ROAMing terrain: Real-time Optimally Adapting Meshes

Abstract

July 1997This is a preprint of a paper intended for publication in a journal or proceedings. Since changes may be made before publication, this preprint is made available with the understanding that it will not be cited or reproduced without the permission of the author. PREPRINTThis paper was prepared for submittal to the DISCLAIMER This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. ROAMing Terrain: Real-time Optimally Adapting Meshes AbstractTerrain visualization is a difficult problem for applications requiring accurate images of large datasets at high frame rates, such as flight simulation and ground-based aircraft testing using synthetic sensor stimulation. On current graphics hardware, the problem is to maintain dynamic, view-dependent triangle meshes and texture maps that produce good images at the required frame rate. We present an algorithm for constructing triangle meshes that optimizes flexible view-dependent error metrics, produces guaranteed error bounds, achieves specified triangle counts directly, and uses frame-to-frame coherence to operate at high frame rates for thousands of triangles per frame.Our method, dubbed Real-time Optimally Adapting Meshes (ROAM), uses two priority queues to drive split and merge operations that maintain continuous triangulations built from preprocessed bintree triangles. We introduce two additional performance optimizations: incremental triangle stripping and prioritycomputation deferral lists. ROAM execution time is proportionate to the number of triangle changes per frame, which is typically a few percent of the output mesh size, hence ROAM performance is insensitive to the resolution and extent of the input terrain. Dynamic terrain and simple vertex morphing are supported.

Progressive Precision Surface Design

“…Output-sensitive computation: Our progressive decomposition algorithm performs work proportionate to the compressed (approximated) output size. This is similar to the best algorithms in more specialized settings such as viewdependent optimization [15,7], multiresolution surface editing [11,31], and multiresolution painting [2], yet provides a kind of generic "plug in" architecture that eases the addition of new manipulation operations. 2.…”

“…where the a n, j and b n, j are weights derived from the dyadic rationals (see [7]). This can be extended to include the displacements by the recurrence…”

Interoperable processing of digital elevation models in grid infrastructures

“…For the generation of viewdependent LOD the triangles are dynamically selected using the current time step´s view parameter and the view dependent error tolerance (Bao et al 2004). Examples for continuous LOD algorithm with given error tolerance are (Lindstrom et al 1996;Duchaineau et al 1997;Balmelli et al 1998;Rottger et al 1998;Gerstner 1999;Pajarola et al 2002). For out-of-core visualization Lindstrom and Pascucci (2002) describes rendering methods based on quadtrees.…”

Efficiently computing and updating triangle strips for real-time rendering

“…Duchaineau et al [10] have proposed performing incremental view-dependent sequential triangle strips for terrains. Their underlying mesh representation is a triangle bintree and as triangles are split or merged, these changes are reflected in the triangle strips for the previous frame.…”