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

V-Ray for SketchUp
64

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Image on the left is showing -3 to 0. Image on the right is showing -3 to 1. Although the one on the 
right has the better final result, but the difference is very little.
Image on the left is showing last prepass of -3 and -2. Image on the right is the final result.
Image on the left is showing the last prepass of -4 and -3. Image on the right is the final result.
V-Ray for SketchUp
65

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When Min
Rate
and
Max
Rate
are
too
low
, “
leaking light
” 
happens
even
if
the
objects
are
joined
together
. 
See
image
on
the
left
for
example
.
This
is
due
to
lack
of
Samples
when
calculating
the
Prepass
. 
Of
course
, 
this
only
happens
when
using
Irradiance
Map
rendering engine.
Image on the left is rendered with Min Rate and Max Rate of -4 and -3. You
can
see
light comes through the 
corner
clearly
. The image on the right i
ncreased the
value
to
-3 
and
0 
and
you
can see
a
big
improvement
.
When working with complex images it may be necessary to do more than just adjust the Min and Max Rate.
Subdivisions are the next means of quality control with Irradiance Map. Higher subdivisions will yeild 
better quality. With Higher subdivisions it may also be necessary to add more samples. In the examples 
below both images have been calculated with the same Min/Max Rate, yet the Subdivisions have been 
increased from 50 to 100, and the samples have been increased from 20 to 40. You can see in the 
arangement of the irrandiance points (the little white dots) that the second image is much smoother.