I wrote a script to create Rigify-compatible vertex groups for an exported Genesis mesh and I thought I'd share. It should work with Genesis models exported using Collada, as well as those imported directly into Blender using .dsf scripts. For that matter, it should work with any export/import method that preserves vertex groups. It will not work with WaveFront OBJ exports, however, because that format does not preserve vertex groups.

Essentially, what the script does is maps the existing Genesis vertex groups to new groups named after Rigify bones. The bulk of the bones in the two armatures map over on a 1:1 basis, but there are some areas where either the Genesis or the Rigify armature has more bones than the other.

This script is non-destructive. It leaves the original Genesis vertex groups untouched, and creates a new set of Rigify-compatible vertex groups using the Genesis vertex groups as a guide. Because the Rigify deform bones all begin with "DEF", there are no bone name conflicts between the two armatures. What that means is that after running the script, you should be able to use the mesh with either the Genesis armature or the Rigify one (but you probably don't want to use with both at the same time...) 

You can find the script here: http://www.mediafire.com/download.php?f9h70fkhwh3f39o

Just drop it in the Addons sub-folder of your Blender 2.5 scripts folder. You can then enable it by going to User Preferences in Blender, clicking the Add-Ons pane, and clicking the checkbox next to Genesis to Rigify Vertex Group Creator. To find it quickly, type Genesis into the search box or click the "Mesh" category button on the left side.

Once turned on, a new button will appear in the properties pane of the 3D view (that's the collapsible view on the right side of the 3D view that you toggle using the "n" key). Select an imported Genesis mesh object in the 3D view then press this button:

…and the script will generate the Rigify vertex groups for you. Once you've done that, you can use Rigify the normal way, but when you parent the mesh to the Rigify armature, make sure you don't select "Armature Deform -> Automatic Weights". Because the vertex groups are already there and have proper vertex weights, use select "Armature Deform"

VERY cool. Thanks! :)

Laurie

Thank you.  It's much appreciated.

Wow -- very generous of you. Thanks!

Hello. Please can anyone remake it for Blender 2.8x version?

Someone already has.

It is called "Diffeomorphic" a complete DAZ Genesis Importer for Blender 2.9 with the option to convert to rigify or MHX for animation.