I am writing this because some time ago I took a look inside the source code of the most popular 3D open source computer graphics software called "Blender 3D". I didn't have a blog at that time and I feel like I learned a lot just by studying the source code of this program. To start things, Blender is actually written in C mostly with some parts in C++ and some parts in Python. To make matters a bit more confusing, the parts written in C actually represent the MVC design pattern. Yes, I know. C isn't really an object oriented programming language and yet here we have an application written in C that implements the MVC design pattern. So how does it implement the MVC design pattern? The application is separated into 3 main areas. The first area contains the operator and operator types. An operator type pretty much describes any action a user can execute inside the program that alters the data in the program. The operator represents an actual instance of an opera