U g I n f o r d e s I g n e r s

V-Ray for SketchUp
79

---

Changin the Sun’s Appearance with Ozone
The other useful parameter in adjusting the sun is Ozone. Ozone changes the color of the sun 
itself from a slightly yellow tone to a slightly blue tone. This can be very useful for fine 
adjustments to the appearance of the sun.
Ozone= 0
Ozone= 0.5
Ozone= 1
Gamma Correction and the V-Ray Sun and Sky
Due to the physical nature of the sun and sky model it is intended to be rendered using a gamma 
corrected linear workflow. Gamma correction compensates for a monitor’s tendency to display 
mid-tones darker than they actually are. Most programs embed the correction for this into the 
image, but because of the nature of how V-Ray processes color information it does not correct for 
this. Ultimately the result is that the Vray Sky will appear too dark if it is not corrected for 
display on our monitors. Also if the image is not gamma corrected the influence of the sky will not 
be accurate either. Needless to say, gamma correction is very important, extremely so when using 
the V-Ray Sun and Sky. 
The image on the far left is 
has no gamma correction.
This causes the sky to be dark 
and its colors to be 
inaccurate. The closer image 
has been gamma corrected, 
which brightens the sky as 
well as having colors which 
accurately represent the 
sky’s influence.
Enabling Gamma Correction
In order to gamma correct images 
both the inputs (textures and colors)
and output need to be adjusted.
This is very quick and simple to do 
with V-Ray as well as not impeding 
on workflow. In Global Switches, 
there is a section in the bottom right 
corner containing the controls for 
gamma correction. To adjust the 
inputs check Correct RGB and 
Correct LDR Textures. To adjust the 
output change the Gamma value 
from 1 to 2.2