Hi Bill, thanks a lot. How is it decided whether it is a pure python subprocess? When I was using Process.start(), this seems to have a created a new poserpython process. You are right that C++ is easier for the things that need speed. The calculations I need are rather easy to write down in c++ too. But then there is the 32/64 win/mac problem again. Or can the boost solve this? I want to support both win and mac for my script. The c++ speedup could make my script a much better experience. its slow currently.