VRay Dome Light
The VRay Dome Light is a V-Ray specific light source plugin that can be used to create physically accurate area lights.
Enable - turns the VRay Dome Light on and off
Color - specifies the color of the light when the Mode parameter is set to Color. When using photometric units, this color is normalized so that only the color hue is used, whereas the light intensity is determined by the light Intensity.
Intensity - this value determines the light intensity.
Units - allows choosing the light units. Using correct units is essential when you work with the VRayPhysicalCamera. The light will automatically take the scene units scale into consideration to produce the correct result for the scale you are working with. The possible values are:
Default (scalar) - the color and multiplier directly determine the visible color of the light without any conversion. The light surface will appear with the given color in the final image when seen directly by the camera (assuming there is no color mapping involved).
Luminous power (lm) - total emitted visible light power measured in lumens. When this setting is used, the intensity of the light will not depend on its size. A typical 100W incandescent light bulb emits about 1500 lumens of light.
Luminance (lm/m^2/sr) - visible light surface power measured in lumens per square meter per steradian. When this setting is used, the intensity of the light depends on its size.
Radiant power (W) - total emitted visible light power measured in watts. When using this setting, the intensity of the light does not depend on its size. Keep in mind that this is not the same as the electric power consumed by a light bulb for example. A typical 100W light bulb only emits between 2 and 3 watts as visible light.
Radiance (W/m²/sr) - visible light surface power measured in watts per square meter per steradian. When this setting is used, the intensity of the light depends on its size.
Use Dome Texture - this tells the light to use a texture for the light surface. If there are surfaces which are close to a texture-mapped light, it is best to have GI enabled. This allows V-Ray to use combined direct and indirect sampling for the light, reducing the noise for surfaces close to the light.
Dome Texture - specifies the texture to use. The texture intensity is also affected by the Intensity of the light.
Texture Resolution - specifies the resolution at which the texture is resampled for importance sampling.
Target radius - for the Dome light, defines a sphere around the light icon where photons are being shot when photon-mapped caustics or the global photon map are used.
Emit radius - for the Dome light, defines a sphere around the light icon from which photons are being shot towards the target radius area.
Spherical - when on, this option causes the dome light to cover the entire sphere around the scene. When off (the default), the light covers a hemisphere only.
Adaptive - controls the amount to which light sampling is tuned to the texture brightness. If 0.0, no adaptation based on texture intensity is performed. When set to 1.0 (the default), the maximum amount of adaptation is used. Changing this parameter may be required if there are very bright portions of the map, which are however obscured for the particular scene. This will prevent the light from concentrating a lot of samples in this area and shooting too few samples in other parts of the texture. This parameter is ignored when the light type is Mesh as in that case sampling is not dictated by texture brightness.
Ray Distance - allows you to specify the maximum distance to which shadow rays are going to be traced.
Ray Distance Mode - allows you to specify the mode to which V-Ray will use to calculate the Ray Distance.
From GI Settings - the Ray Distance value is determined by the Ray Dist parameter in the GI settings.
Explicit - the Ray Distance value is determined by the Ray Distance parameter.
Invisible - this setting controls whether the shape of the VRayLight source is visible in the render result. When this option is turned off the source is rendered in the current light color. Otherwise it is not visible in the scene. Note that this option only affects the visibility of the light when seen directly by the camera or through refractions. The visibility of the light with respect to reflections is controlled by the Affect specular option.
Store in Irrad. map - when this option is on and GI calculation is set to Irradiance map V-Ray will calculate the effects of the VRayLight 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.
Affect diffuse - this determines whether the light is affecting the diffuse properties of the materials.
Affect specular - this determines whether the light is affecting the specular of the materials.
- this determines whether the light will appear in reflections of
Subdivs - this value controls the number of samples V-Ray takes to compute lighting. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time. Note that the actual number of samples also depends on the DMC Sampler settings.
Photon Subdivs- this value is used by V-Ray when calculating the Global Photon Map. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time.
Caustic Subdivs- this value is used by V-Ray when calculating Caustics. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time.
Cutoff Threshold- this parameter 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 you specify 0.0, the light will be calculated for all surfaces.
Shadows - when on (the default), the light casts shadows. Turn this option off to disable shadow casting for the light.
Shadow Bias - bias moves the shadow toward or away from the shadow-casting object (or objects). If the Bias value is too low, shadows can "leak" through places they shouldn't, produce moire patterns or making out-of-place dark areas on meshes. If Bias is too high, shadows can "detach" from an object. If the Bias value is too extreme in either direction, shadows might not be rendered at all.
Shadow Color - this parameter specifies a shadow color for this light. Note that any other color than black is not physically correct.
Shadow Texture - this parameter specifies a texture file to use as a shadow.