(2017-08-12, 11:47)Philippe Hurbain Wrote: Not sure we are speaking of the same issue. I was speaking of vertices very close in 3d space, not 2d distance in screen projection. And I have seen thee condline problem described by Magnus for example between a well defined vertex at one end, and a cluster of very close vertices in 3d. The 2d problem is often not an issue, you just have to slightly adjust viewpoint. 2d is really an issue only when we try to work in -say- front view.
The problem is that "what is close" depends on the zoom level, too. At 1000% zoom 0.1 LDU is a long distance. At 0.1% zoom the vertices are indistinguishable.