# 原理化毛发 BSDF节点¶

Melanin concentration选项下的原理化毛发 BSDF节点界面。

Tip

## 输入选项¶

Hint

$\sigma_{a} = \frac{\ln(Color)} {\left(5.969 - 0.215\beta_{N} + 2.532\beta_{N}^{2} - 10.73\beta_{N}^{3} + 5.574\beta_{N}^{4} + 0.245\beta_{N}^{5}\right)^{2}}$

Hint

$melanin\_qty = -\ln(\max(1.0 - Melanin, 0.0001))$

Hint

$\begin{split}\sigma_{a} = eumelanin * \left[\begin{matrix} 0.506 \\ 0.841 \\ 1.653 \\ \end{matrix}\right] + pheomelanin * \left[\begin{matrix} 0.343 \\ 0.733 \\ 1.924 \\ \end{matrix}\right]\end{split}$

Hint

Absorption Coefficient

Specify how much the glints are smoothed in the direction of the hair shaft. Too low values will smoothen the hair to the point of looking almost metallic, making glints look like Fireflies; while setting it too high will result in a Lambertian look.

Hint

IOR 折射率

Hint

Hint

## 属性¶

Color Parametrization

Direct Coloring

Melanin Concentration

• White (Melanin $$0$$)

• 亚麻色 (黑色素值设为 $$0.25$$)

• 淡红色 (黑色素值设为 $$0.5$$)

• 棕色 (黑色素值设为 $$0.75$$)

• 黑色 (黑色素值设为 $$1$$)

Absorption Coefficient

BSDF

## 参考文献¶

CBTB16(1,2,3)

Chiang, M. J. , Bitterli, B. , Tappan, C. and Burley, B. (2016), A Practical and Controllable Hair and Fur Model for Production Path Tracing. Computer Graphics Forum, 35: 275-283. doi:10.1111/cgf.12830

EFHLA11

d'Eon, E. , Francois, G. , Hill, M. , Letteri, J. and Aubry, J. (2011), An Energy‐Conserving Hair Reflectance Model. Computer Graphics Forum, 30: 1181-1187. doi:10.1111/j.1467-8659.2011.01976.x