Question: What is an .nwc (cache) file?
Answer:
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.