Why can't it be FREE like 3D RAD? That's like giving a kid an empty ice cream cone, but he has to pay for the ice cream. Or giving away a potato-peeler, but you have to buy the blade. Or like giving away a free chance to buy VIRUS_INSTALLER.exe. Or like giving a kid an empty ice cream cone, but he has to pay for the ice cream. Did I say that already? Oops. I'll just go find a different program that is REALLY free.
I would say that 3DRad is your ice cream/cone.
This here (an addon) is more like the cherry or sprinkles on top of your ice cream. This is something you can make on your own - therefore, if you don't want to pay for it you don't have to. It's not like this is required for the use of 3DRad.
I really don't understand your analogies... because sadly they don't seem to work. 3DRad IS free. Another reason an addon is an addon. You ADD it ON to your project. With an addon your basically are taking someones work (with their permission). Since their doing work for you, they can make you pay them if they want. It's their property and they can do what they want with it.
@n_iron - Sounding great! Efficient, easy to use, and customizable if I read correctly. Do you have any estimated costs yet?