An important problem in computer generated line drawing is determining which set of lines produces a representation that is in agreement with a user’s communication goals. We describe a method that enables a user to intuitively specify which types of lines should appear in rendered images. Our method employs conventional silhouette-edge and other feature-line extraction algorithms to derive a set of candidate lines, and integrates machine learning into a user-directed line removal process using a sketching metaphor ...

We present a method to aid in the generation of pen-and-ink style renderings of complex geometry. Most illustration algorithms focus on rendering a small number of surfaces with as much detail and expression as possible. These methods break down when the scene is composed of many small, overlapping details that are not individually resolvable. We propose a hybrid 2D/3D pipeline that incorporates image processing with the full scene geometry to extract regions which may require special handling ...

This paper presents a set of feature enhancement techniques coupled with hardware-accelerated nonphotorealistic 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 ...

Scientific visualization is widely used for gaining insight into phenomena through data exploration and creating imagery that can be used to illustrate these phenomena to others. Interactive rendering has long been valued in visualization as a means of facilitating more effective exploration. More recently, non-photorealistic rendering (NPR) has been applied to scientific visualization, which consists of using artistically inspired techniques for the creation of more expressive visualizations. In many cases, NPR has been shown to be more effective than photorealistic rendering in communicating subtle information about physical structures or phenomena. How the user chooses to portray a data set can have a significant effect on how accurately and efficiently a visualization communicates the information the user seeks to reveal. It is our belief that when NPR is made interactive, particularly with respect to the control of how NPR is applied, the user is able to more quickly derive expressive visualizations. ...

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Non-photorealistic rendering can be used to illustrate subtle spatial relationships that might not be visible with more realistic rendering techniques. We present a parallel hardware-accelerated rendering technique, making extensive use of multi-texturing and paletted textures, for the interactive non-photorealistic visualization of scalar volume data. With this technique, we can render a 512512512 volume using non-photorealistic techniques that include tone-shading, silhouettes, gradient-based enhancement, and color depth cueing, as shown in the images on the color plate, at multiple frames second ...

In this paper, we present a watercolor inspired method for the rendering of surfaces. Our approach mimics the watercolor process by building up an illuminated scene through the compositing of several layers of semitransparent paint. The key steps consist of creating textures for each layer using LIC of Perlin Noise, and then calculating the layer thickness distribution using an inverted subtractive lighting model ...

The paper discusses techniques for extracting feature lines from three-dimensional unstructured grids. The twin objectives are to facilitate the interactive manipulation of these typically very large and dense meshes, and to clarify the visualization of the solution data that accompanies them. The authors describe the perceptual importance of specific viewpoint-dependent and view-independent features, discuss the relative advantages and disadvantages of several alternative algorithms for identifying these features (taking into consideration both local and global criteria), and demonstrate the results of these methods on a variety of different data sets ...

In this paper we present a novel visualization technique – kinetic visualization – that uses motion along a surface to aid in the perception of 3D shape and structure of static objects. The method uses particle systems, with rules such that particles flow over the surface of an object to not only bring out, but also attract attention to information on a shape that might not be readily visible with a conventional rendering method which uses lighting and view changes ...

Motion provides strong visual cues for the perception of shape and depth, as demonstrated by cognitive scientists and visual artists. This paper presents a novel visualization technique – kinetic visualization-that uses particle systems to add supplemental motion cues which can aid in the perception of shape and spatial relationships of static objects. Based on a set of rules following perceptual and physical principles, particles flowing over the surface of an object not only bring out, but also attract attention to, essential information on the shape of the object that might not be readily visible with conventional rendering that uses lighting and view changes ...