Metalized Glass Shader and presets for DAZ Studio

Contents

Carnival Glass figurine of a Marlin splashing out of the water. Introduction Important Concepts Quick Start Shader Settings Environment Sphere Render Settings Quick Tips Known Issues

Introduction

Metal glazed glass dragon.

The AoA Metalized Glass Shader is a completely procedural shader for DAZ Studio which has been specifically designed to expand the control of reflective and refractive objects.

The intent was to create a shader which would allow for a special types of metal coated, colored glasses often called "Carnival Glass." The shader also works quite well for metals and gemstones.

The shader adds features not previously available in UberSurface or the DAZ Studio default shader. A few of the new features include opalescence, transmission of the glasses color into shadows and the control of ray trace depth and index of refraction individually for refraction and reflection.

60 presets are included covering a number of Carnival glass types, Crown glass, opalescent-transparent and stained glasses as well as diamond, amber, polished gold and antique mirror. In addition, 65 partial presets are included for mixing and matching various aspects of the shader to create hundreds of unique metals and glasses.

This product requires DAZ Studio 4.5.1.56 or higher.


Important Concepts

Comparison of an empty scene and one using an HDRI environment to provide reflection and refraction.

It is important to know that the shader and presets all require ray tracing to provide the look of glass and metal. Be sure your render settings use 3delight and have a raytrace depth of at least 2.

When we look at glass in the real world, we do not actually see much diffuse color but rather the glass's reflection and refraction of the world around it. For glass to look its best it should be completely surrounded by other scene objects to provide things for the glass to reflect and refract.

For renders that feature glass or metal objects prominently, an environment sphere with an HDRI panorama can make your glass sparkle and look outstanding. An environment sphere and 2 HDRI, interior, spherical panoramas are included for easy, instant lighting scenes for glass and polished metals.

Again, lighting of the glass itself is far less important than the lighting of the things around it or, alternatively, using the environment sphere. Most of the promo shots were created with only 1 or 2 lights in the scene and were simply used to provide shadows or extra specular highlights. Excellent renders can be achieved using no lights... only relying on the Environment dome image to provide reflection and refraction.


Quick Start

Apply the base shader - Presets

DAZ Studio screen capture showing the steps for applying the shader.

To apply a shader preset first select the object, then select the material zones you wish the shader to be applied to. The surface selection tool in DAZ Studio 4 and higher selects the object automatically when a material zone is clicked in the 3d viewport.

Holding Ctl/Cmd while clicking will allow multiple material zones to be selected at once.

A "!Reset to DS Default" preset is included should you wish to revert the material back to the standard DAZ Studio shader.

Partial Presets

Adding the trans blue to the frosted glass preset creates frosted-blue glass.

The presets in the Partials folder modify select aspects of the current shader. These can be used to mix and match or to refine your own settings.

For Example the Antique Mirror preset can be converted to an erratically iridescent, colorful, glazed glass by adding the Color Red Violet partial preset.

All partial presets that start with "Color" affect the reflection and specular colors. Those marked "Trans" affect the opacity color.

Not all partial presets will work well with eachother but experiment and see what fun combinations you can come up with.

It is recommended you first apply a shader which is close to what you desire from the Presets folder then modify it with the partial presets.


Shader Settings

UV Maps

Smoothing

Surface

Bump and Displacement

Bump and Displacement both allow for grayscale height maps to be loaded. These are the only non-procedural aspects of the shader.

The settings work in the same way as the default DAZ Studio shader with one caveat; When no displacement map is being used the Displace Min and Displace Max settings should be set to 0 rather than the default 0.10.

Reflection

Reflective spheres with different reflective raytrace depths.

Iridescence

Opalescent color changes at different rates using the Attenuation adjustment.

The iridescence settings affect the reflection and specular colors. Bright and pastel colors work best as darker colors will decrease the strength of reflections and specular highlights.

Note that at least one of the six colors must be different from the others for irregularity or noise to be visible.

Four reflective spheres with various irregularity frequencies. Reflective spheres showing how Linear, Hermite, Bezier and BSpline functions effect the changes in the color spectrum.

Noise

Four reflective spheres with various noise frequency settings.

The noise functions create additional variations in the colors of the surface's reflection and specular highlights. The effect is similar to the Iridescence Irregularity except Noise has sharper transitions and a look similar to veins of marble.

As with Irregularity, at least one of the six colors must be different from the others for noise to be visible.

Refraction

Illustration showing how to calculate raytrace depth for refraction.

Specular

The settings in this section are only affected by directional or point lights within the scene. They will not affect the highlights derived from bright spots in HDRI images applied to the environment sphere.

The color of specular highlights are calculated by color and intensity of lights multiplied by the colors in the Iridescence settings.


Environment Sphere

An example of one of the included spherical HDRIs

The included Environment Sphere prop is a simple solution to provide a 360 degree surface for providing reflections on glass and metal surfaces. The prop can be used by itself or added into existing scenes to help fill in areas where there is no geometry.

The Environment Sphere has a custom, optimized and easy to use shader. The settings can be found under the DAZ Studio Surfaces tab. Because many HDRI reflection maps tend to render a bit more colorful than low range images, a saturation control slider is included.

Any image format supported by DAZ Studio can be loaded onto the sphere's surface however the best results will come from spherically mapped, High Dynamic Range Images in floating point .tif format.

Two HDR images are included but many more are available for sale at daz3d.com or for free from around the web. Many spherical HDRIs are in .hdr format but can be converted to .tif by either using the HDRConverter script included with DAZ Studio or converting in various specialty software such as Picturenaut.


Render Settings

Max Ray Trace Depth

The most important render setting for creating images of reflective and refractive objects is Max Ray Trace Depth. This should be set as high as the the highest Reflect or Refract Ray depth setting used in the shader. Of course this can be set lower for test renders but remember that transparent glass objects will not look transparent if this setting is less than 2.

With that in mind it is not necessary to go crazy with raytrace depth. People will rarely notice if refraction and reflections are not 100% physically correct. You can often create very compelling images of complex figures using a reflect depth of 2 and a refract depth of 4 to 6 even if the true depth of the object is much higher.

Shading Rate

Shading rates of 1 or 2 are generally good for draft renders. Setting this parameter to a smaller number will produce sharper images at a cost of longer render times. I find a shading rate of 0.10 usually looks quite good for final renders.

In many cases blurry refraction and reflection will look less grainy and render faster by using a higher shading rate (smaller number) than using very high reflect and refract samples and a lower shading rate.

Pixel Filter

For most of my work I use Sinc filtering with X and Y filter widths set to 6. However, rendering highly reflective objects in a HDRI environment can sometimes produce jagged pixels around the reflections of very bright lights. This is because the renderer notices that the reflection of a light in a HDRI might be 100 or 1,000 times as bright as the area around it. To represent this extreme difference, the render filter sometimes enhances the contrast between these two areas with a black band.

In these cases the jagged band around highlights can be lessened or removed by using Gaussian filtering with a pixel width of 2 for both X and Y. The difference is subtle and may slightly decrease the overall sharpness or the render but this, combined with increasing the Reflect and Refract samples to 2 or 4 in the shader can produce some very nice images.

Renders of chrome reflections and details showing the difference between sinc and Gaussian pixel filtering.

Quick Tips

General


Known Issues

Colored shadows (AKA light transmission) only appear from lights using Raytraced shadows. Mapped shadows will render black.

Due to the way in which 3delight (and other RenderMan compliant renderers) handles refraction and depth, these shaders may not work well with the AoA Atmospheric Cameras in some cases.

When blurry reflection and refraction are used together (Eg. Frosted Glass) in large renders with high settings, DS4.5 may cause strange, # shaped, brightly colored artifacts. The cause for this is unknown but setting the Reflect Ray Depth to 2 levels lower than the Refract Ray Depth appears to eliminate the artifacts.

The Smoothing Off partial preset will not give a faceted appearance for objects with Sub-D applied and enabled. Setting the object's Resolution Level to "Base" corrects this.