This page provides information on the Options tab of the V-Ray Renderer parameters.
Page Contents
Overview
The Options tab globally control some geometry, lighting, material, and texture aspects of the rendering. For example, these options can be used to disable all shadows in your scene, or to use probabilistic light sampling to speed up test renders.
UI Path: ||Parameters tab|| > Options tab (with the V-Ray Renderer node selected)
Parameters
Enable Displacement – Enables or disables V-Ray displacement mapping.
Render Hidden Geometry – Determines whether or not geometry that is sometimes (or always) invisible is exported to V-Ray.
Use Lights – Enables lights globally. Note: Disabling this will cause V-Ray to use the default lights. If you do not want any direct lighting in your scene, you must disable both this and the Default lights override parameter .
Use Default Lights – Enables the usage of the default lights when there are no light objects in the scene or when you have disabled lighting globally with the Use Lights parameter.
Use Hidden lights – Determines whether or not lights marked as hidden (i.e. not Visible) will be exported to V-Ray.
Shadows – Enables shadows globally.
Show Gi Only – When enabled, only GI from lights will be used.
Disable Self-illumination – Disables the rendering of self-illuminated objects (i.e. objects assigned a VRayLightMtl).
Don't Render Final Image – When enabled, V-Ray will only calculate the relevant global illumination maps (photon maps, light maps, irradiance maps) and the final image will not be rendered. This is a useful option if for calculating maps for a fly-through animation.
Reflection / Refraction – Enables (default) or disables the calculation of reflections and refractions in V-Ray maps and materials.
Use Global Max Depth – Enables global limiting of the reflection/refraction depth. When this is disabled, the depth is controlled locally by materials. When this option is enabled, all materials use the Max depth specified in this rollout.
Global Max Depth – Specifies the maximum depth when Use Global Max Depth is checked. To disable reflections/refractions altogether, set this value to 0.
Maps – E nables (default) or disables texture maps. This option is useful for troubleshooting renderings, for example for determining the extent to which texture maps are contributing to noise or other rendering artifacts.
Filter Maps – Enables (default) or disables texture map filtering. When enabled, the depth is controlled locally by the settings of the texture maps. When disabled, no filtering is performed.
Filter Maps For Glossy/gi Rays – Enables filtering for glossy and GI rays.
Max. Transparency Levels – The depth to which transparent objects will be traced.
Transparency Cutoff – Determines when tracing of transparent objects will be stopped. If the accumulated transparency of a ray is below this threshold, no further tracing will be performed.
Override Material – Overrides the scene materials when rendering. All objects will be rendered with the chosen material, if one is selected, or with their default wireframe materials if no material is specified.
Glossy effects – Enables (default) or disables the rendering of glossy effects.
Uninverted Normal Bump – When enabled, the normal bump in tangent space will not be inverted on flipped UVs.
Force Back Face Culling – Enables or disables (default) back face culling for camera and shadow rays. When this option is enabled, the surfaces of objects which are turned away from the camera (or the light source, when tracing shadows) will appear fully transparent. This enables a camera outside a closed object to see inside it.
Note: This option does not function when the Use Embree option is enabled in the Raycaster tab. To force back face culling, Use Embree should be disabled
Secondary Rays Bias – A small positive offset that will be applied to all secondary rays; this can be used if you have overlapping faces in the scene to avoid the black splotches that may appear. For more information, see The Secondary Rays Bias example below.
Low thread priority – When enabled, uses below-normal worker thread priority, giving more CPU time to other running tasks
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.
Abort Rendering On Missing Asset – When enabled, the scene will not render if an asset fails to load.
Transfer Missing Assets on Dr – When using distributed rendering, a llows render servers to automatically download missing rendering assets from the client machine, including textures, V-Ray proxy files, IES profiles, GI solution caches (irradiance maps, light caches), etc.
Use Cached Assets on Dr – When enabled and using distributed rendering, the render servers keeps the downloaded rendering assets between different DR sessions. If disabled, the render assets are automatically deleted once the render server disconnects from the client machine at the end of the rendering. When enabled, assets are kept in a folder on disk. By default, it is named vray_assets_cache located in the temporary folder for the user that runs the V-Ray DR spawner. The location of the assets cache can be modified with the environment variable VRAY_ASSETS_CACHE_PATH. Modified assets are generally detected and re-transferred to the render servers even though they may already exist in the render servers' caches.
Cache Limit Type – Allows you to specify under what conditions the assets cache is cleaned up. The possible values are:
None – Assets are never deleted from the render servers' cache
Age (Hours) – Assets are kept for the specified amount of time. At the end of the rendering, the render servers will delete assets that have been transferred before the specified time limit.
Size (GB) – When the size of the assets on a render server exceeds the specified amount, least recently used assets are automatically deleted at the end of each render until the folder size is less than the limit.
Cache Limit Value – The specific value of the limit for the asset cache. This is either hours or GB, depending on the value of Cache Limit Type.
Overwrite Local Cache Settings – Available when Transfer Missing Assets on Dr and Use Cached Assets on Dr is enabled. Enabling will make the render nodes ignore their local settings for how long they'll keep a transferred asset if any such settings have been placed. Instead, the nodes will use the settings from the host's Houdini render settings.
Clamp Max Ray Intensity – Uses the Max ray intensity value to s uppress 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.
Note: The effect of using Max Ray Intensity and Clamp Max Ray Intensity is similar to the effect of using Subpixel Mapping and Clamp Output options on the Color Mapping tab. 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.
Mtl Override – Specifies the material to use in the scene when the Override Material option is enabled.
Sss Enabled – Enables (default) or disables the rendering of sub-surface scattering effects.
Light Evaluation Mode – Determines how lights are sampled in scenes with many lights.
Full Lights Evaluation – V-Ray goes through each scene light and evaluates it at each shading point. In scenes with many lights and lots of GI bounces, this leads to a lot of shadow rays being traced and rendering can become extremely slow. When GPU rendering, this will introduce probabilistic light calculations but will not allow the Number of Lights parameter to be set. Older V-Ray scenes with the Probabilistic Lights parameter disabled, will default to using this option. For more information, see the Probabilistic Lights example below.
Uniform Probabilistic Lights – V-Ray randomly chooses the specified number of lights and evaluates only those. Lower values make the rendering faster, but potentially more noisy. Higher values cause more lights to be computed at each shading point, thus producing less noise, but increasing render times. This option makes it possible to render images that would otherwise take a very long time, at the expense of possibly introducing more noise into the rendering. When GPU rendering, this will introduce probabilistic light calculations. Previous V-Ray 3 scenes that had the Probabilistic Lights parameter enabled, will default to using this option. For more information, see the Probabilistic Lights example below.
Adaptive Lights – Uses information from the Light cache to determine which lights to sample. If a Light cache is not used, uniform sampling will be used. Depending on the scene, it can be faster than the Full Lights Evaluation and Uniform Probabilistic Lights mode.
Number of Lights – Number of lights from the scene that are evaluated by V-Ray when the Light evaluation parameter is to either Adaptive or Uniform Probabilistic. To achieve a positive effect from probabilistic light sampling, this value must be lower than the actual number of lights in the scene. Lower values make the rendering go faster, but the result is potentially more noisy. Higher values cause more lights to be computed at each hit point, thus producing less noise but increasing render times. For more information, see the Probabilistic Lights example below.
Enable Probabilistic Volumetrics – If enabled, the volumetrics will select a few samples along each ray based on the smoke density, and evaluate the volume lighting at those points. If disabled, the volumetrics will evaluate the lighting at each step of the raymarching algorithm. The probabilistic mode is particularly useful when using the progressive sampler in V-Ray, as well as when using complex lighting on the volume. This mode only applies to the Volumetric Grid (VRayVolumeGrid) currently.
Number of Direct Samples – The number of probabilistic samples to use when Enable Probabilistic volumetrics is enabled. For best rendering performance, use higher number of samples for transparent smoke, and lower number for dense smoke. With very high number of samples, the sampling will basically converge to a standard ray-marching.
Number of Gi Samples – The number of probabilistic samples to use for GI rays. The number of samples depends on whether the volumetric has emissive component. Brighter emission requires more samples, while pure smoke can work with fewer.
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 the top and bottom of the box occupy exactly the same region in space. Due to this, V-Ray cannot resolve unambiguously intersections of rays with these surfaces.
The first image shows what happens when you try to render the scene with the default settings. You can see the splotches 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 affects only things like GI, reflections, etc. In order to render the scene properly, the material assigned to the box has its 2-sided option checked. This is so that the object looks in 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:
Example: Probabilistic Lights
Below is an example rendering of a scene with 1089 sphere lights with the Cutoff threshold set to 0.0. Both images were rendered with the Progressive image sampler and ran for the same amount of time. When probabilistic lights are enabled, the image is much cleaner as V-Ray manages to compute more GI rays (which are the main source of noise in this scene).
Probabilistic lights is Off
Probabilistic lights is On (8 lights)