Digital artists spend much of their time manipulating real-valued GUI sliders in computer animation software. Each slider corresponds to some parameter of an analytical model that determines the appearance of a virtual object. For a given object, we call the set of all parameters controlling its visual appearance a parameter space. Shaders are a common tool in computer graphics to model the visual characteristics of a virtual object. Shaders are small programs which determine the color of each pixel on an object. The resulting image of a shader is driven by a parameter space controlled by an artist. The goal of the artist is to search the high dimensional parameter space of a shader until the desired look is achieved. Searching this parameter space my be very time consuming due to its high dimensionality. Furthermore, shaders are not always parameterized in a way that is meaningful to the artist. For example, shaders are often written by engineers with a background vastly different than the artists who will use them. An engineer might think it is natural to parameterize a noise shader in terms of “noise frequency” whereas an artist might prefer this parameter to be called “smoothness.” We present a system and an analysis of the problem of shader reparameterization. Our system allows users to add their own, personally meaningful parameters to shader and then be able to modify the result based on their own parameterization. This has the benefits of allowing uses to specify meaningful parameter names, as well as potentially reducing the dimensionality of the parameter space. In our system we implement and analyze a new novel technique called linear shader reparameterization. We also discuss(but do not implement) perceptually uniform shader reparameterization and non-linear shader reparameterization. Source code for our system can be checked out from SVN via https://subversion.assembla.com/svn/ezshade/. ∗e-mail: cab6fh@virginia.edu
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