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BREAK EXTENSION LINE 4

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bonster

Electrical
Jan 21, 2008
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I am a NX5 user. How can I put a break in an extension line
in the case where two extension lines cross?
 
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Zoom up on the drawing view where you wish to add the gap so that you can see what you doing.

Then go to Insert -> Symbol -> User Defined Synbol... and when the dialog comes up under the item titled 'Use Symbols in:' select 'Utility Directory'.

When the list of symbols come up scroll down till you get to a series of 3 named 'GAP06', 'GAP125' and 'GAP25'. The larger the number of the larger the gap so you may have to experiment a bit (note that even though the numbers appear to correlate to Imperial units (Inches) there results will be the same in English or Metric drawings.

Now go the bottom of the dialog and you will find 4 icons, you want to select the one on the far left, labeled 'Add to Drafting Object'.

Now select the dimension that you wish to add the 'gap' to (you can pick it anywhere just as long as it highlights).

Once the dimension is highlighted now place your cursor just a little below where you wish the gap to be created (actually this will be the bottom of the gap if the extension line is vertical) and select.

Now you have a gap. Repeat as needed.

And before you ask, NO, they are not associative so if you move the dimension and the gap needs to be moved, you'll have to delete the current one and create a new one.

I know this sounds old and archaic, but that's only because it is.

John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA
 
To move the gap: Edit Component - Move Component.
If there is only one gap on the extension line it will highlight, if there are more than one gaps, select required gap by mouse clicking.
 
Add one more to make this an ER! Gaps are VERY awkward now (unpredictable direction, for example, as well as snapping to some unknown, invisible point on the leader line, NOT where you pick).

-Derek
DL Engineering Services
specializing in CAD Design Consultation Services
 
Thanks Bishbosh,I always wondered how to move the darn things once they are placed.
The way I do it is change the dialog to length and height instead of scale and aspect ratio_Once it's set to length and height,I set it to .90 x .90 (for a four place dimension),and then it's a square box so to speak ,so it doesn't matter what direction it's going.I line it up roughly with the existing extension lines and it works pretty good.
I've finally set up a macro to change automatically to that setting and copy that macro into every working directory(along with others). Then it's just CNTrl/Shift P and pick the gap macro and add the gap. It's almost effortless now.
I agree though, it's one of the least intuitive functions in NX.
 
Derek,

Point well made I think moving it works okay, but the initial positioning origin lacks for some visibility and control over where the gaps are likely to apply. I'd almost always have to move them until they center on the dimension/extension line that it crossing over.

You want to write an ER they have it say that where dimension lines cross then good drafting practice is supposed to be that you show a gap, therefore the CAD system should just do so. You would of course need to be able to toggle this one and off so that people have control of how they adhere to standards but I wouldn't just tinker with something 20 years old that still works kind of okay for most people who bother with it only infrequently.

Or you could just write a macro or something to help to speed up the process. It has been that way for so long I wonder if it might not even still be supported by GRIP. My idea for that would be you add the gap, then immediately jump into the editing component so that you can move it, based on the fairly accurate assumption that you'll always have to move it in order to line it up correctly.

Best Regards

Hudson
 
I've held my tongue until now.
Gaps are not always good drafting practice. Gaps are a low value added feature. On board drawings, they were useful due to smudging graphite. Per ASME Y14.5-1994, the only time gaps are used is when extension lines are close to or cross arrowheads, then it is permissible, not mandatory.
Para 1.7.1.4 "Crossing dimension lines should be avoided. Where unavoidable, the dimension lines are unbroken."
Para 1.7.2.1 "Where extension lines cross must cross other extension lines, dimension lines, or lines depicting features, they are not broken. Where extension lines cross arrowheads or dimension lines close to arrowheads, a break in the extension line is permissible."
If I caught someone under my supervision spending time adding gaps, they would be told to stop. The time spent in this thread shows that too much effort is being made for something that is essentially insignificant. There are MANY more areas of a good drawing they should be expending effort on than adding gaps, and I for one would rather my maintenance dollars be spent on more fruitful endeavors.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]
 
ewh

I agree, I agree 100%, they are a waste of time and are considered bad practice here due to the fact they are so "dumb". If they were automatic like JRB suggested, so there was a dead zone at a predetermined distance parallel to the dimension line, and would be fully associative, then fair enough, but otherwise we leave them well alone.

Simon

Best regards

Simon
 
I disagree that they are insignificant. But I do agree that they should be used only in cases where they must be used, such as when an extention or leader line crosses an arrowhead.
I have been on UG for 20 years, but for 10 years before that I drew on the board - there was much more strict rules for drafting than there are now, and the drawings looked much better than they do now. There is no reason (except laziness) that better drafting practices cannot be adhered to - especially when those bad drafting practices lead to costly errors, or costly time in the shop trying to figure out what the drawing says. Sorry ... I drifted off the subject.
 
I agree that there are occasions where gaps are justified. I have just found that those occasions tend to be few and far between. I came upon such a situation this afternoon. What I don't like to see is someone wasting company time wrestling with putting gaps in everywhere lines cross simply because they cross, and then trying to maintain them. That is not good practice, or a good use of company time. The arrowhead situation can usually (but not always) be overcome by thinking out the dimensioning scheme so that the situation does not present itself. That is good drafting practice, and seems to be rarer every day. If todays drafters had spent time repeatedly erasing dimensions because of poor placement, I don't think they would be so nonchalant about lines crossing on a CAD drawing (which is unfortunate considering how easily we can relocate them now).
The current method provided may be cumbersome, but given its limited benefit to a good drawing, I still feel that my maintenance dollars are better spent elsewhere.

I apologize for the segue.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]
 
EWH,

I agree with the premise, that you wouldn't want people wasting time doing this and that it is largely redundant. I'll even throw in an extra technical reason (the only relevant one I know of) in that we threw out the last of the pen plotters probably over 10 years ago.

That's why I postulated that should it be used at all it ought to be automatic and associative. I'd even add that if you delete a dimension I'd like to see the gap in the other to go with it.

So having read all your posts and just to round out the topic, I wanted to say that I almost never use gaps anymore myself. It is not like I was pleading the case for extreme need. I have been using the old way which is admittedly cumbersome and somewhat counter intuitive for pretty much the whole time that it would have been in existence. I would explain that I use drafting relatively infrequently and employ this feature according to my own aesthetic judgment only where it really helps the clarity of dimensioning to clear a path through a spaghetti junction of dimensions that I haven't been able to otherwise avoid. I still think it is needed if only rarely and I hear users of other systems constantly harping that things are easier elsewhere. That being the case if you're going to have it as I think you must then if it could be better, so better would be good. But as to whether it would be a priority then the answer would have to be very much in the negative.

I only really mentioned it because I figured that it is so far out of date that it may eventually need to be brought up to the post NX-5 dialog standard, in which case some streamlining may make sense.

Cheers

Hudson
 
We are in agreement, Hudson. If it is used, it would be nice to have the efficiency that the rest of the software is moving toward, but as a priority, please let me do a three sided blend before any effort is spent on gaps.[peace]

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]
 
Fortunately those are two different development groups, so we can have both, but... EWH's comment earlier about the ASME Y14.4 section about this made me realize I've been doing this for nothing... but it would still be nice, if not "required". [2thumbsup]

-Derek
DL Engineering Services
specializing in CAD Design Consultation Services
 
Ewh,

If you mean a tri-tangent face blend, total agreement the recent post by Lurks bent us over backward trying to do this in NX.

The whole time I was painfully aware that there are systems out there that can do so. Lurks real problem wasn't the blend so much as his method (I suspect just learning NX) and the task he wanted to approach, but the tri-tangent face-blend would have come in handy.

In addition to this any face blends using the tangent to a curve method are not currently guaranteed to have internally tangent edges this also needs to improving upon. I expect all methods to provide total face-face tangency where implied and continuity where required, this is currently my biggest beef with the software. It is easy to get me fired up on what I'd really like when it comes to those subjects.

Derek,

As I said I seldom bother with gaps even though few organizations seem to actually read the standards they just seem to go with whatever they're used to in many cases, but nobody I know sweats on a gap for every cross over of dimension lines.

Cheers

Hudson
 
You can delete the gaps for extension lines at a time by switching extension lines off and making them on, instead of Edit->Component->Deelete Component.
 
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