The V-Ray User Float texture allows the user to read and return a single number value from the User-Defined properties of the currently shaded object as a result. This can be useful if the same material or texture is applied to several objects in the scene, but we want to control some of its aspects (i.e. material glossiness, or a blend between two other textures inside a Mix texture etc) with User-Defined properties.

UI path:

||mat Network|| > V-Ray > Texture: Utility > V-Ray User Float

||out Network|| > V-Ray Render Elements node > V-Ray > Texture: Utility > V-Ray User Float