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Optimizing line-of-sight using simplified regular terrains

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Abstract

In this work, we explore a set of techniques for speeding up line-of-sight queries whilst attempting to maintain accuracy. Line-of-sight queries, which test if two entities can see each other over a 3D terrain model, are an important operation in several applications. Given enough entities and a large enough terrain, computing these queries can be expensive. We apply reverse subdivision methods to simplify the terrain model and speed up the queries, including a novel feature-aware reverse subdivision scheme. To counteract the loss of accuracy due to simplification, we also examine the problem of where entities should be placed after terrain simplification to increase accuracy. Using iterative methods that attempt to maximize accuracy, we show that room for improvement exists over the standard projection method. Then, using residual multiresolution vectors, we develop a relocation method designed to maximize accuracy over simplified terrain models. Finally, we present a fast line-of-sight algorithm that combines these techniques with pre-existing algorithms.

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Notes

  1. In a realistic simulation, visibility can be impacted and rendered non-commutative by factors such as weather, eyesight impairments and limitations and the direction in which an entity is facing. For the purposes of this work, we ignore all factors other than the terrain that can impact visibility for either entity.

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Acknowledgments

Our thanks go out to C4i Consultants, Inc. for motivating the problem, assisting in research, and providing SRTM terrain data. Our thanks go also to the Mitacs Accelerate program for sponsoring the collaboration. Terrain map images were generated with Global Mapper software. Conceptual figures were created using Inkscape.

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  1. University of Calgary, Calgary, Canada

    Troy Alderson & Faramarz Samavati

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  1. Troy Alderson
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  2. Faramarz Samavati
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Correspondence to Troy Alderson.

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Alderson, T., Samavati, F. Optimizing line-of-sight using simplified regular terrains. Vis Comput 31, 407–421 (2015). https://doi.org/10.1007/s00371-014-0936-3

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