Scattering Mode Indicates the light scattering method in a volume of hair. Requires the Physical Material Type and Strands Geometry Type to use:
Approximate: Fall back to a simplified diffuse component to approximate hair color. This is generally acceptable for high-absorbent (dark) hair. This is the default for both Material types.
Advanced: Simulate the scattering of light through a volume of hair strands. This is important for depicting low-absorbent (light) hair. Adds the Strand Probe Volume parameter.