#C4d renderman tutorial skin#

For energy to be accurate, we will set our subsurface gain to 1, this way all incoming light will be scattered.

#C4d renderman tutorial skin#

It is important to note that skin doesn't have perfect direct light reflection, so we are not using the diffuse lobe. RenderMan's Pixar Surface Material, used in all Pixar productions and many VFX studios, has 7 different subsurface algorithms which can handle these effects very well, from cartoony to realistic, including cutting-edge Path Traced Subsurface models, which we like to confusingly call PTSSS. The resulting luminance created by this complex scattering of light, gives the skin a glow of scattered light, softening the light terminator. The heart of realistic skin shading lies in Subsurface Scattering, which is the penetration and subsequent scattering of light into a surface. Thankfully all the maps are floating point EXR.ДЄs we can see in the material network below, we are not only using displacements to drive surface detail, but also bump and normal mapping, we'll go into that during our shading sub-chapter. It is important to use the highest bit depth possible for data maps to avoid compression or banding artifacts.

Let's see what our efforts look like so far.

Setting the Displacement Bound too high is inefficient and can make your render slow, so try to set this value as tight as possible. Leaving it at the default of 0.1 is usually ok, as we compute any minor discrepancies automatically. For our head, 0.2 will extend the surface bounding box 20%, which is enough to account for any slight displaced skin features such as moles. Something very important to keep in mind is the geometric attribute ' Displacement Bound' which is a crucial attribute in RenderMan for specifying a bounding box for the displacement. The resulting displacement drives a PxrDisplaceВ node which deals with the total amount of displacement.

We've chosen to set the gain to 0.003, which is enough to see a significant amount of detail added, but not enough to overwhelm the original features. The Nexture displacement map needs more fine tuning or else we'll get overly bumpy skin. We've left the gain for the main Eisko displacement map to 1, because it comes with precise values. This will come in handy, because balancing multiple displacement amounts can be tricky. Once we have everything in place, we're combining the maps with PxrDispScalarLayer, which allows us to layer multiple displacement maps and give them independent values.