Hello and welcome to another V-Ray feature short demonstration.
In this video we will go over the V-Ray sun and sky system, the different sky models, and
the parameters that allow for fine tuning the sun and sky.
The V-Ray sun and sky system is meant to reproduce the real-life Sun and Sky environment of our planet.
the system itself consists of a direction of light source - to serve as the Sun,
and a procedurally generated High dynamic range texture to serve as the sky in our scene.
Both of those components are dynamic in a sense that they change depending
on the position of the sun , just like in real life.
Let's take a closer look at the sun light. Its intensity and light color depend on
the angle it makes with the horizon.
If the sun is perpendicular to the ground, at mid-day for instance, it will
have maximum intensity and it will shine with bright yellow color. But if the sun is closer
to sunrise or sunset position then its intensity would be much milder
and the light color would defer as well.
The intensity of the sun could be manipulated further by using the
intensity multiplier parameter.
Another parameter we can tweak is the size multiplier. By increasing the size, we
will make the visible sun bigger but that won't affect the light intensity at all.
Instead, it would only affect the softness of the shadows it casts.
Let's examine the V-Ray Sky component next.
As mentioned earlier, the sky isn't simply a background image. It's a procedurally
generated HDR texture that changes dynamically depending on the position of
the sun. Its purpose is to complement the V-Ray Sun light by generating an
environment with matching intensity and color. When creating a V-Ray Sun,
you will be prompted if you would like a V-Ray Sky texture to be added
automatically for you.
By default, the sky’s parameters are linked to the V-Ray Sun light, but they
can be overridden for achieving different looks.
If we have global illumination enabled in our scene, the V-Ray sky would affect its
intensity and color.
We could fine tune our sky appearance by tweaking the turbidity parameter.
It determines the amount of dust in the air.
Smaller values would result in less dust particles, therefore - a blue clear sky.
Higher values would shift the sky color towards yellow and orange as you would get in a
polluted urban environment for example. By changing the ozone parameter we can
affect the color of the light emitted by the sun.
There are multiple ways for the sky HDR texture to be generated. Each one
is based on a different sky model.
There are four sky models to chose from in the V-Ray Sun & Sky system. Each one
would result in slightly different outcome. In the Preetham model, the
intensity of the sun light and the brightness of the sky texture are linked
together. On another hand, the CIE model has those controls separated and includes
modes for a clear or an overcast sky.
As of version 3.3 of V-Ray there is a new sky model, called Hosek, which improves on
the previous ones.
Let's split up the screen and load each sky model playing the same sunrise-to
sunset animation.
This way we could clearly see the difference in each of them.
Additionally, in service pack 3 of V-Ray for 3ds Max, a new option called ground albedo
has been included.
It controls the general diffuse color of the ground.
Let’s load up a more complex scene so we can see the new Hosek sky model in
action. As of version 3.3 of V-Ray, there is a new, fast to render, environment fog type
of effect called “Aerial Perspective”. When used in conjunction with the sun and sky
system we could achieve more natural results.
In this short video tutorial, we have covered the V-Ray sun and sky system together
with all of the different sky models available and the essential parameters for fine
control such as turbidity, ozone, size and intensity multiplier.
I hope you have found this video useful and helpful. Make sure you check out more
V-Ray featured videos. Thanks for watching.