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72 Chapter 17: Rendering
The radiosity mesh is the foundation for the
regathering process.
In the following illustrations, solutions were
processed w ith an Initial Quality of 0%. There
is a high variance between small surfaces when a
dense mesh is used. Regathering gives acceptable
results regardless of mesh density. But more subtle
details appear with a denser mesh; for example, a t
thebaseofthesculpture.
No mesh
Left: Model subdivision
Middle: Viewport result
Right: Result of regathering
Coarse mesh
Left: Model subdivision
Middle: Viewport result
Right: Result of regathering
Fine mesh
Left: Model subdivision
Middle: Viewport result
Right: Result of regathering
R ay s per S ample—The number of rays 3ds Max
casts for each sample. 3ds Max casts these rays
randomly in all directions to calculate (“regather”)
the indirect illumination from the scene. The more
rayspersample,themoreprecisethesamplewill
be. Fewer rays per sample produce more variance,
creating a more gr ainy effect. Processing speed and
precision are affected by this value. Default=64.
Filter R adius (pixels)—Averages each sample with
its neighbors in order to reduce the noisy effect.
Default=2.5 pixels.
Note: Pixelradiusvariesaccordingtotheoutput
resolution. For example, a 2.5 radius is OK for
NTSC resolution, but it might be very large for
smaller images, or too precise for very large
images.
Pixel radius of 2
Left: 10 rays per sample
Middle: 50 rays per sample
Right: 150 rays per sample
Pixel radius of 5
Left: 10 rays per sample
Middle: 50 rays per sample
Right: 150 rays per sample