I have an object with a high non manifold edge count. Is there a way to resolve them automatically or a way to make it easier to solve them manually?

Some of them are edges without a face and others are cubes connected to the object by one edge. The object have a high polygon count because it is the result of various modifiers applied.



When I delete those edges they leave others "non manifold edges" enter image description here After deletion, the solid is open and some new non manifold edges are formed enter image description here Using make faces creates some non manifold vertices enter image description here

  • $\begingroup$ What do you want to do to these (what do you mean by "resolve them")? Delete them? You can select them with Ctrl + Alt + Shift + M in edit mode $\endgroup$ – gandalf3 Aug 9 '13 at 16:52
  • $\begingroup$ I tried to delete them, but more non manifold edges are created. Then I used make face to close the opens, calculated non manifold edges again and repeated the process, but it takes a long time and it gave me the impression that a better and faster solution could exist. $\endgroup$ – Beothorn Aug 9 '13 at 17:09
  • $\begingroup$ Check out this post it provides good information on non-manifolds: 3dprintingninja.blogspot.com/2014/07/… $\endgroup$ – user8350 Dec 5 '14 at 20:08

Re-topology is the best option, since it will generate a clean mesh for 3d printing and will consume less time then removing unwanted cubes, edges etc.

In given situation, I'll first delete half of my model and add a mirror modifier to it. covert my mesh to Quads and remove extraneous edges and vertices manually.

Use BSurface Addon for Re-topology, as it is the fastest method.

  • $\begingroup$ Note that using the mirror modifier will only work with a symmetrical mesh. $\endgroup$ – gandalf3 Aug 9 '13 at 17:01
  • $\begingroup$ As gandalf3 said, the above method works only for symmetrical mesh. is there anyway to handle this for non-symmetrical meshes? I was wondering if it is possible to get the outer-surface shape of the geometry and build a clean mesh on it? $\endgroup$ – Benancio May 2 '16 at 15:18

If your concerned about non-manifold edges then you plan to 3D print this model. In that case I would add some "material" to the edges being joined. By that I mean some solid printed material that will hold the pieces together rather than a flimsy paper thin join that can break easily.

Start by separating the joined edges. Add a small bevel CtrlB so that the new edge is wide enough. You may want to display edge sizes while doing this, see Mesh display in the properties panel. The width you use here will depend on the material you plan to use, the width of the new edge added by the bevel should be at least the minimum material thickness you can use. Repeat for the other edge.

enter image description here

Select the vertices or edges around both new beveled faces and bridge edge loops (in the specials menu W)

enter image description here

This will remove the non-manifold edges and leave you with a solid join in your printed model.

enter image description here

You may want to bevel these new edges to get a more rounded join.

Another option is to move the cubes together so that both beveled edges meet up and then remove doubles. This will effectively make the corner of the cubes intersect a little and depends mostly on your needs. If your using the array modifier then you can intersect each cube by using and offset a little less than 1.0, I'm not certain if this overlapping non-connected geometry is acceptable for 3D printing so you may have to manually join the overlapping areas.

  • $\begingroup$ If I understood correctly you this manually. is there a way to do this by an script? in case there are many objects. $\endgroup$ – Benancio Mar 24 '16 at 15:39
  • $\begingroup$ I don't know of any script to automate this. $\endgroup$ – sambler Mar 24 '16 at 20:31

You can select all non-manifold edges/vertices by pressing Ctrl + Alt + Shift + M.

I don't know if this works for 3D printing, but you make it so Select non-manifold edges does not select those edges by making them separate:

enter image description here

So the cubes are separate, but those edges are in the same place. (one vert is move to the side in the image so you can see they are separate)

Another way you could try is the 3D print toolbox addon (introduced in 2.67), which has tools designed to help clean up meshes for 3D printing.

  • $\begingroup$ Thanks gandalf. I have edited my answer and added som screenshots. After deletion Ctrl + Alt + Shift + M still finds the connected edges to the deleted edges to be non manifold edges. Maybe deleting the edges fixes another scenario but it seems not to be my case. $\endgroup$ – Beothorn Aug 9 '13 at 17:34
  • $\begingroup$ @Lucass I have update my answer, but I don't know how well this solution will work in reality. The only other way I can think of is to connect those parts by more than a single edge. $\endgroup$ – gandalf3 Aug 9 '13 at 18:42

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