If I were to make a sphere and cut between a vertex near the sphere's "north" and a vertex near the sphere's "east," the cut becomes curved in a way reminiscent of the Coriolis effect. I just want the knife tool too cut through the edges between them in a straight line. In other words, I want it where knife tool cuts between two vertices always gives the same line cut (the shortest and most direct path possible) regardless of my viewer.


cutting sphere coriolis

I've had people tell me this is a result of having the view in perspective mode, which it clearly is not. Orthographic views also have this problem.


1 Answer 1


Knife tool works like that - it depends on the viewing angle how it cuts. If you want to join two vertices by the shortest path on surface between them, you can use 'Vertex Connect Path' function. It can be accessed from the vertex menu(Ctrl+v in edit mode) or simply by selecting two vertices and hitting j.

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  • $\begingroup$ The answer I was about to give .. but the OP had me trying to work out how 'J' determines the plane in which to make the cut. I think it cuts in the plane defined by [the chord between the points] and [the mean vertex normal of the points before the cut]? $\endgroup$
    – Robin Betts
    May 20, 2019 at 9:08
  • $\begingroup$ I am not sure to be honest. I assume it to be the shortest path. I don't know how the algorithm works, however it seems to be the case when testing. There is no detailed info about it in the documentation. $\endgroup$ May 20, 2019 at 9:25

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