BRDF Models for Surface Reflection With few exceptions, the specular BRDF terms used in physically based rendering are derived from microfacet theory. In the case of specular surface reflection, e...

Microfacet Theory Many BRDF models are based on a mathematical analysis of the effects of microgeometry on reflectance called microfacet theory. This tool was first developed by researchers in the...

Microgeometry As we discussed earlier in Section 9.1.3, surface irregularities much smaller than a pixel cannot feasibly be modeled explicitly, so the BRDF instead models their aggregate effect st...

Fresnel Reflectance In Section 9.1 we discussed light-matter interaction from a high level. In Section 9.3, we covered the basic machinery for expressing these interactions mathematically: the BRD...

Illumination The $L_i(l)$ (incoming radiance) term in the reflectance equation represents light impinging upon the shaded surface point from other parts of the scene. Global illumination algorithm...

The BRDF Ultimately, physically based rendering comes down to computing the radiance entering the camera along some set of view rays. Using the notation for incoming radiance introduced in Section...

The Camera As mentioned in Section 8.1.1, in rendering we compute the radiance from the shaded surface point to the camera position. This simulates a simplified model of an imaging system such as ...

In this chapter we cover the various aspects of physically based shading. We start with a description of the physics of light-matter interaction in Section 9.1, and in Sections 9.2 to 9.4 we show h...

Scene to Screen The next few chapters in this book are focused on the problem of physically based rendering. Given a virtual scene, the goal of physically based rendering is to compute the radianc...

Many of the RGB color values discussed in previous chapters represent intensities and shades of light. In this chapter we will learn about the various physical light quantities measured by these va...