 
        2D synthesis results. In each figure, the upper inset shows the input exemplar for synthesis of motion details.
            A variety of animation effects such as herds and fluids contain detailed motion
            fields characterized by repetitive structures. Such detailed motion fields are often
            visually important, but tedious to specify manually or expensive to simulate computationally.
            Due to the repetitive nature, some of these motion fields (e.g. turbulence in fluids)
            could be synthesized by procedural texturing, but procedural texturing is known
            for its limited generality.
            
            
            We apply example-based texture synthesis for motion fields. Our technique is general
            and can take on a variety of user inputs, including captured data, manual art, and
            physical/procedural simulation. This data-driven approach enables artistic effects
            that are difficult to achieve via previous methods, such as heart shaped swirls
            in fluid animation. Due to the use of texture synthesis, our method is able to populate
            a large output field from a small input exemplar, imposing minimum user workload.
            Our algorithm also allows the synthesis of output motion fields not only with the
            same dimension as the input (e.g. 2D to 2D) but also of higher dimension, such as
            3D volumetric outputs from 2D planar inputs. This cross-dimension capability supports
            a convenient usage scenario, i.e. the user could simply supply 2D images and our
            method produces a 3D motion field with similar characteristics. The motion fields
            produced by our method are generic, and could be combined with a variety of large-scale
            low-resolution motions that are easy to specify either manually or computationally
            but lack the repetitive structures to be characterized as textures. We apply our
            technique to a variety of animation phenomena, including smoke, liquid, and group
            motion.
Motion Field, Texture Synthesis, Fluids, Group Motion
