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Table of Contents

This page provides information on the Render overrides rollout in the Render Settings.

 

Overview

The Rendering Overrides options can be used to override certain aspects of the way the scene is rendered.

 

UI Path: ||Render Settings window|| > Overrides tab > Rendering rollout

 

 

 

Parameters

Don't render final image – Image rendering is bypassed, allowing for other calculations, like texture baking or GI caching.

Secondary rays bias – A small positive offset applied to all secondary rays. This setting is useful when the scene contains overlapping faces, which can cause black splotches to appear in the rendering. For more information, see the Secondary Rays Bias example below. 

When overlapping faces are present in a scene, in order for GI to calculate correctly it is often necessary to assign a 2-sided material to the overlapping objects in addition to enabling the Secondary rays bias option.

Clamp max ray intensity – Uses the Max ray intensity value to suppress the contribution of very bright rays, which can typically cause excessive noise (fireflies) in the rendered image. The Max ray intensity value is applied to all secondary (GI/reflection/refraction) rays as opposed to the final image samples, allowing fireflies to be effectively suppressed without losing too much HDR information in the final image.

Max ray intensity – The maximum ray intensity when Clamp max ray intensity is enabled. 

The effect of using Max ray intensity + Clamp max ray intensity is similar to the effect of using Subpixel mapping + Clamp output options on the Color mapping rollout. Similar to the Subpixel mapping option, Max ray intensity introduces bias in the rendered image, and it might turn out to be darker than the actual correct result.

GI texture filtering multiplier – Controls the filtering of all the textures in the scene when Global Illumination is calculated. Greater values make textures blurrier while smaller values make them sharper. When using V-Ray GPU renderer, this option is not available.

Up Vector – Specifies the up-vector for the scene. This setting can be useful when importing data from other applications (such as 3ds Max) where the up-vector is not Y as in Maya.

Cache geometry plugins between renders – When enabled, V-Ray keeps all loaded geometry in memory after the rendering is complete, allowing the next render to start faster in cases when the geometry is unchanged.

Clear geometry cache – Manually clears any geometry cache left between renders. Otherwise, the geometry cache will be automatically cleared on the next render if Cache geometry plugins between renders is enabled.

Cache bitmaps between renders – When enabled, V-Ray keeps all loaded textures in memory after the rendering is complete. This means the next render can start faster as textures don't need to be reloaded.

Clear bitmap cache – Manually clears any bitmap cache left between renders. Otherwise, the textures cache will be automatically cleared on the next render if Cache bitmaps between renders is enabled.

Use Maya shader for V-Ray proxies – For scenes created before V-Ray 3.1. Determines whether a proxy is going to be rendered with materials connected to the original mesh, or materials connected to the proxy instance.

Clear V-Ray proxies preview cache – Manually clears proxies preview cache. VRayProxy nodes allow caching of the geometry for faster preview; clearing the cache saves memory, and also makes it possible to reload the proxy if it has been changed.

Consistent lightning elements – When enabled, this option provides more accurate, artifact-free lighting render elements not dependent on light sampling. It also provides better support for Adaptive dome light. Please note, that this option is applicable to raw lighting render elements only when the corresponding normal and filter render elements are available (e.g., VRayRawGlobalIllumination = VRayGlobalIllumination / DiffuseFilter).

 

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 Rendering rollout under the Overrides tab in the Render Settings 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.

 



 

Example: Secondary Rays Bias


This example shows the effect of the Secondary rays bias parameter. The scene below has a box object with a height of 0.0, which makes the two sides of the box to occupy exactly the same region in space. Due to the overlapping faces, V-Ray cannot resolve intersections of rays with these surfaces.


 

The first image shows what happens when the scene is rendered with the default settings. Splotches appear in the GI solution, caused by the fact that rays randomly intersect one or the other surface:



In the second image below, the Secondary rays bias is set to 0.001, which offsets the start of each ray a little bit along its direction. In effect, this makes V-Ray skip the problematic surface overlaps and render the scene correctly:


 

Note that the Secondary rays bias setting affects light ray calculations in the rendering (such as GI and reflections), but it alone cannot correct for materials on overlapping faces. In order to correctly render the overlapping faces, the material assigned to the box has its 2-sided option checked. This is so that the object looks the same way regardless of whether the camera rays hit the top or the bottom of the box. If the material did not have this option checked, it would appear "noisy" even though the Secondary rays bias is greater than 0.0: