Rendering and Illumination - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 320

The Ray Tracing panel allows us to control the maximum number of reflections and
refractions for rays used in render calculation, with Max depth being the sum of re-
flections and refractions.
The Indirect Illumination panel contains the following areas:
• Global Illumination : With the lamp turned on, indirect lighting is con-
sidered, that is, light reflects on objects. With this turned off, areas without
direct lighting will render as black. Photons/sample specifies how many
photons per sample are considered. Use radius , if on, specifies a radius
for samples. The remaining parameters define the photons' number of re-
flections and refractions; larger values will cause brighter indirect illumin-
ation, but will need more time for rendering.
• Final Gather : This is another mechanism for processing indirect lighting,
where rays are shot from the user view (or camera). It is normally faster
than global illumination. We control the number of rays and also if a
sample radius will be used, and its maximum and minimum values.
• Light Properties : We can specify the number of photons per light and an
energy multiplier.
The Diagnostic panel includes some advanced tools for analyzing the render mech-
anism.
Finally, the Processing panel specifies the size, method, and memory limit for the
small squares (buckets) used in render calculations.
Note
For most users, it is enough to apply the Render Context parameters and
choose a preset render quality. While improving the scene, the Medium preset
is okay. For final renders, the High or Presentation preset should be used, with
the latter advised when the materials' textures don't look good enough.
The RENDERPRESETS command
The RENDERPRESETS command (alias RP ) allows us to define preset render qualit-
ies. Besides the five presets available, we may define any number of new presets.