Assembly constraints 1

[RML1]

I have just organised updating from NX5 to NX7.5 for our 9 seats of UG within the company. Most of the changes are logical and easy to understand. However, I missed whilst testing it that assembly mating conditions has changed to constraints (partly becuase it happened in an earlier release and also the icon is the same!).

The idea that it does not matter which way round the constraint is created is good and I think I am up to speed with the new system. However I am struggling with the visibility and user friendliness. Hopefully some of this will ease with time and familiarity.

What concerns me is my series of suspension models which have been refined over the last few years. These use simple models of each component (wishbone, upright, links etc) with spheres at all the articulation points. These are mated in an assembly with various constraints using quite a few expressions contolling distance constraints and plane positions, allowing the model to be adjusted for camber, toe, bump, steering etc from the expressions. This is used extensively for some basic geometry analysis and to move the higher level model for clearance chacking etc.

I have yet to try converting the constraints over for these models. In the short term at least it would be benificial to be able to keep working with the old mating conditions, until I can sucessfully convert and work with the new method, is this possible in NX7.5?

Longer term is there a way to group, re-order and rename constraints to help with visibility? The dependancies tab showing details does help a bit, but is hardly user friendly. Anyone else found this change over difficult? I know they are not going to go down well with my colleagues when they get into it next week!

 

[JohnRBaker]

As to your first question, NO, you can no longer create or edit (other than editing expressions which drive a Mating Condition) the Mating Conditions from a legacy model. They will continue to update properly as you make changes to components and such, and you will NOT need to convert them for them to remain valid, however all changes and/or new work must be done using Assembly Constraints.

There are techniques which you can use to help manage constraints, such as filtering and the use of the Dependency panel, but for the next release of NX we have added an additional dedicated 'Constraint Navigator' which will allow you to organize Constraints using several criteria such as by Component, by Type, by Status, etc. And no matter what scheme you used to organize the Constraints, you will still have the option to sort using the columns in the Navigator. For example you may want to orgnaize by Component yet still list by status. Or something new that was added, you can now list by the DATE the constraints were created.

And while it's still possible to see the Constraints in the Assembly Navigator, as you do now, with a dedicated Constraint Navigator, you now use the Assembly Navigator just to display and manage the assembly structure, while quickly being able to switch to the Constraint Navigator WITHOUT having to expand and collapse sections of the Assembly Navigator.

Now that being said, we have not yet ready to support an explicit user-defined 'grouping' mechanism for Constraints, but that's one of the things being considered now that we have this new dedicated Navigator where a capability like that would be easier to manage.

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.

 

[RML1]

Thanks for your reply. The changes (to NX8?) sound promising, although for me the best way to manage constraints is almost there, by clicking a component and seeing the constraints relevant to it in the dependancies panel. The only problem with this at the moment is that ALL you want is a list of constraints. You have to remember to click details and I don't understand the need or use of the child and parent folders (I thought it didn't matter which is parent and child now?).

One other slight issue I noticed is that if you delete a referance object (such as a sketch or plane) that you have used to constrain a part, you used to get a warning that it is referanced by a mating condition. You could then see details of this in the information window. Now it doesnt say anything, the only indication being a red cross next to the constraint, which you might not pick up straight away and I can't seam to find a way of telling why it has failed.

Overally I get the itention of the new system and can see the long term plan. Unfortuently it does feel a bit like it needed more work before releasing and for us will take the shine off an otherwise good upgrade.

 

[JohnRBaker]

As far as the 'parent/child' issue, it's a bit of a left over and it not really refering to the constraints themselves.

As for the no warning on when a referenced object is deleted, part of that problem is that the old Mating Conditions were actually 'timestamped' like feature are and so there was no real way to prevent these downstram failures from showing-up in this mechanism. Now that there is no 'timestamp' relationship, there is nothing for the existing mechanism to report since we're dealing with a totally different scheme. As for comment about not knowing what caused a failure, that is also one of the issue which we have addressed in the now when a constraint fails you the icon used to highlight the failure will actually indicate what type of failure was it and even whether it's something that needs to be explicitly fixed or was the result of something eles that when it's resolved will cause this constraint to become valid again. Many times it's not a problem with the constraint itself but with the component, such as it not being properly loaded or something, and once this is has been taken care or corrected the constraint will update correctly and will no longer be flagged. You will be able to see and even list the 'failed' constraints in such a way that it will be obvious which constraints actually need attention and which ones are simply waiting for something else to be done.

Anyway, what you're seeing is the natural maturing of functionality based on both feedback from customers and work done in other areas which now allows us to handle some issues better than we were able to initially.

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.

 

[RML1]

Thanks again for the reply, it sounds like this is a work in progress and will improve. Having had more of a play with it I am slightly less concerned.
The dependencies view down the bottom is actually the best way of seeing the constraints related to a component (not dissimilar to Solid Edge, which was good in this area). It just needs a few refinements, such as removing the parent/child folders and not having to hit details to show the constraints. Probably the biggest one though is I want to be able to rename a constraint, which you can do, but I need the custom name IN FRONT, or INSTEAD of the default description which currently cannot be altered. This means you can identify a constraint more easily, without having to scroll a long way right.
I am therefore unlikely to use the constraint section in the navigator and moving it to a separate one is not much of a concern as long as they stay in the dependencies panel, because that’s where I will use them.

 

[JohnRBaker]

While we have not changed the way the 'User-Defined' name is appended to the Constraint's name, in the new Constraint Navigator you WILL have the option to include a column which will show ONLY the 'user' portion of any 'renamed' Constraints, and like any other column, you can toggle the column's header to force a lexical sorting of the contents.

As for the use of the 'Dependencies' panel in the Assembly Navigator (or for that matter managing your constraints from Assembly Navigator as you're doing now), while we have not changed that in any way, I suspect that once you start using the new Constraint Navigator you may discover that it no longer provides you with anything that you couldn't now do in a more direct manner using the tools and options available in the Constraints Navigator without having to open additional panels or sharing space with Assembly structures or other items found in the Assembly Navigator which do not pertain to Constraints.

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.

 

[RML1]

What update is the constraint navigator due in?

 

[moog2]

one way i use which may help you, is to move certain sets of constraints to different layers, then when you turn those layers off, the constraints turn grey in the navigator.

 

[eex23]

http://www.eng-tips.com/viewthread.cfm?qid=290124&page=22

maybe this discusion will be usefull.

 

[JohnRBaker]

The new Constraint Navigator will be part of the next full release of NX, expected to be available around the end of Summer. We have just started the second week of Beta testing so we are on schedule to make our planned release date.

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.