A hybrid image-CAD based system for modeling realistic hairstyles.

Generating realistic hairstyles is critical in modeling human characters in computer games and feature films. State-of-the-art geometric modeling tools demand extensive user efforts and artistic skills. Image-based approaches attempt to automate the modeling process but require using special acquisition systems and/or computer vision techniques. In this paper, we present a new hybrid image-CAD based hairstyle modeling tool. We use the rich resource of hairstyle photos from fashion magazines as inputs where each hairstyle is commonly captured with a high quality and from multiple (2 ~ 3) viewpoints. We develop a sketch-based interface to allow users to draw a small number of strokes on different views and then map them to a sparse set of 3D splines. We then connect a web of splines as a guide hair surface and use it to compute a 3D orientational field within the hair volume for growing hair fibers. To further refine hairstyle models, we provide a set of tools for adjusting hair fiber length and density, perturbing hair fibers, creating wisps and curls, etc. Finally, we integrate an interactive rendering engine with the modeling modules so that the user can assess the model under realistic shading. Compared with existing solutions, our system significantly reduces user efforts and produces high quality hairstyle models consistent with the underlying hairstyle in the photo.