It depends on if you are molding the remaining foot or the residual limb (amputated limb). It is very hard to cast or scan either one and make a reverse duplicate of it. It is actually easy to scan the residual limb, but to make a socket that goes on the limb and is comfortable is very hard. There are soft spots on the limb and boney areas, and if the socket (what goes over the limb) is not proper it can cause ulcerations and infections that cause a lot of problems. If it is fitting well though, it can be something that allows them to walk without anyone knowing.