Expressive Visualization

Kwan-Liu Ma

We aim at improving the expressiveness of visualizations through the use of artistic inspired methods, non-photorealistic rendering techniques, and highly interactive user interfaces. Visualizations should be made by using the appropriate level of abstraction according to the purpose of visualization, and the visualizations should be perceptually effective.

Recent research results:
Dynamic Voronoi Hierarchies, Brett Wilson and Kwan-Liu Ma, UCD CS Technical Report, CSE-2005-5
Line Selection by Examples, Eric B. Lum and Kwan-Liu Ma, Pacific Graphics 2005 Conference

This work deals with representing areas of high geometric complexity using a pen-and-ink style that is clear and accurate. A minimum amount of detail is drawn while preserving, as much as possible, the original texture, color, and important boundaries. The result are more artistic looking and easy-to-understand images of real-world scenes.


Representing Complexity in Computer-Generated Pen-and-Ink Illustrations, Brett Wilson and Kwan-Liu Ma, to appear NPAR 2004, June 7-9 [pdf]

This work demonstrates highly interactive NPR for volume visualization using commodity graphics cards. The interactivity achieved allows for the exploration of a large visualization parameter space for the creation of effective illustrations.


Hardware-Accelerated Parallel Non-Photorealistic Volume Rendering, Eric B. Lum and Kwan-Liu Ma, in Proceedings of the International Symposium on Nonphotorealistic Animation and Rendering (NPAR 2002). [pdf]

Interactivity is the Key to Expressive Visualization, Kwan-Liu Ma and Eric B. Lum Computer Graphics Quarterly, 36(3):7-11, August 2002.

We have organized a SIGGRAPH 2002 course which gives a concise introduction to NPR: generation of artistic imagery and perceptually effective scientific visualization. The course delivers working knowledge of fundamental NPR techniques and some of the advanced approaches at the forefront of NPR research.


Recent Advances in Non-Photorealistic Rendering for Art and Visualization, Kwan-Liu Ma (Editor), Aaron Hertzmann, Victoria Interrante, Eric B. Lum, ACM SIGGRAPH 2002 Conference, Course 23. [Notes]

Motion provides strong visual cues for the perception of shape and depth, as demonstrated by cognitive scientists and visual artists. We introduced kinetic visualization a technique using particle systems to add supplemental motion cues which can aid in the perception of shape and spatial relationships of static objects. [More information]


Kinetic Visualization, Eric B. Lum, Aleksander Stompel, and Kwan-Liu Ma, in IEEE Transactions on Visualization and Graphics, Volume 9, Number 2, April-June 2003, pp. 115-126.

Kinetic Visualization: A Technique for Illustrating 3D Shape and Structure, Eric B. Lum, Aleksander Stompel, and Kwan-Liu Ma, in Proceedings of IEEE Visualization 2002 Conference. [pdf]

Interactive NPR techniques are used to visualize time-varying data and multifield data generated from flow simulations. Selected features are enhanced to bring out spatial or temporal relationships in the data.


Feature-Enhanced Visualization of Multidimensional, Multivariate Volume Data Using Non-Photorealistic Rendering Techniques, Aleksander Stompel, Eric B. Lum and Kwan-Liu Ma, in Proceedings of Pacific Graphics 2002 Conference. [pdf]

We have developed 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 semi-transparent paint. The resulting watercolor-style images have color coherence that results from the mixing of a limited palette of paints. The new lighting model helps to better convey large shape changes, while texture orientations give hints of less dominant features. The rendered images therefore possess perceptual clues to more effectively communicate shape and texture information.


Non-Photorealistic Rendering using Watercolor Inspired Textures and Illumination, Eric B. Lum and Kwan-Liu Ma, in Proceedings of Pacific Graphics 2001 Conference. [pdf]

We have developed methods for facilitating the visualization and manipulation of large 3D unstructured meshes. Our approach is based on identifying and displaying only the most perceptually relevant edges in the mesh.


Extracting Feature Lines from 3D Unstructured Grids, Kwan-Liu Ma and Victoria Interrante, in Proceedings of IEEE Visualization '97 Conference, pp. 285-292 [pdf]