# Edge over ngon not working as expected, face not selectable

I have this ngon which I am trying to turn into a quad, I added an edge split on the side (it wouldn't go all, over the top face) and then I added a vertex on the middle edge and connected to the new edge loop, however first of all:

1. I got a weird dotted line on my mirror
2. If I select the face it acts as if the line doesn't exist, looks like 2 faces are selected but it is actually one face with an ignored edge in the middle

Why is this happening?

• If you want to split a face by joining two vertices, use 'J' (Join) NOT 'F' (Fill). F will create a floating edge between the vertices but it will not split the face. Commented Jul 11, 2023 at 13:50
• @JohnEason Yes that's it! Can you post it as the answer please as it answers my question? Commented Jul 11, 2023 at 13:55
• Answer now posted. Commented Jul 11, 2023 at 14:25

If you want to split a face by joining two vertices, hit J (Join) not F (Fill). The images below demonstrate what happens when you use each method to join opposing vertices on a cube:

1> Using F (Fill):

This has created an edge between the vertices but it has not split the face:

You can demonstrate this by subdividing the line, grabbing the centre vertex created, and moving it up:

The edge is only connected to the face at the original vertices.

1. Using J (Join)

The result looks the same, but the face is actually split by the edge as you can see by selecting the triangular faces independently:

• Ha 😎 I haven't been use it in my 20 year experience, thanks for the answer. In this case I used a knife tool I guess ... Commented Jul 19, 2023 at 6:31
• Just something else to remember! :^) Commented Jul 19, 2023 at 8:07

I think that you have to delete this face and connect edges by yourself. Because I also often encounter such a problem, but it's usually enough for me to simply delete the face and connect everything on my own

If I were in this situation, I would delete the face that cause problem, and also delete the edge above the face. and then I would make one more edge loope not to make n gon.

you should remove the face and use a knife to get the middle line back