Procedural textures are generated by Maya. In fact, all of Maya’s 2D textures (except for file and movie) and 3D textures are procedural textures.

Procedural textures are 2D or 3D plots of mathematical functions (called procedures) that have no limitation in resolution (size). You can adjust attributes for different aspects of a procedural texture to create different looks. 2D procedural textures operate much like 2D file textures in that they attach themselves to the UV coordinates of the geometry. 3D procedural textures ignore UV coordinates.