--- title: "V-Ray Mtl Refraction" canonical: "https://documentation.chaos.com/space/VBLD/117637528/V-Ray%20Mtl%20Refraction" format: markdown --- The Refraction tab is part of the V-Ray Mtl parameters. Refraction Input Sockets You can access these sockets, when you roll out the Refraction tab of the node.  Refraction Color – Allows a color node to determine the refraction's color and intensity. Intensity is derived from the Value property of the color. Refraction IOR – Allows a float node to determine the index of refraction of the material. Refraction Glossiness – Allows a float node to determine the glossiness of the refraction. When the Mode is set to OpenPBR, the refraction properties are renamed to Transmission , they function the same way, except for Transmission Roughness , which produces opposite results from Refraction Glossiness (value of 0.00 produces mirror-like reflections). Refraction Properties Refraction Color – Specifies the refraction color of the material. Note that the actual refraction color depends on the  Reflection Color  as well. A node can also be used to control this property. See the example . Refraction Glossiness – Controls the sharpness of refractions. A value of  1.0 creates perfect glass-like refraction; lower values produce blurry or glossy refractions. A node can also be used to control this property. When the Use Roughness option in the Reflection rollout is enabled, this parameter works as Refraction Roughness (a value of 1 produces blurry reflections). Refraction IOR – Index of refraction for the material, which describes the way light bends when crossing the material surface. A value of  1.0  means that the light does not change direction when hitting the material surface. A node can also be used to control this property. See the example . Affect Shadows – This parameter causes the material to cast transparent shadows. This creates a simple caustic effect, dependent on the refraction color and the Fog Color.  Note:  For accurate caustic calculations,  disable  this parameter and instead enable  Caustics Rollout . Simultaneous usage of both  Caustics  and  Affects Shadows  can be used for artistic purposes but does not produce a physically correct result. Refract Thin Walled – When enabled, simulates thin translucent surfaces such as soap bubbles, leaves, curtains, etc. The  SSS Color  defines the backside color, while the  SSS Amount  controls the translucency effect.   Example: Refraction Color This example demonstrates the effect of the  Refraction Color parameter when creating glass materials. For the images in this example, the material has a gray Diffuse   Color and a white Reflection   Color , and the  Fresnel Reflections option is enabled. Refraction Color = 0.0, 0.0, 0.0 Refraction Color = 0.4, 0.4, 0.4 Click on the images to view them in full size Refraction Color = 1.0, 1.0, 1.0 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: in the case of transparent objects, it might be better to assign an opacity map to the material rather than use refraction. Refraction IOR = 1.00 Refraction IOR = 1.60 Refraction IOR = 2.80 Translucency Input Sockets You can access these sockets, when you roll out the  Translucency  tab of the node.  Translucency Color – Allows a color node to determine the color of the translucency.   Translucency Amount – Allows a float node to determine the translucency multiplier. Fog Color – Allows a color node to determine the Fog Color/ Scatter Radius, according to the Translucency Type.  Fog Depth – Allows a float node to determine the Fog Depth/ Scale (cm), according to the Translucency Type. Translucency Properties Translucency Type – Selects the algorithm for calculating translucency (also called sub-surface scattering). Note that Refraction must be enabled for this effect to be visible. See the example . 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. Volumetric  – Works together with the  Refraction Color  to scatter light inside the object. This type 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  – Works independently of the  Refraction Color/Glossiness  and is useful for skin, wax, marble, and other relatively opaque materials. Fog Color / Scatter Radius – Controls the absorption of the material. A node can also be used to control this property. Depth (cm)  / Scale (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. Note that it is not supported on V-Ray GPU. Scatter Color / SSS Color – Controls the scattering. A node can also be used to control this property. SSS Amount – Blends between full scattering and pure refraction. A node can also be used to control this property. Example: Translucency Type This example demonstrates the effect of the Translucency Type parameter. Note that refraction must be enabled for this effect to be visible. The Diffuse Color is red (0.9;0.225;0), and the Scatter Color is blue(0; 0; 0.9); Refraction Color (0.822; 0.822; 0.822) and Fog Color (0.697; 0.697; 0.697) are set to light gray. None Volumetric model Click on the images to view them in full size   SSS model Refraction Advanced Trace Refractions – Enables refractions for the current material. Max Depth – The number of times a ray can be refracted. Scenes with lots of refractive and reflective surfaces may require higher values to look correct. Affect Alpha – Allows the user to specify which channels are going to be affected by the transparency of the material. Color only  – The transparency affects only the RGB channel of the final render. This is the default value. Color+alpha – This mode causes the material to transmit the alpha of the refracted objects instead of displaying an opaque alpha.  All channels  – All channels and render elements are affected by the transparency of the material. Enable Dispersion – Enables the calculation of true light wavelength dispersion.  Aberration  – Allows the user to increase or decrease the dispersion effect. Lowering it widens the dispersion and vice versa. See previous: V-Ray Mtl Sheen See next: V-Ray Mtl Bump