2011

Glossary
Glossary of technical terms relating to Autodesk Navisworks Simulate 2011.
Display Terminology
average frame rate This shows the current measured frame rate, averaged over the last second.
average frame time This shows the time taken to render the last frame.
average triangle rate This shows the rate at which triangles are being rendered and is a measure of how well
your graphics card is working.
culling Culling is a process for determining items not to draw during the render of a scene. Autodesk Navisworks
does a level of prioritized culling with the
drop-out method of rendering interactive scenes, but you have a
certain level of control over other aspects of culling such as backface, near and far planes.
drop-out In order to maintain interactivity and guarantee a user-defined frame rate, Autodesk Navisworks only
renders what it can in the fraction of a second it has. The remainder is “dropped out”, or not rendered.
Autodesk Navisworks prioritizes what is rendered and what is dropped out based on size of the item's bounding
box, distance from viewer and size on screen, so only the less significant items in the scene are dropped out.
Once navigation has ceased, the scene continues rendering until all items are visible.
frame rate The frame rate is the number of frames per second (FPS) that are rendered in the main navigation
window. Autodesk Navisworks guarantees a user-defined frame rate in order to maintain interactivity.
Export Terminology
These are terms specific to Autodesk Navisworks that are used in relation to exporting.
codec Codec stands for “COmpression-DECompression” and is a program that compresses and decompresses
animations when creating and playing back AVI files. Codecs are installed independently of Autodesk Navisworks
and are available when installed on your Windows
™
system and the same codec that was used to create an AVI
file is required to play it back.
File Terminology
cache files (.nwc) When any native CAD file is opened or appended, Autodesk Navisworks creates a cache file
(.nwc) if the write cache option is set. When the file is next opened or appended, Autodesk Navisworks will read
data from the corresponding cache file rather than re-converting the original data if the cache is newer than the
original file. If the original file is altered, Autodesk Navisworks will re-create the cache file when it is next loaded.
Cache files speed up access to commonly used files. They are particularly useful for models made up of many
files of which only a few are changed between viewing sessions. Cache files can also be exported from some CAD
applications where a native file reader is not available with Autodesk Navisworks. Cache options can be edited
in the Options Editor (application button
➤ Options ➤ Model node).
external references External references (sometimes called reference files or “XRefs”) are shown in Autodesk
Navisworks Selection Tree as an inserted group. Autodesk Navisworks looks for the externally referenced files in
the same place as AutoCAD or MicroStation would.
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