You can follow these steps to override a Maya shader in the scene view using a hardware shader, such as a CgFX shader or an HLSL shader. For more information on hardware shaders, see Work with hardware shaders.
Before you begin, you should first select Window > Settings/Preferences > Plug-in Manager and ensure that the shader plug-in (for example, CgFX or HLSL shader plug-in) is loaded.
The CgFx or HLSL shader plug-in must be loaded when Maya starts. If the Cgfx Shader or Hlsl Shader nodes do not appear in the Create Render Node window, select Window > Settings/Preferences > Plug-in Manager and enable Auto load for cgfxShader.mll or hlslShader.mll and restart Maya.