting in the scene and lighting model used is Studio. In the other hand, as all data will be in the shader (specular map, reflection map, normal map…), it will be easier to tweak if need be.
the DUF file is to be applied to the imported par containing vertex data (usually the “model part”).
In the effect tab of primitives, the is a new widget allowing drag & drop of DUF files. All shaders included in the Duf file will be imported, even if not used on this particular model (it’s particularly true for scene Preset shading many primitives). It’s still in Beta Stage. Please be sure to report any issue.

Example Carrara render from the new version with metallic support, using an HDRI background: