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Visibility-Guided Simplification

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[View this page in Swedish] (by Catherine Descroches on her Science Blog)

Eugene Zhang and Greg Turk
Proceedings of IEEE Visualization 2002, pp. 267-274
Boston, MA, October 27 - November 1, 2002

Paper (PDF, 1.8 Mb).

Talk slides (PPT, 3.3Mb).

Abstract

For some graphics applications, object interiors and hard-to-see regions contribute little to the final images and need not be processed. In this paper, we define a view-independent visibility measure on mesh surfaces based on the visibility function between the surfaces and a surrounding sphere of cameras. We demonstrate the usefulness of this measure with a visibility-guided simplification algorithm.

Mesh simplification reduces the polygon counts of 3D models and speeds up the rendering process. Many mesh simplification algorithms are based on sequences of edge collapses that minimize geometric and attribute errors. By combining the surface visibility measure with a geometric error measure, we obtain simplified models with improvement proportional to the amount of low visibility regions in the original models.

Figures

1. Color coding of our surface visibility measure for the Utah Teapot, a Foot Bones, Stanford Happy Buddha and Dragon, and an Interlocking Tori.

 

2. The Visibility Diagram of a 1D curve under a surrounding sphere of cameras. Point P is visible from C1 (good view, in light green) and C2 (poor view, in dark green), but not from C3. Integrating the intensity in the green channel along the vertical line (right diagram) gives rise to our visibility measure for P.

3. Simplification Results:

(1) A car motor engine model, from left to right, geometric error only, original, with visibility.

(2) A turbine blade model, from left to right, geometric error only, original, with visibility. Bottom row: overall views. Top row: close up views.

(3) A human skull model, from left to right, geometric error only, original, with visibility.