3D World’s question of the month

Getting skin to look right is tricky. It might seem as though it should be an easy task – it’s just a bit of orange, tan, olive or brown together with some good lighting, right? Well, not quite. The problem with most materials built into Cinema 4D is that they act as opaque surfaces that provide highlights that are not based upon reflection, but on the often fake-looking Specular channel. The results – as can be seen in left-hand image above – have a ‘dead’ look to them.

True, the various parts of the face have good surface colour (the lips are coloured differently to the cheeks, for example) and the lighting helps to define the form. But the result still looks as if the colour was spray painted on, or as if the model has too much makeup on, obliterating the glow that makes skin look alive.

There are two main features of Cinema 4D that will enable you to create good skin materials. The first is its capacity to layer materials effectively. The plan here is to work with multiple Luminance channels for a single surface. Although C4D’s materials system currently allows for Fusion and other inner-material layering techniques, being able to layer Luminance channels via two materials provides much a quicker way to refine the effect.

The second feature is subsurface scattering (SSS). Subsurface scattering is the phenomenon in the real world where light is able to penetrate a surface and scatter beneath it. This provides an inner glow to such diverse materials as marble, milk and skin. Although there are some limitations to C4D’s SSS implementation (it doesn’t work with global illumination, for example), it’s still a pretty snazzy tool to use and gives skin a visual volume and depth. Because you pay a rendering price for activating SSS, however, you may choose to go without (we will also look at ways to do this); but if you have the processing power, the results are worth it.

Flat skin is a problem with most 3D applications and a challenge for animators who have moved beyond the got-the-shape-and-colour- right stage. Even a lot of high-end 3D produced for film has this base-heavy look. Effective channel manipulation and material layering can bring skin tones to life, and make your renders appear to have more depth. For the illustration above, we’ve applied the technique to a simplified, cartoon-style model. This is not supplied in the support files; you should substitute your own.

Click here to download the support files (~11MB)