Missing hidden lines in 2D views

Jim Canale

I've submitted a support request on the following issue.    Bricsys staff disagrees with me on the necessity to fix this.  I'd like to hear others thoughts on the issue.   I've attached the drawing I sent to Bricsys support, to illustrate the problem.   

BricsCAD omitted a key hidden line from the 2D view shown at the bottom of  Layout1.    Support tells me it is because the hidden line is ALSO a tangent line.  However, tangent lines are seldom added to 2D drawings, and hidden lines (like the one that was omitted) are MUCH more important to properly represent an object.     And who wants to see a tangent edge on the backside of an object, anyway?   I had "tangent edges" turned off, because I didn't want to add  tangent edges to my 2D views.  I did however want key hidden lines to be displayed.

This issue occurs whether you use the "Generate Drawing Views" tool in V14, or the "QuickDraw" tool in V13.    I think they could fix this easily by prioritizing the display of hidden lines over tangent edges.

Thoughts anyone?  Am I being too picky?  

P. S.  I know I should have turned off the hidden lines in the isometric view.    

Knut Hohenberg

I think you have a point here.
I am not sure, however, if this is really a problem of priority - I would simply put it like this:
an edge that is not shown in the output should not occlude other edges.

Joe Dunfee

 The basic function of a CAD program is to create accurate drawings.  If it generates incorrect output (i.e. missing a line) then it is failing at doing an important part of its purpose.

Of course, in Mr. Canale's example, a work around would be to simply draw the mis-behaving line manually in paper space.  But, if the user does not notice the failure, then when they create their PDF or hard copy, it can create problems down the line.... sometimes those sorts of problems can be very expensive.  Checking a drawing PDF, to see if it actually has the stuff you drew, is not something a CAD program should require.

-Joe

Tim Neumann

I agree, there should be a hidden line there. No big deal but if it's supposed to automate then it should see it through. Pretty sure even flatshot would take of this but can't confirm it right now.

Joe Dunfee

 I will mention another possible work-around for Mr. Nunmann specific situation.  If the view is very slightly tilted, for example use the VPOINT command to rotate the view from the X-Y planes by 0.0001 degrees.  Then, the results will not be noticeable in the viewport, and perhaps so close to being a true orthographic view, that a dimension drawn in paper space may still read correctly.  Of course, the above depends upon the size of the part, and the precision settings of the dimensions.

This ideawon't work if the hidden and tangent lines are truly coincident.  It would only work if they have different elevations in regards to the current view.

Note that you typically have your angular precision set to a much lower number of decimal places, so if you do this you will not see the actual value for the viewpoint unless you set your angular units to show a similar number of decimal places, as what you want to set. If you don't do this, it will accept and record the values, though they aren't displayed.

-Joe

Jim Canale

Finally returning to this old thread, which I inadvertently dropped.   Sorry to all those who took time to reply to me..  I didn't realize until today, that I can subscribe to these threads and get notifications of answers.

Anyway, Bricsys support told me this issue (missing lines in generated views) was fixed in the next to last release of V14..  Then today I found a problem with another drawing.  (attached)  Shouldn't all internal features be represented by hidden lines, rather than tangent lines?   Aren't tangent lines only appropriate for outside surfaces?   

Joe the last paragraph of your last reply flew right over my head.

"...you will not see the actual value for the viewpoint unless you set your angular units to show a similar number of decimal places, as what you want to set. If you don't do this, it will accept and record the values, though they aren't displayed."

Can you explain this any better to this old simpleton? 

Joe Dunfee

@Jim Canale:

Joe the last paragraph of your last reply flew right over my head. 

"...you will not see the actual value for the viewpoint unless you set your angular units to show a similar number of decimal places, as what you want to set. If you don't do this, it will accept and record the values, though they aren't displayed."

Can you explain this any better to this old simpleton? 

Suppose you have your units set so that it displays angles to only 2 decimal places, and then later try to edit your view using the VPOINT command.  If you rotated your view by 0.0001 degree, and then laster used the VPOINT/ROTATE to see what you had done, it would show that you set it to 0.00 degrees.  You might incorrectly assume it was at 0 degrees, when it was in fact at 0.0001

-Joe

Jim Canale

Joe,

Thanks for your clarification.   I've never used VPOINT command, and didn't know it existed.  That's why I didn't understand.  I use the LOOK FROM toolbar to maneuver.  I didn't know I could shift the view by an angle.  I'll take a look at VPOINT, but I get very confused changing views.   I was so dyslexic in college that I flunked physics.   Someone can show me the picture of a cube, and I sometimes see the corner of a wall!  So switching from 2D drawings to 3D has been a big challenge for me.

Anyway, getting back on topic, I don't understand how changing the viewpoint for the 3D model will correct the problem with missing hidden lines on a 2D view.  Briscys says this was corrected a while back.  But the drawing I promised I'd upload (and forgot), says otherwise.  (I will post it now for sure.)   Bricsys support now tells me I have to turn on tangent edges to see the hidden features on this part.  I don't understand why the chamfer on a hole, would be considered a tangent edge, and not a hidden line. It seems to me, anything internal to the part would be considered first and foremost, a hidden line.   I've turned on tangent edges before, but only to highlight a feature on an external surface.
 

Plate - Errors Circled.dwg

Joe Dunfee

After looking at your drawing, I now realize that my approach will not help you. In some situations it helps because it causes lines that would otherwise be overlapping, to be very slightly off from each other. I tried my technique on your drawing, but it did not make a difference.

Personally, I would just accept the version with the tangent lines displayed.  Note that a very short line will not show its linetype, regardless of the linetype. So, even if it were a hidden linetype, it may not display any differently.

-Joe

Roy Klein Gebbinck

On my system (BC V14.2.11) there is a clear difference between the 'Tangent Edges OFF' layout and the 'Tangent Edges ON' layout. I would say the 'ON' layout is OK. What version are you using?

Jim Canale

Thanks again Joe.  

I haven't noticed any cases in which hidden lines are invisible on 2D views.  They may not be scaled correctly to show dashes, but they're still visible as solid lines.  I know that is not ideal, but it's better than nothing.   And I can always export the views to model space, explode them and tweak the line scaling.  

This situation however is quite different. An internal feature of the 3D model is being represented by a tangent edge, when I think it would be better represented by a hidden line.  There are cases in which a part has a lot of external radiused edges, where enabling TANGENT EDGES, makes  for a very "busy" 2D drawing.   It doesn't seem to me that I should have to accept this compromise just to show that the hole does indeed go all the way through the part.

It would be nice if we could selectively turn tangent edges on or off in specific views, particularly isometric views, but I think it unlikely Brics  I will get a lot of traction with BricsCAD support on this issue.   I believe they consider generation of 2D views a minor feature of the program.  

People have told me 2D drawings are dead.  And it is true that many, if not most machine shops work from 3D models.   But I'm not aware of any software that attaches tolerances, material requirements, finish requirements, etc. to a 3D model.  For that, I have to deliver a 2D drawing.  

Jim Canale

@Roy Klein Gebbinck:

On my system (BC V14.2.11) there is a clear difference between the 'Tangent Edges OFF' layout and the 'Tangent Edges ON' layout. I would say the 'ON' layout is OK. What version are you using?

Thanks Roy.      V14.2.17.  And yes, you and Joe and the Bricsys support staff are right.  The lines I need appear if I turn on tangent edges.   But I don't think it is a good idea to convert the internal features of parts to tangent lines.  I think they should be represented by hidden lines.    As I was saying to Joe, there are some cases when external radiused edges make a 2D view too "busy" if you have "Tangent Edges" turned on.    I don't think I should have to live with those extra lines just to make it clear that a hole goes all the way through a part.    But that is just my opinion.