DirectX Tweaker is a tool that acts like an interface between DirectX and/or Direct 3D and the program that originally uses the Direct 3D interfaces.
This allows to change or log all actions of the Direct 3D interface.
DirectX Tweaker serves as a host for many different plug-ins, which provide different functions each.
With this kind of modular approach it is very easy to design special modules to interact with Direct 3D.