This page provide information on the V-Ray Light Settings that can be added to any light source.

 

Page Contents

 

Overview


The V-Ray Light Settings are additional V-Ray related settings that can be added to any light source in the scene. By default V-Ray automatically adds these settings when a new light source is created. This behavior can be changed from the V-Ray Preferences. Some of the settings are common for all light sources and some are unique to specific light sources. Below is a list of all settings.

 


 

UI Path:

||Select lights|| > V-Ray menu > Add or Remove V-Ray package > Add V-Ray Light Settings to selected lights

 

 

 ||Select Lights|| > V-Ray Toolbar > Add or Remove V-Ray packages > Add V-Ray Light Settings to selected lights


 

Parameters


Photon emission


 

 

 

Photon subdivs – Controls the number of diffuse photons traced for the light. Larger values mean a more precise photon map, but will take more memory and time to render.

Diffuse multiplier – A multiplier for the diffuse photons generated by this light.

Caustic subdivs – Controls the amount of photons that V-Ray will trace to estimate caustics. Large numbers slow down the calculation of the caustics photon map and may take more memory.

Caustics multiplier – A multiplier for the caustics generated by this light. Note that this multiplier is cumulative - it does not override the multiplier in the Caustics render rollout section.

 

Options


 

 

 

Shadow bias – Moves the shadow toward or away from the shadow-casting object(s). If the value is too low, shadows can "leak" through places they shouldn't, producing moire patterns or making out-of-place dark areas on meshes. If set too high, shadows can "detach" from an object. If the the value is too extreme in either direction, shadows might not be rendered at all.

Cut-off threshold – Specifies a threshold for the light intensity, below which the light will not be computed. This can be useful in scenes with many lights, where you want to limit the effect of the lights to some distance around them. Larger values cut away more from the light; lower values make the light range larger. If set to 0.0, the light will be calculated for all surfaces.

Affect diffuse – Determines whether the light is affecting the diffuse portion of the materials. The Affect Diffuse value in the Modo Light Material parameters acts as a multiplier to control the light's contribution to the diffuse portion of the materials.

Affect specular – Determines whether the light is affecting the specular portion of the materials. The Affect Specular value in the Modo Light Material parameters acts as a multiplier to control the light's contribution to specular reflections.

Bumped normal check – When enabled, the bumped normal will be used to check if the light direction is below the surface for surfaces that are bump-mapped.

Store with irradiance map – When enabled, and Irradiance map is selected as the Global Illumination engine, V-Ray will calculate the effects of the light and store them in the irradiance map. The result is that the irradiance map is computed more slowly but the rendering takes less time. You can also save the irradiance map and reuse it later.

Use V-Ray subdivs – Controls the quality (noise) of soft shadows with the V-Ray Subdivs parameter instead of the Modo samples.

Subdivs – Determines the quality of soft shadows. Lower values render faster but may produce more noise, higher values produce a better result but may slow down the rendering. Note: The actual number of samples is the square of the value specified. (Modo samples = V-Ray Subdivs*V-Ray Subdivs i.e. V-Ray Subdivs = 8 is the same as Modo samples = 64). In order to use this value, the Use local subdivs option must be enabled in the DMC Sampler settings.

 

Light type specific parameters


Area Light


 

 


Double Sided – When enabled, light will be emitted from both sides of the area light.

Use texture – Sets the light to use a texture for the light surface. The texture is placed in the Shader tree with Light Color effect for the Light Material.

Texture resolution – Specifies the resolution at which the texture is sampled when the Adaptive texture sampling option is enabled.

Adaptive texture sampling – When enabled, V-Ray will use importance sampling on the texture in order to produce better shadows.

Directional – Narrows the spread of the area light, concentrating the light in a particular direction. At the default value of 0.0, the light from the Area Light is spread out equally in all directions.

Light mesh – Allows a mesh item to be connected which will specify the shape of the light; the mesh item's transformation is used, but visibility and textures are still controlled from the area light. The mesh is automatically excluded from the scene.

 

Dome Light  


 

 

 

Use texture – Sets the Dome light to use a texture as a light source. The texture is placed in the Shader tree with Light Color effect for the Light Material.

Texture resolution – Specifies the resolution at which the texture is sampled when the Adaptive texture sampling option is enabled.

Adaptive texture sampling – When enabled, V-Ray will use importance sampling on the texture in order to produce better shadows.

Dome Spherical – When enabled, the dome light covers the entire scene with a sphere. When disabled (the default), the light covers a hemisphere only.

Photon target radius – Defines a sphere around the center of the dome light toward which photons are fired. This radius should encompass all glass and metal surfaces that you want to create caustics.

Photon emit radius – Defines a sphere around the center of the dome light from which photons are fired. This radius should encompass all geometry in the scene.

 

Point Light


 

 

 

Make spherical – When enabled, turns the Modo Point Light into a V-Ray Spherical Light.

Sphere segments – Controls the quality of the light object when it is visible either directly or in reflections. A larger number makes the light sphere smoother.

 

Portal Light


 

 

 

Light mesh – Allows a mesh to be used as a light source.

 

Photometric Light  


 

 

IES light shape – Determines the shape of the light to use when calculating soft shadows.

Use Modo's Width / Height – Uses the Width and Height from the Photometric Light tab to create a rectangular shape. This is the default value and matches the Modo renderer behavior.

From IES File – The shape specified in the IES file is used. This option might give you the best results, since the shape will match the IES light's profile.

Point – Disables soft shadows for the light.

Rectangular/Circular/Sphere/etc. – Specifies a particular shape to use (listed below). Based on the selected option, additional fields will appear for setting the dimensions of the shape. Selecting a shape to use for the IES light will affect soft shadows, whereas IES lights with no shape defined will calculate shadows as rectangle lights, according to Modo's width and height parameters.

  • Point
  • Rectangular
  • Circular
  • Sphere
  • Vertical Cylinder
  • Horizontal cylinder oriented along lum. length
 
  • Horizontal cylinder oriented along lum. width
  • Ellipse oriented along lum. length
  • Ellipse oriented along lum. width
  • Ellipsoid along lum. length
  • Ellipsoid along lum. width
  • Elliptic cylinder
 
  • Hor. elliptic cylinder along lum. length
  • Hor. elliptic cylinder along lum. width
  • Vertical Circle
  • Vertical Ellipse
  • Cuboid

Motion blur samples


 

 

 

Override motion blur samples – When enabled, overrides the default number of samples that will be used to sample the current light for motion blur.

Motion blur samples – When the Override motion blur samples option is enabled, this is the value of samples for the motion blur of the current light.