Boundaries vs.Extract

[giumel]

I am new in this forum and may be my ENGLISH is not as good as
yours, anyway i will try to explain my indecision
about creating curves.

If i need boundaries curves there is the appropriate Command
but personally I prefer use the EXTRACT command.

I TESTED both command during REPLACE scenario.

The rusults were ...impossible to say BOUNDARIES IS BETTER THAN
EXTRACT and viceversa.

so I wish to know if anyone can help me to understand which is
the command MORE STABILE during the REPLACE and UPDATE PHASE.
I am using V5R16

thank for all

 

[flangewiper]

Personally I use Boundary for curves, Extract to get faces or surfaces and occasionally to get individual curve elements out of sketches and I don't generall have problems when I come to replace element. Not sure what anyone else uses but this does the job for me.

 

[solid7]

I've never personally noticed a difference in the 2 for individual curve extraction. Not sure if there is a marked difference for tangential, or point continuity either. I'm not an expert, though - I'd like to hear some of the logic and reasoning for using one vs. the other. (other than pick entity vs. edge)

I use the boundary function only when I'm trying to find openings or gaps in Join surfaces.

I've never slowed down long enough to explore the differences. Hopefully more of you will discuss this, so I can learn...

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CAD design engineering services - Catia V4, Catia V5, and CAD Translation. Catia V5 resources - CATBlog.

 

[5050t]

Using "Boundary Definition" you can limit (Limit1/Limit2)your curve using a point.

To find openings or gaps in Join surfaces use "Connect Checker" and select "Internal edges"

 

[solid7]

Boundary curves is (in my opinion) a much better way to find the openings and gaps. They display clearly, and create real geometry. Connect checker leaves analytical data, which I have no interest in, 9 times out of 10.

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CAD design engineering services - Catia V4, Catia V5, and CAD Translation. Catia V5 resources - CATBlog.

 

[Abaddon]

The Boundary command is just a specialised verion of the extract command. Computationally they do the exact same math to create the intended curve, but the boundary command adds extra flexibility for constraining the length of your curve.

I do the same thing as "flangewiper". I use "Boundary" to get edges, and use "Extract" to get surfaces and faces.

 

[giumel]

Thanks a lot guys regarding this.
I wish to share some picture taken by my scenario
to show you what happened when I built a point
on the EXTRACTED curve and replaced the surface.

now the problem is:

HOW CAN SHOW YOU MY PICS??

GIUMEL

 

[jackk]

Kapitan submitted this helpful post last year

http://www.eng-tips.com/viewthread.cfm?qid=127497

 

[sqi]

GSMExtract points to a BRep feature whereas GSMBoundary points to the spec itself, that's why you are more liable to have unstability or problem at replace.