Direct3D (D3D)
Microsoft's proprietary 3D API. It was originally written by Render``Morphics and was acquired by Microsoft in 1995. Direct3D is available only on the Windows series of operating systems. Direct3D has captured the mindshare among most Windows developers, mostly due to the complete lack of any viable alternatives on the PC platform. Microsoft has been pushing Direct3D over OpenGL for many years, sometimes against the opposing wishes of Windows developers.