UberSurface Tutorial, Part 1: Understanding UberSurface
1. UberSurface and other shaders
UberSurface is one of the most powerful shaders available for DAZ Studio...and the best part is, it’s free (it comes with the software). Using UberSurface, you can render realistic skin, hair, fabric, and other materials.
This tutorial covers UberSurface’s basic functions and some of the many more advanced or esoteric ones.
UberSurface is often compared to (and sometimes confused with) certain other shaders:
- HumanSurface (also known as the Elite Human Surface Shader, EHSS, or HSS) was the predecessor to UberSurface, and has much in common with it. You could say that UberSurface is HumanSurface with some additional features (these extra features are listed in Section 4, “More Advanced Functions”). Any tutorials for HumanSurface that you find should also work with UberSurface, with similar results.
- UberSurface2 is a more advanced version of UberSurface. Perhaps the most significant improvement is the ability to handle layered materials. It is available for purchase from the DAZ 3D store.
- UberHair is an add-on for UberSurface
- SubSurface Shader Base is the new (released earlier this year) shader by Age of Armour. It’s available for free with DAZ Studio and contains a more advanced SubSurface Scattering algorithm. A tutorial for the SubSurface Shader Base is available here.
- pwSurface 2 is an alternative to UberSurface, made by PoseWorks instead of omnifreaker, and available from the DAZ store. The functions are mostly similar, but usage is somewhat different.
2. Basic Functions
These same dials exist for many of the shaders commonly in use, including the DS Default Shader. Functionality is similar, though some differences between the specularity model of UberSurface (and HumanSurface) and that of the DS Default Shader deserve mention.
There are other resources for learning what these terms mean, but here are a few quick reminders/rules of thumb:
- A matte surface will have a high diffuse value and a low specular value
- A shiny surface will have a high specular value (it may have a high diffuse value too)
- Specular strength controls the intensity of the highlight; glossiness controls the size of the highlight (with glossier surfaces having smaller highlights)
-Bump creates the illusion of roughness (or bumpiness) while displacement actually changes the geometry to increase roughness (or bumpiness)
Please note that the glossiness setting works differently in UberSurface than it does in the DAZ Default Shader. If you are converting an object to UberSurface, you may need to drop the glossiness value significantly to achieve similar results (for instance, DS Default Shader glossiness of 50% is similar to UberSurface glossiness of 4%, and DS Default Shader glossiness of 85% is similar to UberSurface glossiness of 50%).
3. Advanced Functions
This is particularly useful for textures that are seamless tiles. As the values get higher, the pattern gets smaller and repeats more frequently. You can adjust the horizontal and vertical tiling separately.
This is perhaps one of the more obscure and arcane settings, but it can really help boost the realism of some types of material, including water and glass. It’s related to reflection and controls how reflection is affected by the viewing angle. For an illustration of how fresnel works, see the renders on this page (note: not DAZ Studio renders--I think they were done in Cinema4D), comparing fresnel reflection to reflection without the fresnel effect.
Some surfaces like velvets and other fabrics, and also human skin, have very fine hairs or fibers that catch the light, especially when viewed at an angle. With the right settings, this can greatly increase the realism of skin and clothing.
For use on skin, it’s worth considering that vellus hair is not evenly distributed on the human body--there’s none on the lips, palms, soles, etc.--and it’s more noticeable on women and especially young children.
Fabrics differ too--velvet itself, of course, will have show a very strong velvet effect, while silk, for instance, will have little to none. Most other natural fabrics such as cotton, wool, and linen, plus some artificial microfiber-type textiles, will benefit from this effect.
- Subsurface Scattering
Subsurface Scattering refers to how light can penetrate a surface and scatter within it rather than merely bouncing off.
First, let's look at a few common myths about SubSurface Scattering (SSS):
Myth: Renders with SSS are more realistic than renders without SSS
Reality: This is often true but not always--SSS is one of many factors that contribute to realism, and a render with SSS that’s been set up poorly will probably look less realistic than one with no SSS at all. And of course, it's not a good idea to apply SSS to surfaces that are not at all translucent.
Myth: Poser has SSS but DAZ Studio does not.
Reality: This may have been true at one time, but not anymore. DAZ Studio has had SSS capabilities for years.
Myth: In order to use SSS in DAZ Studio, you need to use the SubSurface Shader Base by Age of Armour.
Reality: While the SubSurface Shader is an excellent tool for achieving a SSS effect in DAZ Studio, it’s not the only shader capable of SSS. UberSurface, UberSurface2, HumanSurface, and pwSurface2 all have SSS functionality as well. One advantage of the SubSurface Shader is that it allows for automatic backscattering which is difficult to achieve with other shaders. Backscattering refers to the way that ears and other translucent objects seem to glow when lit from behind, due to light passing through them.
The first time SSS was used on a CG character in a major film was in The Two Towers (2002) for the character of Gollum. The lack of SSS prior to this was a big part of the reason why CG characters tended to look plasticy and unrealistic.
The more translucent the surface, the stronger the SSS effect will be. This means that pale-skinned characters will exhibit more SSS than darker-skinned characters.
In human skin, the SSS color should be orangish or reddish due to the presence of blood vessels under the skin. If the creature you’re rendering has green blood, be sure to change the SSS color accordingly!
If you want to have a deeper understanding of how the effect works, here’s the groundbreaking paper that enabled the technology behind SSS in 3D rendering (the paper is very technical in nature, so it might help to have a math, physics, or engineering background).
4. More Advanced Functions
These features are what distinguishes UberSurface from HumanSurface. UberSurface has them, HumanSurface does not.
- Anisotropic Specular
Don’t be scared off by the techspeak...this is a very useful setting. Basically, when this is turned on, the specular reflection will be directionally dependant (the reflection is stretched along one axis). Hair, for instance, tends to look wrong when the specular reflection is not anisotropic. Brushed metal is another example, as well as other surfaces with parallel grooves.
- Diffuse Roughness
It’s easy to see how specular reflections are handled differently by glossy surfaces vs. matte surfaces. But the diffuse response will be affected too, and this setting gives some additional control over that. Very matte surfaces should have a low diffuse roughness value so that the diffuse response is broad; shiny surfaces might need to have a higher diffuse roughness value.
Fantom is useful when you want something to be invisible but still cast a shadow or appear in a reflection. For another use, see the Fantom Occlusion section of my Hair Tutorial for DS4 Users]hair tutorial.
Turning raytracing OFF on surfaces with transmaps (opacity maps)--hair, for instance--may make your renders faster, especially when using UberEnvironment or other lighting with Ambient Occlusion. A little realism may be sacrificed as a result, but often it’s hard to tell the difference. It’s kind of the opposite of Fantom: the object will be visible, but won’t cast raytraced shadows or appear in reflections.