Thanks for the kind words, and I'm happy you're enjoying CK! :)
I use Koikatsu for the 3D modelling and scene work, which you can find on Steam. The parent company Illusion (now sadly disbanded) allows indie developers to use their assets to create projects which was amazingly generous of them. It's a real shame the company doesn't exist any more.
If you're thinking about getting into a career involving 3D modelling, though, Blender is the way to go. And if you're looking for something in-between then I can highly recommend Daz3D for its incredibly comprehensive suite of fully-rigged human models and various scene assets.