I requested a soil model from plaxis and they sent me a .dll file of the model compiled probably by fortran and it can be used directly in plaxis. However, I don't know how to open this .dll file (have tried Visual Studio % Reflector just cannot open it) as I want to know how the model is compiled. Anyone has an idea how to open it?
A .dll (similar to a .so on Linux, since this is the Linux/Mac forum) is linked executable code. There is nothing in it that can be "examined" that will tell you how it was compiled (in general), or much of anything about the source code other than routine names.