Skin Layers

SkinLayers material is a three layers SSS dipole implementation in the style of the old alSurface material with added features like ‘peach fuzz’ reflections and ad-hoc params to better control overall sss appearance. Works great for anything releated to subsurface scattering and remains super easy and intuitive to use. Here for this Judge Dredd’s caricature[…]

Smooth Diffuse aka Lambert-Sphere BRDF

In our journey on diffuse shading we have seen how a diffuse principled implementation better suites modern workflows than the classical Oren-Nayar implementation. The main offender on the Oren-Nayar implementation (rombo DiffuseGeneralized, Arnold Std Material) is that it is based on single scattering and so it leaks energy (diffuse gets too dark with increasing roughness).[…]

Interfaced Lambertians

Generally diffuse and specular lobes are layered making use of the Fresnel reflectance at the interface. This simply means that the diffuse lobe is multiplied by 1-Fresnel while the specular lobe is added on top. Practically it means that when Fresnel is at max (at grazing angles) we have only reflections showing up. This ensure[…]

Refractions

This shading node does refractions at boundary and then continue the ray into a volumetric medium with single scattering until it hits the back of the surface and it’s finalized into a new direction. This model is generally applicable to materials with low indices of refraction so that their translucent nature implies that a high[…]

Diffraction Lobe

Turns out that most computer graphics conductor materials (metals) don’t fit well with their measured real life counterparts. Looks like microfacet models (any reflection node you ever used..) can’t fully address the appearance of this kind of materials. Microfaceting theory models the appearance of a material at macroscopic level based on surface micro details. Situation[…]

SSS Refract

This node basically does multiple scattering refractions. When with romboRefract (or Standard Material) we do engage Scatter in the Refract (transmission) rollout we are doing instead volumetric single scattering. Multiple scattering is slower but more expressive. We can’t really render a resin statuette like this one below with single scattering. Let’s see its main parameters[…]

Walk the Walk

The SSS Random Walk node is a state-of-the-art subsurface scattering shader. We employ a new sampling strategy for random walks that takes all previouses approaches and put them together for a more effective sampling with reduced render times and great solution quality. Basically what lately did put pathtraced SSS into production is the understanding that[…]

Dipole for SSS

The SSS Dipole shader implements all the relevant dipole models for subsurface scattering available in computer graphics.. namely Standard, Better and Directional dipoles. They are of particular interest because they are better (at matching real life reference materials) than diffusion SSS and way faster than raytraced (random walk) SSS. Let’s see its GUI and main[…]