Showing results for 
Search instead for 
Did you mean: 

Modelling Conventions in NX




I am new to this blog so please bear with me...


I have just started at a new company, and have been recruited with the task of improving modelling practices and utilising the master model for other operations such as inspection and maintenance manuals.


The company have been using UG/NX for many years, and have a massive amount of legacy models that have been produced with curves, then modified may times with synchronous technology.


They have just started a new project, and want to use PMI to make downstream operations easier. In order to do this, the models become much more important and must be correct.


When it was suggested that some of the models may need to be redone as they have got so many unmodifiable features, it was suggested to convert everything into a dumb solid and use more synchronous operations to modify anything in future.


To me this is a truly scary prospect, as I think models should be able to be modified by changing the base features, rather than adding more…

My questions are, what are people doing with bad models, what are peoples thoughts about modifying parametric models with synchronous and what are the drawbacks of this?


Using NX 9

NX User/Admin for 13 years.


Re: Modelling Conventions in NX

Siemens Phenom Siemens Phenom
Siemens Phenom


I can share some experience of mine (given the fact that you already have a good exposure to NX ..i am not sure if this will add any value to the thread or not ..but still)..

I used to work heavily on surfacing projects long time time back and for a single model sometimes it took so many features/iterations to build up the model that the part file size crossed 100 MB size even... Editing and updating took quite a long time and also if there are lot of users working on the same part file it gets worse some time.

Complete feature associativity is good but it takes a toll on performance also (opening the file/ doing edits etc.) so in my opinion as the model size (feature wise) builds up should think of more smart and intuitive ways to tackle it. Synchonous is one of the intuitive tools that come in quite handy specially for the imported models and the ones with dumb bodies. Let us say if some user has already created a blend corner manually in an old NX version (i mean using patch surfaces or making it a mix of both solid and surface modeling) ...will you prefer editing the same or deleting it using synchronous tools and recreating it downstream using new NX feature (which was not there in previous versions)

Coming back to my work experience...As a thumb rule we kept the model feature history intact to some extent (let us say the base features..big patches or the main design intent)..after that we created one more part file (where the model from the first part is imported as a dumb body) and did further operations on it till we get the desired model...if there are some changes to be made in the first part...we will do it and then replace the new dumb body in the second part file (where the model from the first part is refered to)..

One more option (for better associativity robustness) could be to take the wave link of the first model in the second model and work accordingly. This way at least you need not replace the body again and again.


I will not say that it is impossible to make a good and fully associative model (frankly speaking i have seen some very fine models which worked marvelously as far as associativity is concerned but i will say that it depends on user to user)


There are lot of good practices and i am sure experts on this forum will share more on it.


Best Regards




Re: Modelling Conventions in NX




Thanks, its interesting idea of creating a copy with a representive dumb body to improve load times, possibly with wave linked geometery to the existing model. (Although there is hesitation over previous problems with that too!!)


I agree Synchronous is a very powerful tool for modifying dumb data, especially if its used well.


The company agree that the model must be 'good' in order to use PMI effectively, we just need to arrive at a conclusion of what determines a good model!! I dont feel history free modelling is a good idea.


The biggest problem is 'we have always done it like that' attitudes, rather than exploiting better methods as the software has improved!





Re: Modelling Conventions in NX

Valued Contributor
Valued Contributor
well if I come across bad model I switch to History Free (pre NX11) or Remove Parameter (NX11). Then you can switch history back on (pre NX11) and use Dimensioning tools from Sync.Modeling for base geometry and Resize tools for the rest. Model History this way is very neat.
I doubt there is more rational way, unless you have a mastermind of that bad modeling to clean up his mess Smiley Happy

What I consider bad model - offset on offset on offset, sketching all over the place (even though feature is available), extruding those sketches in mysterious ways.
If you have in mind inaccurate models... still easy to fix with Sync.Modeling. But inaccurate model in CAD system is plain laziness Smiley Wink