2012

frequency specified for each light. The default value=1 for new presets. Values
are 0, 1/8, 1/4, 1/2, 1, 2. Draft: 0; Low:1/4; Med:1/2; High:1; Presentation:1.
Ray Tracing
Enable Specifies if ray tracing should be performed when shading.
Max Depth Limits the combination of reflection and refraction. Tracing of a
ray stops when the total number of reflections and refractions reaches the
maximum depth. For example, if Max Depth equals 3 and the two trace depths
each equal the default value of 2, a ray can be reflected twice and refracted
once, or vice versa, but it cannot be reflected and refracted four times.
Max Reflections Sets the number of times a ray can be reflected. At 0, no
reflection occurs. At 1, the ray can be reflected once only. At 2, the ray can
be reflected twice, and so on.
Max Refractions Sets the number of times a ray can be refracted. At 0, no
refraction occurs. At 1, the ray can be refracted once only. At 2, the ray can
be refracted twice, and so on.
Global Illumination
Enable Specifies if global illumination should be calculated for the scene.
Photons/Samples Sets how many photons are used to compute the intensity
of the global illumination. Increasing this value makes global illumination
less noisy but also more blurry. Decreasing this value makes global illumination
more noisy but less blurry. The larger the Samples value, the greater the
rendering time.
Use Radius Determines the size of photons. When on, the spinner value sets
the size of photons. When off, each photon is calculated to be 1/10 of the
radius of the full scene.
Radius Specifies the area within which photons will be used when illuminance
is computed.
Max Depth Limits the combination of reflection and refraction. Reflection
and refraction of a photon stop when the total number of both equals the
Max Depth setting. For example, if Max Depth equals 3 and the trace depths
each equal 2, a photon can be reflected twice and refracted once, or vice versa,
but it can’t be reflected and refracted four times.
Max Reflections Sets the number of times a photon can be reflected. At 0,
no reflection occurs. At 1, the photon can be reflected once only. At 2, the
photon can be reflected twice, and so on.
1650 | Chapter 18 R Commands