sun, sky, VRaySun, VRaySky, environment, daylight, sunlight, exterior
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
and references section.
The VRaySun is
located in the (Create - Lights - VRay) panel. You can also specify the
VRaySun as the sun type inside a 3ds Max
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.
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
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
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.
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
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
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 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. For further info,
please see the Examples section.
Photon emit radius - determines the radius
of the area, in where photons would be shot. This area is represented by the
green cylinder around the Sun's ray vector. This parameter has effect when
photons are used in the GI solutions or caustics.
Exclude - this button allows you to
exclude objects from illumination/shadow casting for the sun light.
VRaySky texture map is typically used as an
environment map, either in the 3dsmax Environment
dialog, or in one of the slots of the V-Ray
Environment rollout and behaves very much like a HDRI environment map.
The VRaySky changes its appearance based on the
position of the VRaySun.
Manual sun node - specifies how the
VRaySky detemines its parameters:
Off - the VRaySky
will automatically take its parameters from the first enabled
VRaySun in the scene. In this case, none of
the other parameters of VRaySky are
On - you can choose a different light
source. It is recommended that you choose only direct lights, as the
vector for the direction is taken into consideration when computing the
appearance of the sky. In that case the VRaySun
is no longer controlling the VRaySky and the
parameters in the texture map rollout determine the final look of the
Sun node - specifies which light source is
chosen if Specify sun node is
Sun turbidity - refer to
Sun ozone - refer to
Sun intensity multiplier - refer to
Sun size multiplier - refer to
Sun invisible - when this option is on,
the sun disk will not be visible on the sky texture.