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knife buggy cut
Closed, ResolvedPublic


System Information
Operating system and graphics card
windows and linux

Blender Version
Broken: Blender 2.71 "stable"
Worked: i don't remember a version of Blender in which the Bmesh knife was working without problems

Short description of error
Knife can duplicate vertices on cut edges, as reported here :

Exact steps for others to reproduce the error

  • Load the blend with Load UI so you get the same view and visual

  • press K and try to cut at these locations :

  • If you managed to did the cut roughly there, you'll notice the vertices there are doubled :

The oddity is that it does not happen everytime, but it happens.

Video of the bug from the original reporter on the Blenderartist board :

Revisions and Commits

Event Timeline

Sanc Tuary (sanctuary) raised the priority of this task from to 90.
Sanc Tuary (sanctuary) updated the task description. (Show Details)
Sanc Tuary (sanctuary) edited a custom field.

Thanks to Eppo pointing it, it looks like that problem can be avoided by scaling up the mesh, it looks like when edges are small (i mean something like 0.0x blender units, x being a number ) , the chances of the doubled vertices at a cut will increase a lot.

Sergey Sharybin (sergey) lowered the priority of this task from 90 to Normal.Jul 28 2014, 12:49 PM

When I cut it in mid-point, double vertices does not seem to appear.

I'm not having any success in making this bug appear with the supplied buggyknife.blend. I'll read through the forum thread and see if I can find another condition that may trigger it for me.

Oh, I see, there are doubled vertices (which I can tell by box selecting in wire mode), not just separated the way they were in the screen shot. So I confirm the problem and can work on it.