Computer Graphics Jargon:

• Illumination - the transport of luminous flux from light sources between points via direct and indirect paths
• Lighting - the process of computing the luminous intensity reflected from a specified 3-D point
• Shading - the process of assigning colors to pixels

Illumination Models:

• Empirical - simple formulations that approximate observed phenomenon
• Physically-based - models based on the actual physics of light's interactions with matter