Disappearing Lines in NX8 Drafting

[JACater]

Hi, (Apologies this is my first post)

When moving my part part into the drafting stage some lines disappear.

It doesn't happen immediately but after manipulating some of the views using view dependent edits (on a section view and details of that view) the subsequent update of the sheet will cause some of the lines to disappear from the draft (no pattern in which lines go). From this point onward the lines are effectively 'deleted', they are not hidden by the view dependent edit or any show/hide feature.

The parent base view still has the missing lines, and any new section view has them as well. The issue appears to be triggered by one of details (not always the same one) and only affects the draft as far back as the section view. The update link between the parent and section view appears to be intact, however the parent is on a different sheet in the draft.

Any idea what is causing this or how to avoid it? I've been talking it over with the other NX users in the office and none of us can understand it.
Any help would be greatly appreciated as I've no doubt if i start the draft again (for the fifth time ) it'll just happen again.

 

[cowski]

When these types of weird things happen in drawing views, the first thing I do is go back to the part files where the geometry is defined and run "examine geometry" (found in the analysis menu). Turn on all the body and face checks then window select around your entire solid model (this will select the body, all faces, and all edges) and press "examine geometry". If the model doesn't pass one or more of these checks, it may be the cause of what you are seeing.

www.nxjournaling.com

 

[JACater]

Tried that and by the fact the part is all green i'm assuming it's fine. Thanks for the tip though, hadn't thought of checking that.

 

[cowski]

Have you tried changing the view tolerance? (found in view style -> general)
Sometimes changing to a different value (experiment with smaller & larger values) will fix display anomalies.

www.nxjournaling.com

 

[JACater]

Yeah, had a play around with all the view style settings in case i'd accidentally selected something when turning on the background clipping.

 

[JACater]

Sorted it, eventually!

It seems that the cause of the vanishing lines is quite simple. The assembly in question was created entirely of surface bodies rather then solid parts, When entering the drafting stage and creating section views these nominal thickness 'skins' were being cut.

As lines were removed using view dependent edit - after some initial back clipping - they would disappear. This is because while 9 times out of 10 the software selected the edge line of the surface occasionally it would select the entire face, which due to the view required would only consist of the two lines at the extremities of the face. This paired with the level of zoom required to pick out the lines in a crowded model meant that when the face was selected another edge line somewhere else in the view - and presumably off the screen - would be removed. However to the modeler it would only appear that the selected line was removed - until the next sheet refresh.

Because of the use of the View Dependent Edit tool the edge line associated with the deleted face is not recoverable (not sure why), hence the missing lines. The easiest way we have found to avoid this is to momentarily hover your cursor over the line in question before selecting it so the bubble pops up telling you what sort of geometry it is (i.e. line or face). Time consuming but necessary, alternatively use a solid model where possible it seems.

JC

 

[Toost]

It is recoverable. The face isn't deleted but erased in this view.
But, you must move the section view to the same sheet as the master view.
Then select the section view and RMB -view dep edit, click the "delete selected erasures" and bodies which have been completely erased will highlight in the master view... ( can be selected there also.)
It will not highlight in the section view... ( at least not in 7.5)

Regards,
Tomas