CG Tech Interview #2 Physically Based Rendering

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This section serves as a summary of all the Physically-Based Rendering concepts.

Radiometry

Physics

• Photon Energy: energy that moves along a ray, assuming no wave properties. It has position e, direction d, and wave length λ.

• Radiant Energy: the total energy radiated by all the rays from any λ.

• Spectral Energy: the total energy at a specific λ.

• Flux: radiant energy a second.

• Irradiance: arrival flux at unit area (per square meter).

• Radiant Exitance: exitted flux at unit area.

• Radiance: irradiance per solid angle.

Integrators

• Solid Angle

• Irradiance by Integral Over Spheric Surface

• Irradiance by Integral Over Area

Properties

• Lambert's Law

• Radiance's Invariant Property Along A Ray

Probability

Monte Carlo Integration

• To Be Integrated:

• Estimator

p(x) is the sampling distribution function.

Sampling

Rejection Sampling

• Random On Disk

• Random In Unit Sphere

• Random On Unit Sphere

• Random On Unit Hemisphere By XY plane

• Random On Unit Hemisphere By Any Plane

Importance Sampling

• Direct Light

• Ambient Light

• MIS

• Balance Heuristic

• Power Heuristic

BSDF

BRDF

• Phong

• Blinn-Phong

, where

• Diffuse

• Torrance-Sparrow

, where

, and in Beckmann Distribution Model,

• Oren-Nayar

, where

Stochastic Path Tracing

Algorithm

• Russian Roulette

Next Event Estimation

Multiple Importance Sampling

Photon Mapping

Bidirectional Path Tracing

Volumetric Rendering

Procedures

• Absorption

• Emission

• Outscattering

• Inscattering