The Dielectric Physical Phenomenon Shader is a

shader In computer graphics, a shader is a computer program that calculates the appropriate levels of light, darkness, and color during the rendering of a 3D scene—a process known as '' shading''. Shaders have evolved to perform a variety of s ...

used by the

LightWave LightWave 3D is a 3D computer graphics program developed by LightWave Digital. It has been used in films, television, motion graphics, digital matte painting, visual effects, video game development, product design, architectural visualizatio ...

and

Mental Ray Mental Ray (stylized as mental ray) is a production-quality Ray tracing (graphics), ray tracing application for 3D rendering. Its Berlin-based developer Mental Images (firm), Mental Images was acquired by Nvidia in 2007 and Mental Ray was discon ...

3D rendering engines. It is based on a dielectric model of physics, which describes how

electromagnetic fields In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...

behave inside materials. The dielectric shader is able to realistically render the behavior of light rays passing through materials with differing

refractive indices In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...

, as well as attenuation of the ray as it passes through a material. The shader uses

Fresnel equations The Fresnel equations (or Fresnel coefficients) describe the reflection and transmission of light (or electromagnetic radiation in general) when incident on an interface between different optical media. They were deduced by French engineer and ...

to simulate reflectance and transmittance of light passing through the dielectric interface, as well as using

Snell's law Snell's law (also known as the Snell–Descartes law, the ibn-Sahl law, and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing th ...

to determine the angle of refraction. In addition Beer's law is used to determine absorption of rays passing through dielectric materials. Two types of dielectric interfaces are supported: *dielectric-air between a dielectric material and air. *dielectric-dielectric between two dielectric materials.

Gallery

Image:Alcool_Di_VertigoSP.jpg, Frosted glass using Dielectric and Spekle bump mapping. Image:C_S.jpg, Solid glass letters with an IOR of 1.333. Image:Le_doublot.jpg, Two solid dielectric objects overlapping to show the refracting effect.

References

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