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50 Chapter 17: Rendering
Initial sampling uses a regular grid.
Adaptive undersampling concentrates on transition areas.
Tip: If you use adaptive undersampling, try
adjusting the Subdivision Contrast value to obtain
the best results. The effect of this control depends
on the value of Rays/Sample.
Adaptive Undersampling—When on, the Light
Tracer uses undersampling. When off, it samples
every pixel. Tur ning this off can increase the detail
of the final rendering, but at a cost of rendering
time. Default=on.
Initial Sample S pacing—The grid spacing for the
initial samples of the image. This is measured in
pixels. Default=16x16.
Initial sample spacing values
Subdivision Contrast—The contrast threshold
that determines when a region should be further
subdivided. Increasingthisvaluecausesless
subdividing to occur. Too low a value can cause
unnecessary subdividing. Default=5.0.
Decreas ing the subdivision contrast threshold can reduce noise
in soft shadows and bounced lighting.
Subdivide Down To—The minimum spacing for a
subdivision. Increasing this value can improve
render time at a cost of accuracy. Default=1x1.
Depending on the scene geometry, grids larger
than 1x1 mig ht still be subdivided below this
specified threshold.
Show Samples—When on, sample locations render
as red dots. This shows where the most sampling
has taken place, which can help you cho ose the
optimal settings for undersampling. Default=off.