non manifold vertices drove me mad

When I use Ctrl+Alt+Shit+M to find non manifold edge at edge select mode, nothing is selected.
But when I change to vertex select mode and Ctrl+Alt+Shift+M again, two vertices were found.
What’s wrong with these two vertices? Can anybody help me?

left_shoe.blend (1.03 MB)


Hard to tell from a picture. You have to attach a blend file.

Sorry to tell you this but the honest answer is that mesh is so messed up it would take you much longer to fix it than to scrap it and make a new one - of whatever it is. Start with a simple shape like a cube and angle the edges to approximate this geometry. Then add loopcuts to frame the area that you want to stick out, and then pull the central group of verts out to where you want. As it is you have way too much geometry and it’s all overlapping each other and triangles on top of it. Use quads, and use loops. I have done a demo mesh but since I don’t know what you’re going for it’s just to give you an idea.
The highlighted parts are things that affect the look of the mesh when editing so click them off and on to see the difference.

Don’t try to save this mesh. It will frustrate you!


left_shoe-fix.blend (1.34 MB)

To answer the question, your edges were manifold, your vertices were not. Your edges were connected to other edges, making them complete. The vertices, on the other hand, did not connect to something it thought it should have, creating a void.
If no possible camera angle can see the bad edge, you should be ok with animation/video games(like on a foot inside a shoe), but 3d printing needs manifold.
So, whats wrong with the vertices? They are allowing the camera to see inside a dimension it doesnt like. Like, if you were the architect of the world, you wouldnt want video-game-style clipping in the alps, so you would ensure that general area be rendered manifold

Hi DruBan,

Thank you for the advise. You really did a good job.
The model is just download from other guy’s. I plan to make it can be 3D printed.
To be a beginner, I just want to know the reason why it doesn’t work and learn to fix it first.
I just made the model become two parts. Each one of them seems manifold now. I don’t know whether it can be 3D printed.
Here comes more question:

  1. I tried to join the two parts with boolean operation, but those non manifold vertices come back again. Why?
  2. Maybe the cause is the two parts are hollow. Then I use solidify modifier, but the small part becomes very weird.

Anybody can help to solve that?

left_shoe3.blend (590 KB)

It still looks nothing like a shoe! No idea what you are going for. Probably you need to work on some basic modeling skills before trying to make something to be printed? One of the first things most people do is to get a reference image instead of trying to put what they see in their mind’s eye into a 3D model.

It’s not a shoe at all. It’s a part I separated from a shoe. I think the model is simple and you can figure out what the shape should be.
I really want to know how to fix the wrong elements in the model.
I will take many model repairing things before long, which is hard to learn skills from normal training.