Offset curve in sketch - Offset is not well-defined

[stevethb]

I looked for this problem and it seems that someone has already asked it on a forum but unfortunately didn`t get an answer

The problem is with offset curve in Sketch environment. I projected some curves into sketch and wanted to offset them. I get a message saying "Offset is not well-defined for the given parameters"

Have a look at the attached prt file. Go to sketch and try to offset projected curves.

Strange thing is - when I want to offset the same curves in 3D - it works fine.

I attached prt file. This is NX9 file.

Link to original thread.

http://www.eng-tips.com/viewthread.cfm?qid=372989

 

[stevethb]

Just found out the answer.

If you do Derived Curve -> Intersect and then Project it into Sketch - then Offset Curve inside the sketch does not work
If you do Derived Curve -> Section and then Project it into Sketch - then Offset Curve inside the sketch does work

I don`t know why but it is as I described.

 

[JohnRBaker]

Generally speaking, splines created as the result of a 'Section Curve' operation are more 'well behaved' than what you would get performing an 'Intersection Curve' operation, even if the objects used in both operations are exactly the same. It's the nature of the beast. The 'rule-of-thumb' is that if the 'cutting' object is a Datum Plane or planar face, then you should try and always use the 'Section Curve' operation as this will almost always give the best overall results.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
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