Lighting an Interior Nighttime Scene Using IES Lights - Photographic Rendering with V-Ray for SketchUp - page 94

As soon as we try to dial in a nighttime setting, however, we should instantly
see the problem that we naturally run into. The Time slider control limits the
range of time that we can work with, only allowing us to set the slider some-
where between sunrise and sunset.
Note
The exact times available to us for sunrise and sunset will of course vary
according to the month of the year and the time zone settings that we are
working with.
Now it may occur to us to bypass the slider altogether and try typing more
suitable values into the numeric fields themselves, maybe setting the time of
day to, for example, 23:00 hours. If we do that, be prepared to see some very
strange color effects going on in any test renders that we may make. More
than likely, we will end up with odd results that make it look as though we
have entered into some kind of alternate dimension.
One way that we could get something along the lines of what we are looking
for would be to make some changes to the V-Ray Sky map itself. To take a
look at just what we could do there, let's continue with the following steps:
2. In the Environment rollout of the V-Ray option editor, Click on the GI (sky-
light) map button.
3. In the V-Ray texture editor that pops up, disable the sun plugin by clicking
on the dropdown in the Default Sky Options section and selecting the None
option.
4. We can then access the Sky Model dropdown in the same section and set
that to use CIE Overcast .
5. Set the Horizon Illum value all the way down to 125 .
6. After that, click on OK to exit texture editor .
7. We also need to click on the Map button for the Reflection/refraction (back-
ground) option and this time in the Sun controls section, set the Sky Model
to CIE Overcast .
8. With the Horizon Illum value set at 2 , finally click on Ok to exit.