HairMaterial_v3
Overview
An energy-conserving, artist-friendly shader for human hair, animal fur and any other curve-based geometry.
The three most important attributes that determine the overall look:
Hair Color
This color determines the color of your hair. The shader will internally calculate the correct absorption and scattering coefficients required for the physically based hair shading model to create the final user-specified color. Primary specular highlights are not affected by this color which only affects the transmission and secondary specular highlights. Secondary specular is always darker than transmission since it travels longer inside the hair fiber and gets absorbed more.
Primary Specular Roughness
This should be your one-stop shop to control the roughness of the hair material. For physical behavior, this roughness will automatically determine what the transmission and secondary specular roughnesses should be. The secondary specular roughness is calculated as 2x and the transmission roughness is calculated as 0.5x the primary specular roughness. If desired, this connection between roughnesses can be broken based on attributes outlined below.
Transmission Azimuthal Roughness
Azimuthal roughness only applies to the transmission lobe and controls the lateral spread of energy from the hair fibers. This attribute helps control how the shader distributes energy in the hair/fur volume. Lower values will distribute the energy in a narrow band only when the light is exactly at the back resulting in darker renders whereas, higher values tend to distribute energy more evenly resulting in a more natural look. Use a value of 0.75 for human hair and 1.0 for animal fur.
Importance of max depth and max hair depth
The color of the hair comes from true multiple scattering inside the hair/fur volume. This means that the number of bounces will have a significant impact on the color of your hair. Especially for lighter/white/blonde hair, this depth should be set to a high number to allow for a more realistic hair color.
Moonray provides a separate depth variable called max hair depth that helps you control the number of bounces for the hair material. This should be set to at least 5 and for best results 10 or more for white hair.
Attribute Reference
Advanced attributes
show_multiple_scattering
Bool
default: True
show the amount of light scattered after TRT bounce, good for blonde/white hair
use_optimized_sampling
Bool
default: True
optimized sampling of all the hair lobes, results in 2x-4x speedup on average (disables individual hair lobe AOVs). When false, the look may slightly change if using biased techniques like roughness/sample clamping.
Common attributes
casts_caustics
Bool
default: False
allows continuation of caustic light paths.
presence
Float bindable
default: 1.0
controls the visibility of this object. Useful for fading an object in/out, or to specify a cut-out mask on thin single-sided geometry (eg. a complex leaf texture on a simple card).
Emission attributes
emission
Rgb bindable
default: [ 1, 1, 1 ]
the energy emitted from this material
show_emission
Bool
default: False
enables/disable emission
Fresnel attributes
cuticle_layer_thickness
Float bindable
default: 0.1
No documentation available
fresnel_type
Int enum
0 = “simple longitudinal”
1 = “dielectric cylinder” (default)
2 = “layered cuticles”
No documentation available
refractive_index
Float
default: 1.45
keep this value between [1.3,2.0] for realistic behavior (human hair is around 1.55)
Primary Specular attributes
primary_specular_offset
Float bindable
default: -3.0
offset specular highlight along hair direction (in degrees) [-10,+10], around -3 for human hair
primary_specular_roughness
Float bindable
default: 0.5
roughness of the primary specular highlight, also sets the transmission roughness to 0.5x and secondary specular roughness to 2x by default unless independent roughnesses are being used for both
primary_specular_tint
Rgb bindable
default: [ 1, 1, 1 ]
tint the primary specular highlight with this color (leave white for physical behavior)
show_primary_specular
Bool
default: True
show primary specular
Secondary Specular attributes
glint_eccentricity
Float bindable
default: 0.85
secondary specular glint eccentricity [0.85, 1], values that deviate from 1 make the hair fiber more elliptical and more glinty
glint_max_twists
Float bindable
default: 2.5
the maximum number of twists along the hair's length. More twists means more glints. Each hair strand will be randomly assigned a twist amount between [min twists, max twists]
glint_min_twists
Float bindable
default: 1.5
the minimum number of twists along the hair's length. More twists means more glints. Each hair strand will be randomly assigned a twist amount between [min twists, max twists]
glint_roughness
Float bindable
default: 0.5
secondary specular glint roughness
glint_saturation
Float bindable
default: 0.5
secondary specular glint saturation
independent_secondary_specular_roughness
Float bindable
default: 0.4
secondary specular roughness
secondary_specular_offset
Float bindable
default: -4.5
offset secondary specular highlight along hair direction (in degrees) [-10,+10], around -4.5 for human hair
secondary_specular_tint
Rgb bindable
default: [ 1, 1, 1 ]
tint secondary specular with this color (leave white for physical behavior)
show_hair_glint
Bool
default: False
show hair glint
show_secondary_specular
Bool
default: True
show secondary specular
use_independent_secondary_specular_roughness
Bool
default: False
when disabled, uses a physically correct value for secondary specular roughness which is linked to the primary specular roughness
Transmission attributes
direct_transmission_saturation
Float bindable
default: 1.0
(Non-Physical, Advanced) saturate/desaturate direct transmission highlights.
independent_transmission_roughness
Float bindable
default: 0.1
transmission roughness
show_transmission
Bool
default: True
show tranmission specular
transmission_azimuthal_roughness
Float bindable
default: 1.0
higher values create a softer look
transmission_offset
Float bindable
default: -1.5
offset transmission highlight along hair direction (in degrees) [-10,+10], around -1.5 for human hair
transmission_tint
Rgb bindable
default: [ 1, 1, 1 ]
tint transmission with this color (leave white for physical behavior)
use_independent_transmission_roughness
Bool
default: False
when disabled, uses a physically correct value for Transmission roughness which is linked to the primary specular roughness
General attributes
extra_aovs
Map
default: None
Bind this attribute to a 'ListMap' that contains references to ExtraAovMaps that specify additional outputs that can be assigned to a RenderOutput "light aov" result
hair_color
Rgb bindable
default: [ 1, 1, 1 ]
No documentation available
label
String
default:
label used in material and light aovs
priority
Int
default: 0
The material's place in an order of precedence for overlapping dielectrics. A value of 0 means the priority should be ignored. Materials with lower numbers (higher priority) "override" materials with higher numbers (lower priority). To enable automatic removal of self-overlapping geometry, a non-zero priority must be set on the geometry's material.
record_reflected_cryptomatte
Bool
default: False
Indicates whether the next reflected surface should appear in the reflected cryptomatte layers
record_refracted_cryptomatte
Bool
default: False
Indicates whether the next refracted surface should appear in the refracted cryptomatte layers