These commands can be very attractive to save and load models in you program but have a serious pitfall: they are based on standard .NET serialization. This means that any change to the Eyeshot binaries (dll versions, dll names, type names, etc.) will invalidate all your existing files. We strongly recommend to implement your own file format (see CustomReadWrite source code sample) if you need continuity between different Eyeshot DLL versions. Another option can be to use one of the standard format supported (DWG/DXF, IGES, etc.) where applicable.