Not only that, the object is no longer manifold, and I haven't been able to fix it. Look at the right side of the loop.


When a loop cut doesn't complete, it is usually because it hits a triangular face.

Before you did the loop cut, you have a misplaced quadrilateral. On the corner where the cut ends, there is an extra edge. If you move to the bottom corner of the object where the line is, there are two extra vertices.

The image below has the vertices highlighted.

Bad verticies

Delete these vertices and then try and complete the loop cut.

You have to ensure that no extra faces like in your mesh exist. If a loop cut fails, your mesh will almost always have an error like this or a triangular face.

Good luck with your project and I hope I helped,


  • 1
    $\begingroup$ It's not only tris that stop loops and they are usually easy to spot. ngons are a more common issue, especially when working in edge select mode. $\endgroup$ – metaphor_set Apr 3 '19 at 2:59
  • $\begingroup$ Yes, good point @metaphor_set. Hertforkc's model does not have a ngon, but it is a valid thing to look for and one i forgot to mention in my reply $\endgroup$ – Bigfoot Blondy Apr 3 '19 at 3:37
  • $\begingroup$ I noticed the extra vertices only after I did the loop cut. Thought they were the result of the fail and not the cause of it. Thank you. $\endgroup$ – Hertfordkc Apr 3 '19 at 9:35
  • $\begingroup$ Sorry, no cigar. I just went back to the file which I posted and pulled a copy of the uncut Cyl219W.002 from Object Window 7 and examined it. I didn't find the extra vertices. Did the Loop Cut and -BOOM- they're back. Were you able to repair the mesh, finish the loop cut and get a manifold result? $\endgroup$ – Hertfordkc Apr 3 '19 at 13:15
  • $\begingroup$ It was a simple enough repair. Delete the face and the extra vertices, the fill the faces. On your uncut model, are there any internal faces? Just an idea. I just found it odd that such formations appear due to a loop cut. Particularly when no misplaced vertex could be found. Check your normals just in case. Doubt it is the problem but who knows? Send the old file if you can $\endgroup$ – Bigfoot Blondy Apr 3 '19 at 13:19

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