CYCLES - making alpha masks inside of blender with nodes


is this possible to load cutout image and, using same uv map , turn this image into BW mask with nodes?
this way we could adjust mask in realtime and without need for ps/gimp/alike…

it may be easy - i dont know, but im pretty new to nodes system…


Check out the speaker tutorial on Blender Cookie.

But the Node setup: [ATTACH=CONFIG]169742[/ATTACH] will allow you to create a B&W image of the particular item you want. Only copy the item you want as white to a seperate layer.

Then save as an .ext

i have done it by trial / error - looks useful and makes things far easier and faster to work with
all u need is a jpeg with cutout image and white background