This page gives some basic details about the Beauty RGB_Color render element and how it may be re-assembled in a composite using its component elements.
The Beauty Render (RGB_Color) is V-Ray's pre-composited final render and is usually the primary export when rendering a scene. During rendering, it is created automatically as the RGB color render element in the V-Ray Frame Buffer. This render element is unique in that it is not added separately under the Render Elements tab.
This pass can be re-created manually in a composite by assembling the proper components together and fine-tuning the components. This process is commonly called Back to Beauty Compositing.
For specifics on how the Beauty pass is reconstructed, see Back to Beauty Compositing below.
Since V-Ray Next Update 1, some of the render elements are rendered differently than before. The Lighting render element now contains all direct diffuse illumination and the GI element contains all indirect diffuse illumination. Similarly, all direct reflections of lights now go to the Specular element and all indirect reflections go to the Reflection element.
Previously this behavior depended on the sampling of the lights and not just on the type of the contribution. Some of the direct contributions that should be in the Lighting and Specular elements were written to the GI and Reflection elements instead. In both cases they compose back to Beauty correctly but the different types of contributions are now split between the elements more consistently.
This change makes the elements more consistent but it's also needed for preventing artifacts in these elements with the adaptive dome light (and possibly in the future with other adaptive lights).
The raw elements are affected only when the corresponding normal and filter elements are available, otherwise they're rendered as before. This is because the raw elements have to be derived internally from the corresponding normal elements in order to work with the consistent elements (e.g. VRayRawGlobalIllumination = VRayGlobalIllumination / DiffuseFilter).
There's an option to enable or disable the new behavior in the Global Switches rollout under the V-Ray tab in the Render Setup window. The consistent elements are automatically enabled when the scene contains an adaptive dome light so they don't have artifacts. They are also enabled by default for new scenes. For V-Ray GPU they are always enabled without an option to disable them.
Back to Beauty Compositing
The following is the base formula for reconstructing the Beauty pass. Some Render Elements can be excluded if the scene does not utilize them. Click the image to see the full-size version and zoom in to view all the render elements involved.
VRayLighting + VRayGlobalIllumination + VRayReflection + VRayRefraction + VRaySpecular + VRaySSS2 + VRaySelfIlumination + VRayCaustics + VRayAtmosphere + VRayBackground = RGB_Color (Beauty)
Advanced Back to Beauty
Occasionally there may be a need for more specific editing to the final image. For this, there's a more detailed workflow than the normal back to beauty workflow. Click the image to see the full-size version and zoom in to view all the render elements involved.
(VRayDiffuseFilter x (VRayRawLighting + VRayRawGlobalIllumination)) + (VRayRawReflection x VRayReflectionFilter) + (VRayRawRefraction x VRayRefractionFilter) + VRaySpecular + VRaySSS2 + VRaySelfIllumination + VRayCaustics + VRayAtmosphere + VRayBackground = RGB_Color (Beauty)
- There are two options for how Motion blur and Depth of Field are handled in the back-to-beauty composite. If Depth of field and/or Motion blur are enabled in the V-Ray Physical Camera, these effects are already baked into all of the render elements. In this scenario using the filter render elements in the advanced back-to-beauty composite can offer finer control of some render elements. Alternatively, many compositing and photo editing packages can add the effects post-rendering using specific tools that utilize VRayVelocity for motion blur and VRayZDepth for depth of field, with some limitations.