If we're talking about models which are still under development and will likely be changed several times before being 'frozen' and released to production, you amy wish to go to...
File -> Options -> Save Options...
...and toggle ON the 'Save Date for Fast Rollback and Edit' option. This will help to improve that first time (after opening your part file) update of your model after an edit. The reason that I say this may be a consideration IF the model is not yet ready for 'release to production' is that this will cause the saved part file to be significantly larger, which may be fine while a part is still a 'work-in-progress', but which would waste file space if parts were archive with this option ON.
Another setting that can have an effect on update performance is the 'Features/Mark' setting in the...
Preferences -> Modeling -> Update
...dialog. Now as to what to set it at, for that absolute biggest impact you would set this option to
1, however that will require more memory and will also cause your part files to require even more disk space if you've also set that option I discussed on the previous part of this post. Generally speaking, if you are working with large models (in terms of the number of features) at setting of 10 will probably give you just a much of a benefit, but you could try 5 as a compromise.
Now there is one more issue which is sometime a bit controversial and that's what have you set as your modeling tolerance to. Out-of-the-box, the modeling tolerance has been set for what is considered to be a good nominal value for most of our customers,
0.001 inches for Imperial Unit parts and
0.0254 mm in Metric Unit parts. The only time I would AUTOMATICALLY consider making an across the board change to this setting (in Customer Defaults) would be if if designing and manufacturing very small or very large products, perhaps something like watches at one end and locomotives at the other end of the spectrum (although now that we're selling to more ship builders, perhaps something like a submarine or an aircraft carrier might be better examples of where the upper limit is). If you're somewhere in between these examples, I would stick to the above quoted values.
Now one thing to remember is that not all modeling operations are effected by this tolerance setting but those which are generally include in the dialog a parameter entry where you can override the default tolerance. In those cases this tolerance will be included as a parameter of that feature and which can be edited later on. It also means that once a feature has been created, going back and change the default tolerance, either in Customer Defaults or under Modeling Preferences, this will have NO effect whatsoever on any existing feature.
So our advice, unless you really are working at or near one of the extremes I sited above, you should leave the defaults alone and only if while creating a feature that you feel that a difference tolerance would be more appropriate then make that change for THAT feature only, don't bump up the global tolerance.
Now the reason that this can have an impact on performance is that if your model contains complex faces, either created as B-surfaces or as the result of complex swept or blend features, have too small a tolerance can cause the geometry being created (edges and faces) to be more complex than it needs to be (more data points being needed to define the shape), which will BOTH increase the size of your model in terms of the memory needed to save it and work on it during an NX session. Also this will slow the update as more data needs to be evaluated when the feature updates and the resulting geometry may require additional time and memory in order to be properly rendered, particularly when computing mass properties and things like Hidden-Lines.
Anyway, these are a few things that you may wish to review which could have an impact on model update time.
Also note that there are some things which are not directly related to model update time, but could still give you the feeling that overall performance is poor and that could include display tolerance settings, system memory, graphics cards, disk access speed, etc.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
