Institute for Data Analysis and Visualization

In volume visualization, users typically specify transfer functions to classify the data and assign visual attributes to each material class. Higher-dimensional classi�cation makes it easier to differentiate material classes since more data properties are considered. One of the dif�culties in using higher-dimensional classi�cation is the absence of appropriate user interfaces. We introduce an intuitive user interface that allows the user to work in the cluster space, which shows the material classes with a set of material widgets, rather than work in the transfer function space. This interface not only provides the user the capability to specify arbitrary-dimensional transfer functions, but also allows the user to operate directly on the classi�cation and visualization results.