Thats Brilliant - There is even an Excel calculator to generate the dimensions for the Pattern. This looks like a very promising project. I know where I can get some Cotton Ventile fabric roll seconds to save some money. I think I'll make it a double layer, DPM ventile on the outside and OG ventile on the inside. This will allow the Bod-i-bag to also double up as an emergency breathable and semi-waterproof bivi bag also.