How to get rid of SSS faceting with Corona Renderer in Cinema 4D


Rendering objects with an SSS volumetric material applied can sometimes be problematic and the results may be less than desirable. 

Material Settings


This may seem like a bug or some kind of incorrect material setting but this is actually expected when rendered. Geometry is faceted in general and it's something we're not used to seeing in Cinema 4D thanks to the Phong tag. The purpose of the Phong tag is to smooth out the surface normals of an object, making it's appearance look nice and smooth. Disabling or removing the tag altogether will demonstrate heavy faceting as seen below.

 

So why do I still have faceting even with a Phong tag?

Because as mentioned, it's job is to take care of the surface normals and not the objects volume coming from the SSS volumetric material. 


How can I solve this? 

There are a few different techniques that can be used to reduce the faceting effect. Such as:

  • Increasing the segments of an object
  • Applying an SDS (Subdivision Surface) modifier with a Phong tag
  • Increasing the absorption distance of the SSS material


Solution Results:

Sphere segments: 24 (standard), Noticeable faceting.


Sphere segments: 48, Reduced faceting.


Sphere segments: 128, Virtually no faceting.


SDS (Subdivision Surface) Modifier and Phong tag. (Comparison)


Absorption amount increased from 1.97 cm to 20 cm.


For more information on SSS materials, Please see this article How to use Subsurface Scattering (SSS) Materials