Simulation of atmospheric phenomena

Gutiérrez, Diego; Serón, Francisco J.; Muñoz, Arsenio; Anson, Oscar

doi:10.1016/j.cag.2006.05.002

Cited by 36 publications

(19 citation statements)

References 24 publications

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“…Early works in computer graphics [9], [10] simulated atmospheric phenomena by modeling the atmosphere with discrete layers. More general media is handled by effectively tracing linear ray segments at each step of a numerical solution of the differential ray equation, derived from either Eikonal equation [19], [20] or Fermat's principle [21], [22]. Similar methods [23], [24] have been proposed for modeling gravitational fields and dynamic systems.…”

Section: Piecewise Linear Propagation Pathsmentioning

confidence: 99%

“…However, the step size of linear ray tracing is inherently limited by the magnitude of media variations, hindering the scalability of these methods with physical size and complexity of the media and the scenes. Higher order numerical methods like the fourth-order Runge-Kutta are adopted to improve the efficiency [21], [22], [23], [24], [25], but the step size is still limited by the underlying media profiles. Furthermore, each advancement of the ray step with higher order numerical methods can no longer be assumed to be a straight line, making intersection tests with the scenes more complex.…”

Section: Piecewise Linear Propagation Pathsmentioning

confidence: 99%

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Tracing Analytic Ray Curves for Light and Sound Propagation in Non-Linear Media

Yeh

Manocha

2016

IEEE Trans. Visual. Comput. Graphics

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The physical world consists of spatially varying media, such as the atmosphere and the ocean, in which light and sound propagates along non-linear trajectories. This presents a challenge to existing ray-tracing based methods, which are widely adopted to simulate propagation due to their efficiency and flexibility, but assume linear rays. We present a novel algorithm that traces analytic ray curves computed from local media gradients, and utilizes the closed-form solutions of both the intersections of the ray curves with planar surfaces, and the travel distance. By constructing an adaptive unstructured mesh, our algorithm is able to model general media profiles that vary in three dimensions with complex boundaries consisting of terrains and other scene objects such as buildings. Our analytic ray curve tracer with the adaptive mesh improves the efficiency considerably over prior methods. We highlight the algorithm's application on simulation of visual and sound propagation in outdoor scenes.

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Section: Piecewise Linear Propagation Pathsmentioning

confidence: 99%

Section: Piecewise Linear Propagation Pathsmentioning

confidence: 99%

Tracing Analytic Ray Curves for Light and Sound Propagation in Non-Linear Media

Yeh

Manocha

2016

IEEE Trans. Visual. Comput. Graphics

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“…Stam and Languénou [1996] propose the use of the ray equation of geometric optics to render heat shimmering. Lately, Gutierrez et al [2006] have also applied the ray equation to render mirages and other atmospheric effects. Zhao et al [2007] simulate and render heat shimmering and mirages on the GPU at interactive frame rates.…”

Section: Related Workmentioning

confidence: 99%

“…The curved eye rays are computed as in [Stam and Languénou 1996;Gutierrez et al 2005;Gutierrez et al 2006] based on the ray equation of geometric optics. This is similar to non-linear ray tracing [Gröller 1995;Weiskopf et al 2004] that has been used to simulate gravitational lenses.…”

Section: Related Workmentioning

confidence: 99%

Eikonal rendering

Ihrke

Ziegler

Tevs

et al. 2007

ACM SIGGRAPH 2007 Papers

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Figure 1: Real-time renderings of complex refractive objects -(left) glass with red wine casting a colorful caustic, 24.8 fps. (middle) Amberlike bunny with black embeddings showing anisotropic scattering and volume caustics in the surrounding smoke and its interior, 13.0 fps. (right) Rounded cube composed of three differently colored and differently refracting kinds of glass showing scattering effects and caustics in its interior, 6.4 fps. AbstractWe present a new method for real-time rendering of sophisticated lighting effects in and around refractive objects. It enables us to realistically display refractive objects with complex material properties, such as arbitrarily varying refractive index, inhomogeneous attenuation, as well as spatially-varying anisotropic scattering and reflectance properties. User-controlled changes of lighting positions only require a few seconds of update time. Our method is based on a set of ordinary differential equations derived from the eikonal equation, the main postulate of geometric optics. This set of equations allows for fast casting of bent light rays with the complexity of a particle tracer. Based on this concept, we also propose an efficient light propagation technique using adaptive wavefront tracing. Efficient GPU implementations for our algorithmic concepts enable us to render a combination of visual effects that were previously not reproducible in real-time.

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“…The mirages were generally attributed to the graded refractive index in the air strata with a graded temperature distribution over a hot road surface, and to this date, this concept has been widely accepted in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13]. Some computer simulation work has also been published attempting to reconstruct the phenomena with seemingly successful results [14].…”

mentioning

confidence: 99%

Road surface mirage: A bunch of hot air?

et al. 2011

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The inferior mirage from road surfaces is a common phenomenon, which can be easily seen in everyday life. It has been recognized in the literature as a light refraction phenomenon due to the refractive index gradient caused by the temperature gradient in the air strata above the road surfaces. However, it was also suggested that the mirage is just a phenomenon of specular reflection at grazing incidence. Because of the lack of reasonable and quantitative evidence, the generally accepted light refraction theory has not yet been refuted. Here we show some mirror-like reflection images captured from a road surface stretch in Yujiashan North Road, Wuhan, China, when there was no obvious temperature gradient on or above the road, measured on a winter day in December 2009. This provided direct evidence to doubt the temperature induced light refraction mechanism of the inferior mirage. Furthermore, the critical grazing angle of about 0.2° to the road plane where the mirror-like reflection appears could not make the rough surface scatter incident light as a smooth surface according to the Rayleigh criterion. Therefore the phenomenon is a mirrorlike observation effect of scattering from the surface, which cannot be entirely explained by light refraction via air strata. The results demonstrate that the image-formation mechanism and the observer-based-analysis method shown here potentially offer a means of understanding a wide range of scattering phenomena from rough surfaces at grazing angle; for example, the superior mirages of unusual brightness occasionally observed over frozen lakes and the off-specular reflection phenomenon.

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Simulation of atmospheric phenomena

Cited by 36 publications

References 24 publications

Tracing Analytic Ray Curves for Light and Sound Propagation in Non-Linear Media

Tracing Analytic Ray Curves for Light and Sound Propagation in Non-Linear Media

Eikonal rendering

Road surface mirage: A bunch of hot air?

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