Having pre-packaged Blender as a modeling/rigging environment is nice and all, but... it's 2.55. The version of Blender that came just before a major API change, and before some add-ons were added as a standard.
One of them being Corrective Shape Keys.
Why would you need Corrective Shape Keys for rigging (it's normally used for, well, corrective shapes in animation, after all)? Well, because you can use it to replace the mesh on an existing rig, without affecting *anything*. Weights stay, UVs stay, everything remains the same - as long as the mesh you're using as the key has the same vertex count and order, it just works (TM).
Plus, you can import morphs easily this way, and mix them in various ratios, generating lots of character variations easily.
But, like i've said, Blender 2.55... No Corrective Shape Keys. So, without further ado, i give you - Corrective Shape Keys addon for 2.55:
Was actually pretty easy to convert, just a few renamed methods and removing the post-2.55 module registration. Enjoy!
Corrective Shape Keys for Blender 2.55
Re: Corrective Shape Keys for Blender 2.55
PS: It's not perfect, you might get crashes, errors, etc. But it does its job.
Re: Corrective Shape Keys for Blender 2.55
Just noticed there's an import/export addon for this in the Overgrowth BlenderScript folder...
Oh well.
Oh well.