This paper presents a set of feature enhancement techniques coupled with hardware-accelerated non-photorealistic rendering for generating more perceptually effective visualizations of multidimensional, multivariate volume data, such as those obtained from typical computational fluid dynamics simulations. For time-invariant data, one or more variables are used to either highlight important features in another variable, or add contextural information to the visualization. For time-varying data, rendering of each time step also takes into account the values at neighboring time steps to reinforce the perception of the changing features in the data over time. With hardware-accelerated rendering, interactive visualization becomes possible leading to increased explorability and comprehension of the data.