Material Editor Dialog (Advanced Mode), Transparency Tab

Contains controls for setting a material's transparency.

Setting	Description
Efficiency	Lets you define the efficiency of the material directly, either by adjusting the slider or by typing a value in the associated field. Efficiency is defined as the total percentage of incoming light that is re-transmitted back into the environment. This includes diffuse and specular reflections, as well as the light transmitted through opacity and translucency. When the efficiency is 100% or greater, it displays in red, warning that the material is unrealistic. Typical materials in the real world generally range in efficiency from 30% to 70%.
Lock icon (efficiency)	Clicking the icon turns on or off the lock. If on (locked), the efficiency of the material is locked such that modifying the diffuse, specular, opacity, or translucency components will automatically adjust the other components to maintain the efficiency value. If off (unlocked), modifying the diffuse, specular, opacity, or translucency components changes the efficiency value, but does not automatically adjust the other components.
Opacity icon	Lets you define an opacity color or to link opacity to other settings. Link to specular — Links opacity to the specular settings. Link to diffuse — Links opacity to the base color/map. Color map — The opacity color is defined by a color map. Click on the icon to select or modify the color map. Custom — Lets you select an opacity color, which is displayed in the icon. Click on the icon to define or modify the custom color.
Opacity scale	Defines the percentage of incoming light that is not transmitted directly through the material. Values may range from 0 (Clear) to 100 (Opaque) and may be typed in the text field, or adjusted using the slider.
Opacity map icon	Lets you link Opacity to a map or other settings. When Opacity is set to zero the material is transparent regardless of the map. As the opacity changes, the transparency is a result of the combination of the opacity value and the contents of the map. When Opacity is set to 100, the value of the map is used to determine the opacity such that white pixels are fully opaque and black pixels are fully transparent. Material with opacity map applied Click the arrow icon to open a menu with the following options: On — A pattern map, if defined, will be used with Opacity. When you pause the pointer over the pattern icon, you can see the name of the current pattern map. Click the icon to open the Open Image file dialog, which lets you select an image file for use as a pattern map. After selecting the image file, the Map Editor dialog opens, which lets you edit the settings for the pattern map. This includes options for selecting an image file, a procedure, or a gradient. Off — Turns off Opacity mapping. Link to pattern/bump/specular/reflect — Links Opacity mapping to the current pattern or bump map, or to the setting for specular or reflect.
Refract	Refract is only available when Opacity has a value less than 100. Sets the index of refraction, which controls how much the light changes direction as it passes through a transparent material. Values range from 0.1 to 3.0. A value of 1.0 causes no change of direction. Values can be typed in the text field or selected from the option menu which opens when you click the arrow icon. This menu provides standard values for refraction, such as Air, Water, Plastic, Glass, Crystal, Diamond.
Dispersion	Sets the amount of light separation on transmission through a material, such as occurs when light passes through a prism. Click the down arrow to display a list of common physically-correct dispersion values. Note: To render dispersion effects you will need to use Direct Photon Mapped Caustics.
Roughness icon	Lets you define a custom roughness value or link roughness to specular.
Roughness	Defines the percentage of roughness displayed on the material. Values may range from 0 to 100. You can type a value in the text field or use the slider. Simulates the effect of frosted glass. The higher the roughness value, the rougher the surface, resulting in refractions that are more blurred.
Roughness map icon	Lets you link Roughness to a map or other settings. Click the arrow icon to open a menu with the following options: On — A refraction roughness map, if defined, will be used. When you pause the pointer over the icon, you can see the name of the current pattern map. Click the icon to open the Open Image file dialog, which lets you select an image file for use as a map. After selecting the image file, the Map Editor dialog opens, which lets you edit the settings for the map. Off — Turns off roughness mapping. Link to — Drop-down menu lists many options to which you can link roughness mapping.
Blur Refractions	When on, items visible through the material are blurred. Roughness of the blurry refraction is controlled by the refraction roughness value.
Refraction Rays	Sets how many refraction rays are used to create the blurring. Increasing the number of rays can improve the image but takes longer to render.
Exit Color	Sets an Exit Color for refraction rays. Allows you to set refraction rays to a reasonable termination point improving performance in scenes with many transparent objects without producing unnatural black pixels.
Absorption Distance	The distance light has to travel through the surface before it acquires the transparent color of the surface. Colored transparent surfaces do not often exhibit even coloration. Thin areas appear colorless while thicker areas tint with color. The Absorption Distance controls this effect, setting how far a ray must travel to get 100% of the transparency color. The falloff is determined by Beer’s Law, just as in the real world.
Dissolve	Enables the object using this material to be faded from view, higher values produce more fading. A Dissolve value of 100 means the object completely disappears from view when rendered.
SubSurface icon	Lets you define a subsurface color or to link subsurface to other settings. Link to specular — Links subsurface color to the specular settings. Link to diffuse — Links subsurface color to the base color/map. Color map — The subsurface color is defined by a color map. Click on the icon to select or modify the color map. Custom — Lets you select a subsurface color, which is displayed in the icon. Click on the icon to define or modify the custom color.
SubSurface	Controls the amount of light that illuminates the side of the surface opposite the light source. That is, the percentage of incoming light that is transmitted through the material and scattered in all directions as it exits the material.
SubSurface map icon	A transparent color map can be used to vary the transparent color of a surface. In addition to selecting a color or map, you can also link the transparent color to either the diffuse or specular colors. On — A pattern map, if defined, will be used with subsurface. When you pause the pointer over the pattern icon, you can see the name of the current map. Click the icon to open the Open Image file dialog, which lets you select an image file for use as a map. After selecting the image file, the Map Editor dialog opens, which lets you edit the settings for the map. This includes options for selecting an image file, a procedure, or a gradient. Off — Turns off subsurface mapping. Link to pattern/bump/specular/reflect/opacity — Links subsurface mapping to the current pattern or bump map, or to the setting for specular, reflect or opacity.
Front Weighting	The Front Weighting setting with bias the subsurface scattering sources towards the light source. At 50%, they scatter evenly in both directions. At less than 50%, they scatter towards the light; less than 50% they scatter away from the light.
Scattering Distance	This value determines how far the light must travel through the surface before it is tinted by the subsurface color.
Samples	Sets the number of samples used when subsurface shading. Higher values result in better images.

Material Editor Dialog (Advanced Mode), Transparency Tab

Material with opacity map applied