C of G for Assembly Components 2

[carlharr]

Hi,

One of our Engineers has asked how we can display associatively the C of G information for components of an assembly, for use in a weight analysis spreadsheet.

I've added associative Body Measurements (using analysis > measure bodies) into the part navigator, as this puts a point at the component's c of g. But, I can't find a way to permanently display the co-ordinates of these points. I've tried attaching a measure to the point but it only gives the minimum distance to ABS, and also tried attaching an associative datum point on top of the c of g point, but co-ordinates don't display in the details panel.

Does anyone know how to permanently display the co-ordinate values for these points placed at component C of Gs, or any other better method to permanently show the C of G values for components of an assembly?

Thanks in advance, Carl





Regards, Carl
NX 7.5 with TC 8.3

http://www.jcb.com

 

[JohnRBaker]

Not really. Those are actually intended to be additional, expression-based schemes to help users imbed more 'parametric' content into their models. The idea is that any of the modern NX modeling features which requires that you reference either points or vectors, now have the option to use one of these expression-points or expression-vectors, which will allow users to directly manipulate these points and vectors using expressions rather than having to construct additional features simply to get a point or vector that you can parametrically update.

The new function that I'm talking about is purely a 'read-only' type function, albeit fully associative, which extracts the X,Y,Z values of a point as expressions. These expressions will be then available for use in other expressions or features, no different than something like the Measurement Expressions which get created for items like Mass, Weight, etc when using the Analysis function 'Measure Body' today.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

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

 

[carlharr]

John,

I do have a question about the new functionality, but I'm struggling to write it down here in a way that makes sense.
I'll give it a go...

Presently, analysis - measure bodies will create an associative point at the CoG of a component.
But there isn't a way to display the co-ordinate locations for these points in the ANT.

Does the new functionality, creating expressions for location of this point, either:
1. exist as part of the measure bodies command
or 2. exist as a separate measurement in the part navigator, after the measure bodies command is done (to create the point)

The reason I ask is, we are trying to tie these values back to the CofG locations of specific component instances.
So for example, the ANT needs to look something like this:

NAME MASS COGX COGY COGZ
PARENT ASSEMBLY
COMPONENT_1 14.2 100.1 99.5 45.1
COMPONENT_2 02.1 41.1 47.1 10.1
COMPONENT_2 02.1 50.4 10.2 5.1
COMPONENT_3 10.4 78.9 98.4 41.1
... so that these 5 columns can be exported straight to Excel.

How will the new measurments be related back to components from which the CofG points originate?

Thanks, Carl



Regards, Carl
NX 7.5 with TC 8.3

http://www.jcb.com

 

[carlharr]

Cowski,

Yours worked fine, I may have missed something when I did the copy and paste, its been a busy day!

Thank you very much for your help,

Regards Carl

Regards, Carl
NX 7.5 with TC 8.3

http://www.jcb.com

 

[JohnRBaker]

There is NO direct relationship between this new function and the automatic C-of-G point which are now being created when performing an Associative Measure Body. Outside of this part file, the actual X,Y,Z values of this C-of-G point, relative to the detail Master model, would be meaningless as this C-of-G point is relative to ONLY the body until you place the part in some other environment, like as a Component in an Assembly. Now the location of that point may be of use to you but only in the context of that particular Assembly, however here is where this new function can play a role, that is by establishing a set of Expressions, again relative to this particular Assembly, of those C-of-G points relative to either the Absolute space of that Assembly or to some CSYS defined in the Assembly. This does not happen automatically, but all the tools will be there for the user to establish these relationships and the associative data (the X,Y,Z expressions) which will now be there for whatever use you need.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

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

 

[carlharr]

Hi John,

Thank you for the explanation, I understand now that the new measurement ("point locator") is carried out separately to the "measure bodies" command.

However the most important question is, how do we relate this info back to the components, so that it can be displayed in the ANT?
Perhaps there's a way to create a component property at assembly level, that relates back to the new expression values?

Apologies if I'm going on about the ANT, but it is important because we're talking about assemblies with 100's of components.
As I understand it, all the "measure bodies" and new "point locator" features will be in the feature navigator. So, I'm imagining that we could rename these features to indicate the related component part number (and specific instance), in order to locate the info when required, but it would then still be a manual 'input values into excel' process. Of course its better than not having values at all, but it's still going to be pretty time consuming.

It's a shame CofG locations aren't stored automatically for all solid bodies, as a property along with weight, so that their "relative to work part ABS" location could always be displayed in the ANT!

Thank you for your help, regards Carl

Regards, Carl
NX 7.5 with TC 8.3

http://www.jcb.com

 

[JohnRBaker]

Starting with NX 8.0 it's much easier now to link Expressions to an Attribute and these can then be included in the Columns of either the ANT or even a Parts List note.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

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

 

[Toost]

Carl, If you have the Advanced assemblies license,
Do you have the customer default : Analysis-Weight managment - Generate Weight data = on ?
If so, you should have the data you request available in Teamcenter.(!)
Select a partfile in NX, RMB the node in the Assembly navigator- Properties, Weight tab, verify that the weight has been calculated. and that the part has been saved to Teamcenter.
In teamcenter, find the same Item as the above, open the Item revision, select the model then RMB - Named References. In the list there should be an UGPART-MASSPR, select it and press Open button.

Now, from here you probably need help from a Teamcenter specialist to collect the data you need.
- Maybe there is existing functionality in the Structure Manager ?

Regards,
Tomas

 

[carlharr]

Ah that's good thanks John, think I'll come back to this when we upgrade and have a look what we can do.

Tomas, I've just looked and you're right, the mass and center info is stored in Teamcenter.
Presumably the CofG is relative to the component's own ABS co-ordinates but, it's good to see the info is there, perhaps this could be shown in the ANT of an assembly (relative to assembly ABS) in the future.

Or, we could link the expressions from the new point locator measurements back to the component properties in the assembly as John says...

All things I'll have to look at when we've upgraded.

In the meantime, I've just tested cowski's (sorry don't know your name) journals with our Engineer on the real assembly.
They are working fine and providing the info we need, so we'll be using them for now.

Thank you all for your help, regards Carl.




Regards, Carl
NX 7.5 with TC 8.3

http://www.jcb.com