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The realistic material shading model uses several basic inputs that are summarized belowRedSDK Materials are based on the following components:

Diffusion	This is the diffuse color / texture information of the material, used in a Lambertian equation.	Image Modified
Transmission	This is the transmission color / texture information of the material. The transmission has precedence over the diffusion term for the calculation of energy preservation.	Image Modified
Reflection	This is the reflection color / texture information of the material. The reflection has precedence over the diffusion and transparency terms for the calculation of energy preservation.	Image Modified

These inputs can be modified using special parameters:

Fresnel	The fresnel option is a very powerful term that is used to modulate the amount of reflection emitted by the material based on the angle of the viewing direction with the surface. This must be turned on for all glasses materials.	Image Modified
Anisotropic reflectance	This is an extra anisotropic term that can be set to specify anisotropic reflections in the realistic material. Two anisotropy values (anisotropy in U and anisotropy in V) can be set, or texture with at least two channels (red and green) can be set instead, to define a per-pixel anisotropic information. Anisotropy values are in [0.

0f

0, 1.

0f

0]. The larger the value the wider the reflection angle.	Image Modified
Anisotropy orientation	This term defines the orientation of the anisotropy. Either a single angular value or a texture with at least one channel (red) defines the value of the rotation angle to apply to the basis used to define the reflectance of the material. Angles are expressed in radians. The read texture value is multiplied by 2PI to map the usual [0.0,1.0] range to [0.0,2PI].	Image Modified
Transmission glossiness	This term defines the glossiness value of the material. A single glossiness value or a texture with at least one channel (red) can be used to define the per-pixel transmission glossiness of the material. Glossiness values are in [0.

0f

0,1.

0f

0]. The larger the value the wider the transmission glossiness cone.	Image Modified
Transmission scattering	This is an extra absorption term that can be specified for the material transmission. It uses an out-scattering color and an out-scattering scale used to specifiy the amount of energy being absorbed along the path of a ray for each unit length crossed in the model media volume.

This is related to Volumetric effects.

	Image Modified
Reflection fog	This is fade-out term that can be specified for reflections. At a certain distance, the color of the reflection becomes equal to the specified reflection fog color, and any other visible reflection is lost.	Image Modified

Finally, the realistic material materials also features feature surface modifiers that are detailed below:

Bump map	The bump map of the realistic material affects the surface normal of the geometry at the shaded fragment.	Image Modified
Displacement map	The displacement map of the realistic material modifies the surface of the geometry that uses it

. See Displacement for details on displacement mapping

.	Image Modified

Diffusion

The diffusion model used is Lambertian, meaning that the incoming light is diffused uniformly in every outgoing direction (i.e. in the whole hemisphere around the surface hit point). It is controlled giving one color (constant over the surface or by texel using a texture). A light that illuminates a surface produces a more visible lighting if it's aligned with the surface normal.

...

Every realistic material has its own index of refraction (IOR) When transparent, the material IOR is used to deviate light rays when they travel through the volume (see figure below).

The same realistic material with two different IOR values (1.02 on the left and 1.1 on the right)
As for reflections, refractions can be glossy to simulate a wide range of materials:

The same realistic material with (on the right) or without (on the left) refraction glossiness

...

Note
The Bidirectional Reflectance Distribution Function is a function that defines how light is reflected at an opaque surface.

BRDF - Reflection

This group lets you set the glossiness parameter of reflection. The glossiness parameters control how much the reflections/transmissions are blurry. Depending on the chosen glossiness values, the results may vary a lot:

Different reflection glossiness settings
Glossiness is achieved by increasing the "Anisotropy in U" and "Anisotropy in V" parameters. If both parameters are identical, then, the reflection is isotropic. If both parameters have different values, the reflection is anisotropic, like on a CD-ROM surface or on hairs and furs.
Image RemovedImage Added
Parameters for a strong anisotropy

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When it comes to setup reflection/transmission, Fresnel support is essential. It describes the way real surfaces interacts with the light. The strength of the reflection generally depends on the viewing angle (the angle between the observer and the surface normal). For example, see how your office window panes or car paint reflect more when viewed under grazing angles rather than when front facing.

Difference between Fresnel (on the left) and non-Fresnel (on the right) reflections
This is also the place where you can turn on Caustics generation (both reflective and refractive) for your material.

A glass material with caustics turned on (on the left) or off (on the right)
A Double sided option is also available in this category to set the back-face rendering of the shape.

Feature	Description	Min	Max	Default
Options


Double sided:	Controls the front and back sides visibility	0;


	Caustics are produced by objects when light gets concentrated through reflections and refractions. Well-known examples are visible at the bottom of a swimming pool under the summer sun or a glass on a table.


Reflective caustics:	Enables/disables reflective caustics	0;


Refractive caustics:	Enables/disables refractive caustics	0;


Fresnel:	Controls the Fresnel behavior	0;


IOR:	Controls the index of refraction (IOR) of the material	-1e+038	1e+038	1.5;
Transmission scattering color:	Controls the out-scattering along the transmission ray in the material	255	255	255;
Transmission scattering scale:	Scales the effect of the transmission scattering color	-1e+038	1e+038	0;
Reflection fog:	Enables/disables Reflection fog	0	0	0;
Reflection fog color:	Controls the color of the reflection fog	0	0	0;
Reflection fog distance:	Defines the distance at which the true reflection color gets replaced by the reflection fog color	-1e+038	1e+038	3.40282e+038;

Pattern


Color shader


Diffuse color:	Controls the diffuse color	255	0	0;
Texture Shader


Diffuse texture:	Controls the diffuse texture	bmp, jpg, tif, png


Diffuse UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Diffuse UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Diffuse UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Diffuse UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Diffuse UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

Reflectance


Color shader


Reflection color:	Controls the reflection color	127	127	127;
Texture Shader


Reflection texture:	Controls the reflection texture	bmp, jpg, tif, png


Reflection UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Reflection UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Reflection UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Reflection UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Reflection UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

Transparency


Color Shader


Transmission color:	Controls the transmission color	0	0	0;
Texture Shader


Transmission texture:	Controls the transmission texture	bmp, jpg, tif, png


Transmission UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Transmission UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Transmission UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Transmission UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Transmission UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

BRDF-Reflection


	The Bidirectional Reflectance Distribution Function is a function that defines how light is reflected at an opaque surface.


Values Shader


Anisotropy in u:	Controls the material anisotropy in u	-1e+038	1e+038	0.01;
Anisotropy in v:	Controls the material anisotropy in v	-1e+038	1e+038	0.01;
Texture

Shader

Shader
Anisotropy texture:	Controls the anisotropy texture	bmp, jpg, tif, png


Anisotropy UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Anisotropy UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Anisotropy UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Anisotropy UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Anisotropy UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

BRDF-Orientation


Rotation Shader


Anisotropy rotation:	Controls the rotation of the anisotropy	0	1	0;
Texture Shader


Anisotropy rotation texture:	Controls the orientation of the anisotropy	bmp, jpg, tif, png


Anisotropy rotation UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Anisotropy rotation UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Anisotropy rotation UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Anisotropy rotation UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Anisotropy rotation UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

BRDF-Transmission


Angle Shader


Transmission glossiness angle:	Controls the glossiness angle of the transmission	0

1

0;

	1	0;

Texture Shader


Transmission glossiness texture:	Controls the transmission glossiness texture	bmp, jpg, tif, png


Transmission glossiness UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Transmission glossiness UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Transmission glossiness UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Transmission glossiness UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Transmission glossiness UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

Bump


Texture Shader


Bump texture:	Controls the bump texture	bmp, jpg, tif, png


Bump UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Bump UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Bump UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Bump UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Bump UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

Displacement


Texture Shader


Displacement texture:	Controls the surface displacement	bmp, jpg, tif, png


Displacement height:	Controls the amount of geometry displacement	-1e+038	1e+038	0;
Displacement offset:	Controls the relative position of displacement	-1e+038	1e+038	0;
Displacement UV matrix U offset:	Controls the translation of the texture along U	-1e+038	1e+038	0;
Displacement UV matrix V offset:	Controls the translation of the texture along V	-1e+038	1e+038	0;
Displacement UV matrix U tiling:	Controls the number of texture repetitions along U	-1e+038	1e+038	1;
Displacement UV matrix V tiling:	Controls the number of texture repetitions along V	-1e+038	1e+038	1;
Displacement UV matrix UV rotation angle:	Controls the rotation angle of the texture	0	360	0;

Material	IOR
Acetone	1.36
Air	1.0
Alcohol	1.33
Chromium Oxide	2.7
Copper Oxyde	2.7
Crystal	2.0
Diamond	2.42
Emerald	1.57
Ethyl Alcohol	1.36
Glass	1.5
Glass, Crown	1.52
Glass, Heaviest Flint	1.89
Glass, Heavy Flint	1.65
Glass, Light Flint

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