Physically based rendering

Differences in surface roughness and reflection appear in response to light.

Visual traits

• Material-specific reflection
• Roughness
• Lighting coherence

Expected changes

• Reflection differences among surfaces are more likely to be visible
• Materials are more likely to appear responsive to changing light

Definition

It determines appearance through material properties such as roughness, metallic response, and reflection in relation to lighting. It differs from a particular software product or photorealistic finish alone.

In more detail

It organizes an appearance in which a material reads consistently under different lighting. Subject, composition, and render engine remain separately selectable.

Includes

• Material-property and lighting interaction

Excludes

• A particular render engine
• A claim that an image is a photograph

What this does not imply

• A particular software product
• Ray tracing
• A particular subject

Variability

Results vary with both material parameters and lighting.

Usage

• Relate material properties to lighting
• Specify subject and render engine separately

Distinguish similar expressions

• Add ray tracing when a light-transport method is required

Typical uses

• Show distinctions among metal, cloth, and stone surfaces

Possible failure modes

• Different materials show identical reflection
• Lighting and surfaces do not cohere