Step 18: We’re using fast shader which is not truly volumetric but suitable for translucency of relatively thin objects. Actually we ought to be using physical shader but for this particular tutorial I’m using fast shader, I’m going to make another tutorial about physical shader. I recommend you to explore the mentalray Documentation for further information. Here is an explanation of the most used controls of the SSS shader:
• Samples: Sets how many samples from the lightmap are considered (maximum) per rendered ray, ideally, a power of two. 32 is probably the lowest useful value, 128 is plenty. However, if the scattering radii are large the sample count may need to be increased to avoid image noise.
• Ambient/Extra light: Is the ambient component or any additional diffuse light added by any shader. This light will also be included in the lightmap and get scattered like any other light source and is hence the perfect place to add any HDRI light. The HDRI light can be based on environment and occlusion maps.
• Overall diffuse coloration : This color will affect all the underlying layers (unscattered, epidermal, subdermal, back (but not the specularity) ) and is good for overall color tweaks. All diffuse colors that follow below are multiplied with this global color to yield the final result. This parameter is useful for tinting the final computed diffuse color in a desired way or to apply maps that attenuate all diffuse light.
• Diffuse color/ weight: Color and weight (a simple multiplier for easier tweaking) of the normal Lambertian diffuse lighting, which is layered on top of any underlying scattered diffuse light.
• Epidermal (top) layer scatter color/weight: are the color and weight for the front surface scattering.
• Epidermal (top) layer scatter radius: is the scatter radius in the front surface. Light will scatter this distance along the surface, in whatever units the model is made, divided by the scale_conversion parameter along the surface.
• Subdermal (top) layer scatter color/weight /radius: are the color, weight and scatter radius of the underlying sub-dermal layer. The functionality of the parameters is the same as those beginning with front_ but is for yet another layer below the top layers, representing the deeper, reddish “meaty” scattering.
• Back surface (through) scatter color/weight: are the color and weight for the back surface scattering, i.e. light going through the object.
• Back surface(through)scatter radius/ depth: represent light going straight through the object and are the scatter radius and depth for which light from the back surface is visible in the front surface. Normally, the radius and depth are set to the same value (and if the depth is not specified, it defaults to the radius) but can be set separately for increased control.
Step 20: After adjusting the Diffuse Subsurface Scattering controls we can now add specular and reflections to the object. Here is a screenshot of the Specularity and Reflection Layer controls. Start with setting the Overall specular Weight to 3 (set it high so you can see its effect more clearly. After you get the desired look you can set it low like I do ) then set Reflection Weight/ Edge weight ( leave Reflection glossiness at 1), Shininess #2, Specular Color/Weight/Edge Weight #2 and Shininess #1 to0. Then experiment with the Specular #1 and Edge narrowness controls. You’ll get something like the picture below.
Step 21: If you want you can add a Noise map to the Bump slot. Set the Number of samples to 128 to get rid of the noise.
Step 22: Ok. I’m satisfied with the look so I duplicated the material and changed the color to get variations. They can be made of berry, lemon, orange or rose.
Step 23: For the plate material I used Copper template from the Arch & Design material. And created a Mix material for the bump slot with 0,07 amount.