Since moving to Rhino 6 we have had issues on some drawings (at least 50%) where the display of lines is in the wrong place.
Looking at the image it appears that I have just been lazy and not snapped the lines together, however all of those open ended lines are actually snapped to endpoints on the nearby lines. Unfortunately this isn’t a particularly extreme case, sometimes the displayed/real position of the lines are more exaggerated.
When control points are on you can see that the lines actually end in the right place, however the display is incorrect.
We never experienced this in Rhino 5, and until recently we have been able to get around it to some extent by enabling/disabling GPU Tessellation (I don’t remember which), however the setting that fixed this issue caused others.
Since updating to Version 6 SR10 (6.10.18311.20531, 11/7/2018) the GPU Tessellation trick no longer works and we are stuck with this incorrect display.
Our core work involves tracing from photography or laser scan data (using Veesus Arena4D) for building survey and historic recording, often to quite a high degree of accuracy, and so this display issue means we can’t be sure of the accuracy of our work.
Having a look through other posts, it seems to be related to the issues described in the following:
https://discourse.mcneel.com/t/control-points-not-nearly-exact/66689
and subsequently:
https://mcneel.myjetbrains.com/youtrack/issue/RH-44895
However turning GPU Tessellation now no longer works as suggested in that post.
I have, however found that changing the units from the metres that we normally use (and the only units that really make sense for the scale of most of our work) to millimetres fixes the issue (at least on the drawing I am working on).