model regeneration NX6

[Crocostimpy]

Say I suppress the last feature of a model, such as a Trim Body. When I resume it the entire model regenerates. Depending on the model that may take a couple of minutes. I don't think it should matter to Feature 4 Curve if Feature 122 Trim Body is suppressed or not. I looked through the Customer Defaults and couldn't find anything that seems to deal with this. Is there a setting somewhere so that this doesn't happen?

Mike

 

[JohnRBaker]

This is what happens with so-called 'history-based' modeling. When you make any sort of edit, even if it's something as innocuous as suppressing the last feature in a large model you will have to playback the entire model tree. That's just the way it works, period, and NX is not unique as this is a characteristic of virtually ALL history-based modeling systems.

Now that being said, there are a few things which you can do to mitigate this situation.

First, and the oldest option is the setting of so-called 'roll-back marks' in...

File -> Utilities ->Customer Defaults -> Modeling -> General -> Update

...where you can set the number of 'Features/Mark' (note that this can be overridden during a session in Modeling Preferences).

Now what happens is that during a session of NX when you edit a model for the first time a full update is performed and a 'roll-back' data-record is created which is held in local memory while the part file remains open. This data-record is used for a couple of things including making sure that model edits are undone correctly when you perform an Undo, as well as provide the 'road-map' for performing future model updates when it's needed. Now the 'Features/Mark' setting, which we recommend that you start out setting at something like 5 or 10, will add explicit roll-back marks each 5 to 10 features so that when you perform an edit, rather than starting the update at the first feature, it goes back from the feature being edited it the next 'roll-back mark' and starts the up date from there. So for example, if you had already done an edit and your model had already performed a complete update, when you would have suppressed that last feature, the system would gone back at the most 5 to 10 features (depending on what you had set) and it would have started the update from there. Now there is nothing preventing you from setting this to 1, except that it will cause this in-memory file to be larger and the benefit would be very marginal at best.

Now starting with NX 5.0 we've added another option which will help reduce the time it takes to perform that first update when editing a model in a new session of NX. Remember that 'roll-back' data-record I mentioned above, well it normally gets deleted when you save/close your part model and it has to be regenerated the first time you perform an update the next time you open the part file. Well you can now go to...

File -> Utilities ->Customer Defaults -> Gateway -> General -> Part

...and toggled ON the 'Save Data For Fast Rollback and Edit' option so that this data-record is saved with the part model and therefore when you reopen it in another session this date-record is loaded into memory and you are automatically ready to make updates based on the value of the 'Feature/Mark' setting. This will save the time it takes to create the initial 'roll-back' data-record in your new session.

Now there a few things that you should be aware of. First, this will increase the size of the part file on disk (the memory usage will not be effected since the the 'roll-back' data-record is going to eventually get created anyway) which also means that it will take longer to open and save your part files since this extra data has to be copied from memory to the disk. Therefore, while this generally improves your overall performance when working with models that are still under development, once your designs are complete and you are ready to archive your models, it's advisable to go to...

File -> Options -> Save Options...

...and toggle OFF the 'Save Data For Fast Rollback and Edit' option before you save your project files.


OK, now that we all have a better idea of how so-called 'history-based' modelers work, that might help to understand why we've recently introduced Synchronous Technology which provides you even more control over how and when models will update, even going so far as to using techniques which involves history-free modeling where the size of the model (the number of 'features') has very little effect on the time it takes to perform an edit since there is no feature tree to update (the model structure is flat with features which do NOT depend on other features when they update, therefore updates are very quick).

Anyway, I hope this helps.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[Crocostimpy]

I figured it was probably a programming thing and it couldn't be changed. I'll try out your suggestions and see how it goes. Thanks John.

Mike