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Example: Reflection Color

This example demonstrates how the Reflect color parameter controls the reflectivity of the material. Note that this color also acts as a filter for the Diffuse color (e.g. stronger reflections dim the diffuse component).

Example: Fresnel Option

This example demonstrates the effect of the Fresnel reflections option. Note how the strength of the reflection varies with the Fresnel IOR of the material. For this example, the Reflect color is pure white (255, 255, 255).

Example: Reflection Glossiness

This example demonstrates how the Glossiness parameter controls the highlights and reflection blurriness of the material. Fresnel IOR = 3.5.

Example: Reflection Depth

This example demonstrates the effect of the reflection Max depth parameter.

Refract – Specifies the amount of refraction and the refraction color. Any value above zero enables refraction. Note that the actual refraction color depends on the Reflect color as well. This parameter can be mapped with a texture in the Maps rollout. For more information, see the Refraction Color example below.

Glossiness – Controls the sharpness of refractions. A value of 1.0 means perfect glass-like refraction; lower values produce blurry or glossy refractions. For more information, see the Refraction Glossiness example below.

IOR – Specifies the index of refraction for the material, which describes the way light bends when crossing the material surface. A value of 1.0 means the light does not change direction. This parameter can be mapped with a texture in the Maps rollout. For more information, see the Refraction IOR example below.

Abbe number – Increases or decreases the dispersion effect. Enabling this option and lowering the value widens the dispersion and vice versa. For more information, see the Abbe Number example below.

Affect Channels – Specifies which channels are affected by the transparency of the material.

Color Only – The transparency affects only the RGB channel of the final render.
Color+alpha – The material transmits the alpha of the refracted objects instead of displaying an opaque alpha. Note that currently, this works only with clear (non-glossy) refractions.
All channels – All channels and render elements are affected by the transparency of the material.

Max depth – Specifies the number of times a ray can be refracted. Scenes with lots of refractive and reflective surfaces may require higher values to look right. For more information, see the Refraction Depth example below.

Affect shadows – When enabled, the material casts transparent shadows to create a simple caustic effect dependent on the refraction color and the fog color. For accurate caustic calculations, disable this parameter and instead enable Caustics in the GI tab. Simultaneous usage of both Caustics and Affects Shadows can be used for artistic purposes but do not produce a physically correct result. This only works with V-Ray shadows and lights.

Thin-walled – (intended for single-surface transparent materials) When enabled and the Translucency mode is set to SSS, it simulates thin translucent surfaces such as soap bubble, leaves, curtains, etc. The SSS color defines the backside color, while the SSS amount controls the translucency effect.

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Example: Refraction Color

This example demonstrates the effect of the Refract color parameter to produce glass materials. For the images in this example, the material has a gray Diffuse color, white Reflect color, and the Fresnel Reflections option is enabled.

Example: Refraction IOR

This example demonstrates the effect of the Refraction IOR parameter. Note how light bends more as the IOR deviates from 1.0. When the index of refraction (IOR) is 1.0, the render produces a transparent object. Note, however, that in the case of transparent objects, it might be better to assign an opacity map to the material rather than use refraction.

Example: Refraction Glossiness

This example demonstrates the effect of the refraction Glossiness parameter. Note how lower refraction Glossiness values blur the refractions and cause the material to appear as frosted glass.

Example: Refraction Depth

This example demonstrates the effect of the refraction Max depth parameter. Note how too low of a refraction depth produces incorrect results. Also, in the last two examples, note how areas with total internal reflection are also affected by the Reflection Max depth.

Translucency – Selects the algorithm for calculating translucency (also called sub-surface scattering). Note that refraction must be enabled for this effect to be visible.

None – When selected, the only available parameters are the Fog color and Fog depth. Together with the Refraction color, they determine the attenuation of light as it passes through the material. In this mode, there is no subsurface scattering.

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title Click here to expand an example of the None mode
A material with white refraction color and green fog color tints the rays as they pass through the material but otherwise, there is no light scattering inside. Image Added

Volumetric – Works together with the Refraction color of the material to scatter light inside the object. It is useful for liquids and other highly transparent materials. The Refraction color and Refraction glossiness determine respectively how much of the interior of the object is visible and how rays interact with the object’s surface.

SSS – Useful for skin, wax, marble and other relatively opaque materials.

None

Fog color – Specifies the attenuation of light as it passes through the material. This option allows you to simulate the fact that thick objects look less transparent than thin objects. Note that the effect of the fog color depends on the absolute size of the objects and is therefore scene-dependent unless the Fog system units scaling is enabled. This parameter also determines the look of the object when using translucency. This parameter can be mapped with a texture in the Maps rollout. It is recommended that you use a 3D texture for the purpose. For more information, see the Fog Color example below.

Depth (cm) – Controls the strength of the fog effect. Higher values reduce the effect of the fog, making the material more transparent. Smaller values increase the fog effect, making the material more opaque. For more information, see the None (Depth) example below.

Volumetric

Fog color – Controls the absorption of the material.

Depth (cm) – Controls the strength of the fog effect. Higher values reduce the effect of the fog, making the material more transparent. Smaller values increase the fog effect, making the material more opaque.

Illumination – Determines how direct illumination is computed for sub-surface scattering.

Directional – The directional method tends to propagate more light in the direction from which the surface is lit.

Uniform – The uniform method spreads light more uniformly inside the material.

Scatter color – Controls the scattering. For more information, see the Scatter Color example below.

SSS amount – Blends between full scattering and pure refraction.

SSS

Scatter radius – Controls how far each of the red/green/components travels inside the volume.

Scale (cm) – Controls the strength of the SSS effect. For more information, see the Scale (cm) example below.

Illumination –Determines how direct illumination is computed for sub-surface scattering.

Directional – The directional method tends to propagate more light in the direction from which the surface is lit.

Uniform – The uniform method spreads light more uniformly inside the material. Note that it is not supported on V-Ray GPU.

SSS color – Determines the overall surface appearance.

SSS amount – Blends between the diffuse color of the material and the SSS effect by reducing the diffuse component of the material and replacing it with the sub-surface scattering effect.

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None

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Volume translucency mode

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SSS translucency mode

The approximation used in the VRayALMtl assumes a mostly flat surface, therefore in areas of high geometric detail and relatively large scattering radius it tends to produce inaccurate results that don't capture the details very well. In addition, the Directional mode of the VRayALMtl material may introduce unwanted color shifts.

Example: None (Depth)

This example demonstrates the effect of the Depth parameter. Translucency is set to None.