NX9, divide face command, normal selection

[AnotherMike]

Hi Guys,

I meet a strange problem. I project the four edges of a rectangle planar face A to another planar face B and then use these four projected curve to divide the face B. However,when diving face, you can only select "Normal to curve plane". If you select "Normal to face", it will not work and give a error. Could anyone give me an explanation?

 

[JohnRBaker]

I tested this using NX 9.0.0.19 and while I don't have your model I tried to create what you decribed, but whatever, I was NOT able to duplicate your error condition. Can you provide a sample model where this 'problem' is manifesting itself, and if you can do that, can you at least provide a picture showing what your model looks like and how it your projected curves appear on the face that you're attempting to sub-divide?

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
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[AnotherMike]

Hi John,

I have built a simply model that show the same problem. I attached the part file and a picture. The model just contains two block.

 

[AnotherMike]

part file

 

[JohnRBaker]

OK, I figured out what's happening and how to avoid it, just that I can't give you the technical reason WHY it's happening. Of course I could always track-down the developer(s) responsible for these functions and I might even get an explanation, but then I'd HAVE to understand it myself before I could pass it along... ;-)

Anyway, the way to avoid this problem is that when you create the 'Projected Curve' feature, in the 'Settings' section of the 'Project Curve' dialog, change the 'Join Curve' option to 'No'. If you use any setting other then 'No', the result will be a single spline curve. While that might seem to be efficient because you end up with ONE spline versus FOUR lines, it could prove to be problematic since there were those 'sharp corners' (and if I did manage to talk to a developer, I suspect that something along those lines would be the message that I would get). Now this doesn't mean that you can't use a closed spline curve to Divide a face, just that it can't have sharp corners.

So, in this particular situation, avoid using the 'Join Curves' option when you Project the curves and you should be good to go.

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.

 

[AnotherMike]

Thank you John.
Yes, when you select not join curve when projecting, it allow you to divide the face. It is interesting that even the closed spline has sharp corner, you can still use "Normal to Curve Plane" or specify a vector, but you just can not use "Normal to face". Hope this can be improved in later version.
However, the reason i use "join curve" when projecting is sometime if you do not join these projected curve,you may get the wrong result. Please see the file i attach.

 

[JohnRBaker]

Like I said, the real reason is probably something that neither of us would fully understand, even if the developer explained it to us in 1 and 2 syllable words

While I haven't verified this, I suspect that if you had included some very small fillets are the corners of the profile to be projected onto the face that you wish to subdivide, this would have worked fine even if you joined the curves and used the Normal to Face option.

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.