CG on a face

[sourcec0d3]

Hello all,

I have been searching on the forum here and haven't really found a solution to the problem I'm having and was wondering if someone may be able to help.

I want to find the CG of a single face and want to create a point on it(associative point if I could!)

Thanks for your help!

 

[JohnRBaker]

What version of NX are you running?

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
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To an Engineer, the glass is twice as big as it needs to be.

 

[sourcec0d3]

Thanks for replying John, and sorry about that! Version 8.0.3.4

 

[cowski]

Are we talking about planar faces, or something with an arbitrary 3D shape?

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[sourcec0d3]

A flat planar face

 

[cowski]

Analysis -> section inertia will report the CG, but it is not associative. When selecting 'curves' for input, you can change the filter to 'face edges'.

If you don't see the command in the menu, try changing to a role with 'full menus' or customize your current role to add it.

www.nxjournaling.com

 

[JohnRBaker]

You can also use...

Analysis -> Advanced Mass Properties -> Mass Using Curves and Sheets...

...but if the 'face' isn't a Sheet Body you'll have to first extract one. Then use the 'Thin Shell' option indicated above and there is an actual option to create a point (non-associative) at the CG. Now this will work with planar and freeform faces (sheets), but except for planar faces (sheets), the CG is NOT the same as the CENTER of the face, so keep that in mind.

Now there is another function which will allow you to create an ASSOCIATIVE Point at the 'parametric' center of the face. By 'parametric' I mean where the 'U' and 'V' face parameters are equal to 50%. However, this will only come close to what you may think of as the CG for faces which are NOT 'trimmed'. That is the face has 4 edges and if you were to extract a sheet body and perform an untrim operation, the object would not change in size or shape. Anyway, this function can be found at...

Insert -> Datum/Point -> Point...

...and you use the 'Point on Face' Type and you set the 'U' and 'V' Parameters both to 50.

Anyway, gives these a try and see if this gives you something that you can work with.

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.