Autodesk 256B1-05A761-1301 - AutoCAD Revit Structure Suite 2010, Руководство пользователя

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For example, a smooth monochrome surface renders more quickly than a smooth patterned surface. A
large-scale pattern renders more quickly than a dense, intricate pattern. A detailed, perforated surface renders
more slowly than a simple surface.
The material render appearances that require the most time to render are (from slower to slowest): metallic
paint, flecked metal, hammered metal, water, frosted glass, and perforated metal. Slower render times for
these materials are proportional to how much of the scene they cover.
At the draft to medium quality settings, complicated materials may show many artifacts (small inaccuracies
or imperfections in the rendered image). Imperfectly reflective materials (such as wood floors and metal
mullions) appear speckled. These issues can be improved by adjusting the Blurred Reflection Precision value.
(See
Render Quality Settings on page 1225.)
To improve the appearance of patterned surfaces and silhouettes without significantly increasing render
time, adjust the Image Precision (Antialiasing) value. (See
Render Quality Settings on page 1225.) To produce
images with little lighting depth but crisp geometry, use the draft quality setting with a high value for Image
Precision (Antialiasing), such as 6.
How Reflection Types Affect Render Performance
The render appearance of a material specifies its reflectivity. Revit Architecture can render matte reflections
quickly. However, any material characteristic that causes visual distortions (such as blurred reflections or
transparencies) requires more work to render, and so requires more render time.
Shiny and mirrored reflections are slightly more difficult to render than matte reflections. A fritted surface
is more difficult to render than a smooth, glossy surface. Water is more difficult to render than glass. Metal
with a patina or a hammered surface is more difficult to render than polished metal.
Blurred reflections are the most difficult to calculate. However, you can control the quality of blurred
reflections to reduce the impact on render performance. (Use the Reflections and Transparency options. See
Render Quality Settings on page 1225.)
How Refractions and Reflections Affect Render Performance
Refractive materials, like glass, usually involve reflections as well. As a result, these materials are more
expensive (in time and resources) to render than others. Also, the average pane of glass has 2 layers or sides,
requiring multiple layers of refraction. When rendering an image, all of the layers must be calculated so you
can see through the glass. For example, you need at least 6 refractions to see through 3 panes of solid glass.
When rendering an image, you can specify the number of bounces off reflective surfaces (Maximum Number
of Reflections), and the number of panes of glass for refractions (Maximum Number of Refractions). Higher
settings generally result in longer render times. Blurry refractions increase render time further. (In the Render
Quality Settings dialog, use the Reflections and Transparency options. See
Render Quality Settings on page
1225.)
Render Performance and Image Size/Quality
The image size or resolution of a rendered image has a predictable effect on render time. The Image Precision
(Antialiasing) setting affects render time in a similar way. (See
Render Quality Settings on page 1225.) Higher
values for image size, resolution, or precision require more time to generate the rendered image.
Effect of Increasing Image Resolution
If you double the image resolution (for example, from 75 dpi to 150 dpi) without changing other settings,
render time can increase by 2 to 4 times. (Depending on the complexity of the image being rendered, the
1236 | Chapter 19 Rendering