Inventor 2018 Bug: 3D Sketch Line Constraint Edit Deletes All Midpoints

[andrewiv]

I've run into what I believe to be a bug in the 3D sketch environment.  Create a 3D sketch and place 3 lines on the sketch.  Lock down two of lines so that they cannot move at all.  Now place a coincident constraint between the third line and the midpoint of each of the first two lines.  Now delete one of the midpoints and this is where the bug is.  It deletes all of the midpoints when you delete one.  Also the third line should show as fully constrained after the coincident constraints are applied (I know the endpoints aren't fully constrained yet, but if you do this same thing on a 2D sketch it shows as fully constrained).

Here is a screencast in case my description is confusing.

kelly.young has edited your subject line for clarity: 3D sketch bug

[johnsonshiue · Accepted solution]

Hi Andrew,

Many thanks for reporting the issue! It is a bug. I will work with the project team to understand the behavior better and see what we can do about it.

Thanks again!

[jhackney1972]

I can replicate your issue in a 3D sketch as you indicated.  I can also verify the same process in a 2D sketch does not give the same results, only one coincident constraint is deleted.  I will offer another method of deleted these constraints that will avoid your issue.  Take a look at my screencast and see my proposed method.  There is not sound to the recording.

[Xun.Zhang · Accepted solution]

@andrewiv,

It was confirmed as a defect at least from Inventor 2016.

Ticket INVGEN-12071 was open to track it down.

Thanks!

[andrewiv]

Thank you for the work around, I hadn't tried that one yet.  I did find another work around.  If you change the points that are created by the coincident constraint to center points, then only one gets deleted at a time.