Rapid Prototyping is so much more than Additive Manufacturing. There is now no need to wait 4-5 weeks for machined parts – there are now companies who will routinely machine parts in 7-10 or even 2-3 days depending on your budget.
Entrepreneurs need to have a good handle on both development & production costs up-front to build a robust business case. But how is it possible to get production costs at the very beginning of development before the product has been designed?