Graphics Programs Reference
In-Depth Information
Not that using the glossiness controls themselves come without penalty. When we
enter a value of less than 1 in any of these options, the simulation of light scattering
that we enable will require more in the way of sample rays in order to produce an
acceptable final result. And extra samples in a ray trace renderer of course, always
translate into longer render times. If we decide not to add the extra samples, then we
will find that we get a lot of noise showing up in the blurry reflections we are creating.
Perhaps the best way to demonstrate the difference this can make to the quality of
our finished material would be to take our highly reflective barrier chrome material,
apply it to one of our sculpts, and then lower its glossiness value to 0.75 to introduce
a fairly high level of scattering to the reflections. The three comparison renders we
can see here demonstrate the difference between the default sample or subdiv value
setting of 8 as compared to the subsequent doubling up of 16 and then 32 glossiness
subdivs. Note also the difference in render times on a pretty low-powered quad-core
Intel i5 laptop.
Note
The reason for the big increase in render times that we will experience as we
double each of these numbers also comes in part from the fact that the subdivs
values found anywhere in the V-Ray UI does not report the actual sample or ray
numbers being used, instead giving us the square of them.
With a subdiv value of 8 set in the Glossiness controls of our material for in-
stance, we are in fact making use of 64 samples or rays per pixel (8 multiplied by
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