The Nissen hut was design by Major Peter Norman Nissen in 1916.
Two factors influenced the design of the hut. First, the building had to be economical in its use of materials, especially considering wartime shortages of building material. Second, the building had to be portable. This was particularly important in view of the wartime shortages of shipping space. This led to a simple form that was prefabricated for ease of erection and removal. The Nissen hut could be packed in a standard Army wagon and erected by six men in four hours. The world record for erection was 1 hour 27 minutes.
The Nissen hut was mas produced and used during Ww1 and WW2 across many theatres of the world, in addition is was licensed to the USA, Canada, South Africa and Australia for production.
Essentially where there was Allied forces you woudl find a Nissen hut and as such there is no formal design for a Nissen hut other than its semi circular shape as each hut was adapted to fit the needs of where it was located, be that an: Hospital, ammo storage, barracks, Workshops, etc…
The Nissen hut can also be used as a Quonset hut which is the American equivalent.
The Nissen hut makes a great building for for any sort of gaming board whether that be Sci0fi, alternate WW1/2, steam punk etc..