VRaySun and VRaySky parameters
Links and references
Search keywords: sun, sky, VRaySun, VRaySky, environment, daylight, sunlight, exterior lighting
The VRaySun and VRaySky are special features which are provided by the V-Ray renderer. Developed to work together, the VRaySun and VRaySky reproduce the real-life Sun and Sky environment of the Earth. Both are coded so that they change their appearance depending on the direction of the VRaySun.
The V-Ray Sun and Sky are based largely on the SIGGRAPH'99 paper "A Practical Analytic Model for Daylight" by A. J. Preetham, Peter Shirley, Brian Smits. For a more complete list of references, please see the Links and references section.
To create a VRaySun object go to VRay Sky rollout in the VRay Tab of the Render Settings dialogue and press the button.
Enabled - turns on and off the sun light.
Invisible - when on, this option makes the sun invisible, both to the camera and to reflections. This is useful to prevent bright speckles on glossy surfaces where a ray with low probability hits the extremely bright sun disk.
Intensity multiplier - this is an intensity multiplier for the VRaySun. Since the sun is very bright by default, you can use this parameter to reduce its effect. See the Notes and Examples sections for more information.
Turbidity - this parameter determines the amount of dust in the air and affects the color of the sun and sky. Smaller values produce a clear and blue sky and sun as you get in the country, while larger values make them yellow and orange as, for example, in a big city. For further info, please see the Examples section.
Ozone - this parameter affects the color of the sun light. Available in the range between 0.0 and 1.0. Smaller values make the sunlight more yellow, larger values make it blue. For further info, please see the Examples section.
Size multiplier - this parameter controls the visible size of the sun. This affects the appearance of the sun disc as seen by the camera and reflections, as well as the blurriness of the sun shadows. For further information, please see the Examples section.
Sky model - Allows you to specify the procedural model that will be used to generate the VRaySky texture.
Preetham et al. - when this mode is selected the VRaySky procedural texture will be generated based on the Preetham et al. method.
CIE Clear - when this mode is selected the VRaySky procedural texture will be generated based on the CIE method for clear sky.
CIE Overcast - when this mode is selected the VRaySky procedural texture will be generated based on the CIE method for cloudy sky
Indirect horiz. illum. - specifies the intensity (in lx) of the illumination on horizontal surfaces coming from the sky
Cast Shadows - when on the sun will produce shadows.
Cast Shadows from environment - when on the sun will produce shadows from volumetric effects.
Shadow subdivs - this controls the number of samples for the area shadow of the sun. More subdivs produce area shadows with better quality but render slower. For further info, please see the Examples section.
Shadow 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 make 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. For further info, please see the Examples section.
Photon radius - determines the radius of the area, in where photons will be shot. This area is represented by the cyllinder around the Sun's ray vector. This parameter has effect when photons are used in the GI solutions or caustics.
Photon emit distance - this parameter defines a radius arround the sun from where the photons will be shot.
Photons 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.
Caustics 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.
The VRaySky texture map is typically used as an environment map. It changes its appearance based on the position of the VRaySun.
Intensity multiplier - this parameter determines the intensity of the light coming from the VRaySky.
Sun - allows you to assign a VRaySun to the VRaySky object to use for the calculations of its appearance.
Here is a list of links and references about the V-Ray Sun and Sky implementation, as well as general information about the illumination of the Sun.