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Direct3D is the base for the graphics API on both the Xbox 360 and Xbox console systems. The program is used to render 3-D graphics in applications where performance is important.

Microsoft Direct3D is a low-level graphics application programming interface (API) that enables you to manipulate visual models of 3-dimensional objects and take advantage of hardware acceleration, such as video graphics cards. It can be disabled by manipulation of Registry keys in Windows operations systems.

You can't replace Direct3d with OpenGL because it's part of your computer. However you can run OpenGL programs or games by downloading and installing a program called GLDirect. This program allows you to run OpenGL-based games and other applications using your graphics card's DirectX drivers.