Since | 20.0 |
bsdf chiang_fur(vector nn, vector tanV, float mask, float cuticle, float R_v, float R_s, float TT_v, float TT_s, float TRT_v, float TRT_s, float shift, vector absorption_coeff, float ior, float R2_v, float R2_s, vector R2_color, ...)
Creates a BSDF for computation of the physically based fur and hair model described in papers “A Practical and Controllable Hair and Fur Model for Production Path Tracing” by Chiang, “Physically-AccurAate Fur Reflectance: Modeling, Measurement and Rendering” by Ling-Qi Yan et al. Chiang Fur is an extension of the Chiang model - shader. This model considers a structural feature of fur and thick hair: the so-called medulla. Hair and fur have three main components:
Suitable only for curve geometry.
See writing a PBR shader for information on BSDFs.
nn
bumped/shading normal
tanV
tangent vector along V
mask
Masking main lobes in favour of medulla
cuticle
Modulates fresnel factor of the hair’s outermost layer
R_v
Longitudinal roughness value “v” for lobe R (section 4.1 of the paper)
R_s
Azimuthal roughness value “s” for lobe R (section 4.1 of the paper)
TT_v
Longitudinal roughness value “v” for lobe TT (section 4.1 of the paper)
TT_s
Azimuthal roughness value “s” for lobe TT (section 4.1 of the paper)
TRT_v
Longitudinal roughness value “v” for lobe TRT (section 4.1 of the paper)
TRT_s
Azimuthal roughness value “s” for lobe TRT (section 4.1 of the paper)
shift
Represents the cuticle angle, which affects the position of the specular highlight. Input range of -1 to 1 is internally mapped to -90 to 90 (eg meaning 3-degrees would be 3/90 = 0.03333)
absorption_coeff
The absorption coefficient (section 4.2 of the paper)
ior
Index of refraction (eg 1.55)
R2_v
Longitudinal roughness value “v” of extra lobe R2
R2_s
Azimuthal roughness value “s” of extra lobe R2
R2_color
Extra R2 lobes has a color input to colorize the reflection. This could be used to promote iridescence colors for example.
See also | |
bsdf |
|
pbr |
|
shading |
|