Playback not the same as Make Current Feature?

[MarvelouZ]

Hi,

As a part of models release process I need to check model integrity with Playback tool. I have noticed that it doesn't work exactly the same as Make Current Feature on the first operation and then on the last (during which NX just updates the whole model anyways). What is the difference in those methods?

I have also came across models that run flawlessly in NX7.5 playback but have errors in 8.0 playback feature.

This is to be honest some strange behavior I face, because when I open the model it's in tact, then when I run playback, some operations fail, causing whole model to change geometry. It's like NX is telling me "I don't know how these operations worked before, but now I can't let it go like that" lol. I sense lack of logic here.

Also is there any correlation between Playback feature and Examine Geometry test? I would expect model with passed examine geometry test to finish playback without any problems...

Unfortunately I can't attach any models due to copyrights protection.

Can anyone shed some light, how does it work?

I work on NX8.0 right now.

 

[Xwheelguy]

Make Current Feature just rolls the model "back in time" to the selected feature. The newer features are not actually supressed, but rather in an "inactive" state. You can use this command to "insert" additional features before others. It's quite useful if you have your Part Navigator set up to be viewed in Timestamp Order (the order in which each feature was created).

Feature Playback goes back in time and allows you to control the increments as the Playback goes forward in the model.

Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[MarvelouZ]

So if I get it right, Playback suppresses the features while being performed, while Make Current Features doesn't.

I still don't understand why it happens, that in this way suppressing a feature has another effect on its correctness than making it temporary "inactive" and bringing back to life.

 

[Xwheelguy]

You might be over-thinking this a bit. And my apologies for not addressing your additional inquiry about Examine Geometry.

I don't know how to explain the differences between Feature Playback and Make Current Feature any better than I already have. They work a bit differently, but in some ways, they may seem to work the same. Playback automatically goes back to the beginning and allows you to control whether you step forward ONE feature or if you skip over several features using a dialog that resembles a player - it's NOT a geometry checker. It can be used to see if the model will UPDATE correctly though. It's pretty simple. You create a few features and Playback allows you to go back "in time" to the first feature and recreate it, then the next and the next or skip from first to tenth. It gives you options for addressing any issues that you may encounter when playing back the model history.

Make current feature does NONE of those things. It simply rolls the model back to a single point in time (the feature you selected to make current). Then you can pick a completely different feature and make it the current feature. It may SEEM like you're suppressing features, but I promise you that you are not. Use your Part Navigator and see what they do - can you not SEE the difference? It's pretty much what you see is what you get.

Neither of these commands suppresses features. That is COMPLETELY DIFFERENT. If you suppress things, later features may also suppress while others might not. Suppress is affected by Parent/Child relationships. If you suppress a hole with threads and chamfers, the children (threads, chamfers) will also be suppressed, however the body to which the hole, threads and chamfers are applied will still appear in the graphics window.

To be honest, I only ever use Make Current Feature unless I've just not paid any attention to the order in which I'm creating features, which I haven't done in over a decade because I've learned it's wise to make things in a logical and ordered manner if I hope that someone else can sit down and perform editing on a model which I've created.

Examine Geometry does exactly what it says it does - it checks the geometry for whatever you select in the dialog. It has NOTHING to do with specific features, but rather geometry quality. Geometry quality is completely differnt than modeling technique using features. You can perform an Examine Geometry check on a model without Features (such as an imported solid body).

If you're still having issues understanding these commands and their differences, then my only suggestion is that you read the Documentation to clarify things a bit more.

Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[ewh]

A simple check used years ago (but no longer preferred) was to reorder the feature tree, often by switching two independent features where there should be no impact on the model, such as independent datums. This was good for those of us that tended to be a bit anal about the feature numbers in the model, as it would reorder the numbers and eliminate any gaps.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[cowski]

When I started using NX (or rather UG at the time) our CAD guru had 2 conditions that had to be met before a part was released:
[ul][li]must pass examine geometry checks (face and body checks)[/li]
[li]must be able to suppress and unsuppress the entire feature tree without update errors[/li][/ul]
I've seen lots of 'inexplicable' behavior in parts between versions and within the same version. Features that would create with no problem would error out when suppressed and unsuppressed (even immediately after creation!). However, I can't remember a single case that couldn't be solved with a change in the modeling strategy (usually minor changes, occasionally not...). Sometimes when a feature won't create/update, it is because of bad underlying geometry (something that doesn't pass the examine geometry checks). Just the other day a coworker had a unite feature failing with a message of "through face does not intersect..." when clearly it did. After running examine geometry, he found some body consistency errors. Once those were fixed, the unite worked fine.

Bear in mind that just because your model passes examine geometry tests when you are nearly finished with the model, doesn't mean it is good geometry all the way through the feature tree. Sometimes a problem section of the model gets "modeled away" later. Problems may crop up in the middle of your feature tree that you don't see later. If/when these problems pop up, run examine geometry on the entities involved.

As for the differences between "make current" and "feature replay", if you make no changes when using "make current" it is equivalent to using "show and hide"; NX updates the display but doesn't re-calculate the underlying geometry. You want to force NX to recalculate the geometry to really evaluate your model (I think the term used was net-null update). There was some debate years ago about how to best accomplish this; I think ewh hit on it with a feature reorder. If I remember correctly, the feature replay didn't force a true update (though this was years ago, it may be different now).

www.nxjournaling.com

 

[MarvelouZ]

Thanks for the replies guys, this is much clearer now.

2 more questions to what Xwheelguy said.

1. When adding new features in the middle of the tree should I Make Current Feature there or use Playback to get to this point and then construct or it does not matter?

2. Is Playback somehow placed in check-mate analysis? I only see there Update All Features option and Check Feature Rollback option, does it cover what I need?

 

[Xwheelguy]

For question #1 in your last post, I would recommend using Make Current Feature.

I'm sure not every NX user will share my opinions, but I'd worry more about having a finished model first, then going back and looking for and fixing any issues that might reside after doing a complete update and/or Examine Geometry.

Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[ewh]

I would also use "make current feature"; not because using playback is wrong so much as old habits die hard, and this method has always worked well for me.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

 

[cowski]

1) Either way works, but "make current feature" is more convenient.

I'm sure not every NX user will share my opinions, but I'd worry more about having a finished model first, then going back and looking for and fixing any issues that might reside after doing a complete update and/or Examine Geometry.

I agree with Xwheelguy. Finish it, check it, ship it.

www.nxjournaling.com