Graphics Programs Reference
In-Depth Information
Tip
The higher the ISO number we use in a render, the more sensitive V-Ray be-
comes to light, thereby producing a brighter final image. Unlike the ISO setting on
a digital camera, we can increase this value as much as we like in V-Ray without
the fear of introducing artifacts or noise into our rendered images.
Global illumination controls
The next aspect of our lighting setup that needs a little attention is the quality of the
indirect illumination solution. At this moment, we can see quite a bit of dark splotch-
ing on our nice clean geometry. This often happens when we work with scenes that
present a little bit of a challenge to the indirect illumination engines, which, of course,
interiors nearly always do. Couple this with the reasonably low-quality default set-
tings that V-Ray sets up, and we get splotches or noise patches in our render.
To clean this up a little, let's perform the following steps:
1. Jump into the
Irradiance map
rollout in the
option editor
, and in the
Basic
Parameters
section, set the minimum and maximum rate values to
-2
and
-1
respectively.
2. We can also increase the
HSph. subdivs
value to
125
and the
Interp.
samples
value to
35
.
3. Next, we can jump into the
Light cache
rollout and increase the
Subdivs
(or
subdivisions) value to
1200
.
If we take another render by hitting the button on the toolbar, we should see a
marked improvement in the level of splotchiness present in the image; not that every
trace of it will be gone, mind you. When working with interior scenes, creating com-
pletely noise-free
Global Illumination
(
GI
) renders can prove to be quite costly in
terms of the time it takes to render the final image.
What we often have to aim for then is a situation that would generally be considered
free enough of noise to be called an acceptable final solution. One reason why we
can often get away with this is the fact that once materials get applied to the geo-
metry, any slight levels of splotchiness still found in the scene tend to oftentimes just
blend into the materials themselves.
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