NWC Files

Cache files (.nwc) are used when reading native CAD files, such as files from AutoCAD or MicroStation. By default, when JetStream Roamer opens a native CAD file, it first checks in the same directory whether there is a JetStream cache file present with the same name as the CAD file but with a .nwc extension. If there is, and this cache file is newer than the native CAD file, then JetStream will open this file instead as it has already been converted to JetStream format and therefore will open much quicker. If, however, there is no cache file present, or the cache file is older than the native CAD file, then JetStream will have to open the CAD file and convert it. At this point, it will by default write a cache file in the same directory and with the same name as the CAD file, but with the .nwc extension, for speeding up the opening of this file in future.

See for more information on why you might want to use the .nwc file exporters, which CAD applications you can export from and how.

NWC Options

JetStream allows you to enable and disable the reading and writing of cache files.

This describes the default process. The options here enable you to enable and disable the reading and writing of cache files. For example, you may want to disable reading cache files to ensure that JetStream converts every native CAD file each time it is read, even though this is a slower process. Also, you may want to disable the writing of cache files in order to save on disk space and clutter, even though the cache files are generally many times smaller than the original native CAD files.

Setting NWC options

1. Go to Tools, Global Options , and select the NWC tab.

   The Caching dialog box is displayed.

   

2. Uncheck the Read Cache box if you wish to ignore any existing caches when opening a native CAD file.

3. Uncheck the Write Cache box if you do not wish to write a cache file the next time a native CAD file is loaded.

4. Uncheck the Enable box if you wish to have no geometry compression when .nwc files are written.

5. Check the coordinates box if you wish to reduce the coordinate precision.

   Enter the value to which you want coordinates to be precise to.

6. Check the normals box...

7. Check the colors box...

8. Check the texture coordinates box...

9. Click OK to set these options or Cancel to exit the dialog without setting them.