There's plenty of modding to do without knowing C++. The SDK is needed for any addon project as it contains the documentation for making addons. You can use Vinka's Spacecraft3 .DLL for all your animation needs and never touch a C++ compiler. Check out my addons at this website, http://www.orbithangar.com/ Do an Author search for ChristopherT. None of my addons used a custom .dll. I've been with Orbiter since before it had an autopilot!