Amazing! I’ve just known Sverchok Blender add-on which enables you to generate 3d object using node-based editor, like Grasshopper in Rhinoceros. Grasshopper is a so famous plugin of Rhinoceros and very useful, but use of Grasshopper is limited to windows os. Sverchok is one of Blender add-on, so of course you can use it on your own mac!
This is the introduction movie created by authors of the addon.
How to use it
Firstly, download Sverchok plugin and place downloaded files to your blender addon directory where you place other addon files. After that, launch the blender and enable Sverchok addon at “User Preferences” dialog.
Finally, you can use Scerchock node editor. You can place nodes from tool shelf located on the left edge of node Editor (If you can not see tool shelf, hit “T” key to see it) or hit “Shift-A” to get the node lists on your screen.
I peruse this addon and create some node module which is useful for generating model data!