Change edge - Unable to change edge 1

[PrintScaffold]

Greetings all!

So far I haven't been able to make "Change edge" command work. Whatever choices I make, it's always "Unable to change edge" in the end. I'm quite puzzled. Could please somebody show me the light?

 

[Toost]

Change edge ?
Direct Modeling Move Edge NX 9 ?
NX version ?

Regards,
Tomas

 

[PrintScaffold]

Change Edge is Change Edge.
Edit > Surface > Change Edge.
NX8.5

Overally, I'm interested to know how can I fix the tangency of two sheet bodies. I think Change Edge is the command I need. Am I right? Any other options?

 

[cowski]

A screenshot, or even better, an example file would help.

www.nxjournaling.com

 

[PrintScaffold]

Here's the example. But - for me at least - it could be any, because I really don't understand how this function is supposed to work. Because it does not for me.

 

[JohnRBaker]

To start with, virtually none of these sorts of surface editing functions will work with trimmed surfaces. The issue is that the edges being modified must be the actual edge of the mathematical/topological definition of the surface, NOT some arbitrary trimmed edge.

And second, I would look at using something like...

Edit -> Surface -> Match Edge...

...for something like you've described. Primarily this is because 'Change Edge' is an older, 'legacy' function which is being replaced by functions like the aforementioned 'Match Edge, a newer function with a modern interface.

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.

 

[PrintScaffold]

Thanks, John!

I'm not that proficient yet with the concept of a trimmed surface... although I have an idea of what you are talking about. If I need to match the sheets as I described, but they are trimmed, what can be done there?

 

[JohnRBaker]

To 'Untrim' a surface, go to...

Insert -> Trim -> Untrim...

Note that this will NOT remove your original surface but rather will simply create an 'Untrim' feature which will be a child of your original surface so it will still be there if needed. There is however, an option to automatically hide the original surface so as to not confuse anyone.

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.

 

[PrintScaffold]

But that is going to change the shape of the surface, right?

 

[JohnRBaker]

It will not change the 'shape' but it will change the size (it will now have added back-in whatever got trimmed-off before).

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.

 

[PrintScaffold]

So basically surfaces get trimmed to the rectangular UV shape? And that means that I can't match any edge, but only U or V edge?
Once again, I'm not that good and this UV business yet. Does it means that only a rectangular-bounded surface is being untrimmed?

 

[JohnRBaker]

Basically.

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.

 

[PrintScaffold]

Then is it possible to reparametrise the surface so that trimmed edge becomes 'raw' U or V edge that can be matched?

 

[JohnRBaker]

In this particular case I created new surfaces using Surface Thru-Curve Mesh selecting the edges of the original surfaces as the 'curves' and the used Match Edge to make them line-up and be tangent to each other, as seen in the attached example.

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.

 

[PrintScaffold]

Looking good! Thanks, John!

Is this approach applicable to the most cases? Will newly created surface be always untrimmed? Or does it depend on a particular shape?

 

[JohnRBaker]

Very few NX surface creation functions result in a 'trimmed' surface. Certainly the ones that references curves, such as Swept, Thru-Curves, Thru-Curve Mesh, Ruled, etc., these will always result in an untrimmed surface. Now extracting faces from other models, such as a solid body, will almost always result in a trimmed surface. Also, importing surfaces into NX will often result in trimmed surfaces.

As to whether my approach of using Surface Thru-Curve Mesh will work in most cases, well that depends. If the surface is already basically rectangular and the shape pretty well matches the four edges, like was the case with your example, then yes, it's work in many cases. However, if there are extreme changes in shape or other 'features' not consistent with the edges then you you may have to create some cutting planes and create intermediate interior curves representing these areas of more complex shape before you could use something like Surface Thru-Curve Mesh.

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.

 

[PrintScaffold]

Thanks, John!