Modeling and rendering human hair remains to be one of the most challenging computer graphics problems. This paper presents a new interactive hair modeling system featured with a user-friendly sketching interface. With the sketching interface, any user, even a first time user, can create a hair model of his/her desired style just in a few minutes simply by interactively drawing several strokes illustrating the global and local features of the hairstyle. The result of the system is a generic geometry-based representation of hair which can be post manipulated and rendered with most existing systems.