Refractions are caused by the bending of light through different densities of materials that allow light to pass through them, such as glass, water, etc. This page gives an overview of the three refraction render elements that may be output through V-Ray and how they are used in compositing. Specific usage for each of these refraction elements is linked in the Overview.
When a material has a refraction value (as set through the Refraction Color and Refraction Amount parameters of a V-RayMtl material), the resulting render will display the appropriate refraction information in the final image as well as in the possible three refraction elements that are used in compositing: VRayRefraction, VRayRawRefraction, and VRayRefractionFilter.
- Refraction Render Element (VRayRefraction) – This element is a key component in the main Beauty Pass. It displays the proper refraction according to the values set in the material. It is easy to adjust this element for brightness, coloration, etc. of the refractions in your scene without the need to re-render. This element is most often used by itself, but can be further controlled by the other two refraction elements listed below.
- Raw Refraction (VRayRawRefraction) – This element is a key component of the Refraction Render Element and contains the pure surface refraction before it is multiplied by the refraction filter color. This element must be multiplied by the Refraction Filter for a proper refraction in the final composite as intended for the material.
- Refraction Filter (VRayRefractionFilter) – This element is a key component of the Refraction Render Element. The refraction filter properly attenuates the amount of refraction a surface is designed to have by virtue of the Refraction Amount parameter set for its material. The refraction filter must be multiplied by the raw refraction in the composite.
Basically, the raw refraction element gives the full refraction of objects refracting in the scene, while the refraction filter sets how much of that refraction should come through in the composite. When these two elements are multiplied, the true level of refraction is given. Using these component parts of the refraction, you can better fine-tune the refraction in your final composite.
Render Element Examples
Refraction Render Element
Raw Refraction Render Element
Refraction Filter Render Element
Refracted render channels often override information seen through glossy materials like windows.
Refraction render elements can be changed without re-rendering in a compositing program.
- These render elements can be both added and subtracted from existing Refractions within the scene.
When a Matte Render Element is used, certain objects or materials within the scene can be isolated at a composite level and the refractivity of these items changed as needed without rerendering.